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Atmospheric Environment (v.45, #25)
The impact of organic coatings on light scattering by sodium chloride particles by Yan Li; Michael J. Ezell; Barbara J. Finlayson-Pitts (pp. 4123-4132).
Light scattering by airborne particles plays a major role in visibility degradation and climate change. The composition and structure of particles in air can be complex, so that predictions of light scattering a priori have significant uncertainties. We report here studies of light scattering by NaCl, a model for airborne salt particles from the ocean and alkaline lakes, with and without an organic coating formed from the low volatility products of the reaction of α-pinene with ozone at room temperature at 1 atm in air. Light scattering at 450, 550 and 700 nm was measured using an integrating nephelometer on particles whose size distribution was independently determined using a scanning mobility particle sizer (SMPS). For comparison, polystyrene latex spheres (PSL) of a known size and dioctylphthalate (DOP) particles generated with a narrow size distribution were also studied. The measured values were compared to those calculated using Mie theory. Although excellent agreement between experiment and theory was found for the PSL and DOP particles, there were large discrepancies for a polydisperse NaCl sample. These were traced to errors in the size distribution measurements. Despite the use of85Kr neutralizers, the Boltzmann charge equilibrium distribution assumption used to derive particle size distributions from SMPS data was shown not to be valid, leading to an overestimate of the concentration of larger particles and their contribution to light scattering. Correcting for this, the combination of experiments and theory show that as salt takes up low volatility organics in the atmosphere and the geometric mean diameter increases, the effect on light scattering may be reasonably approximated from the change in size distribution under conditions where the organic coating is small relative to the core size. However, for a given particle diameter, light scattering decreases as the relative contribution of the organic component increases. Thus, light scattering by salt particles with a specific size distribution will be reduced when organics comprise a significant portion of the particles. This will lessen their impact on the visual range compared to pure salt particles, but also lead to less counterbalancing of the tropospheric warming due to greenhouse gases.► Organic coatings on NaCl particles decrease light scattering compared to pure NaCl. ► Thin organic coatings on NaCl increase light scattering via an increase in size. ►85Kr neutralizers may not always provide a Boltzmann equilibrium charge distribution.
Keywords: Light scattering; Sea salt; Secondary organic aerosol; Particle measurements
The impact of organic coatings on light scattering by sodium chloride particles by Yan Li; Michael J. Ezell; Barbara J. Finlayson-Pitts (pp. 4123-4132).
Light scattering by airborne particles plays a major role in visibility degradation and climate change. The composition and structure of particles in air can be complex, so that predictions of light scattering a priori have significant uncertainties. We report here studies of light scattering by NaCl, a model for airborne salt particles from the ocean and alkaline lakes, with and without an organic coating formed from the low volatility products of the reaction of α-pinene with ozone at room temperature at 1 atm in air. Light scattering at 450, 550 and 700 nm was measured using an integrating nephelometer on particles whose size distribution was independently determined using a scanning mobility particle sizer (SMPS). For comparison, polystyrene latex spheres (PSL) of a known size and dioctylphthalate (DOP) particles generated with a narrow size distribution were also studied. The measured values were compared to those calculated using Mie theory. Although excellent agreement between experiment and theory was found for the PSL and DOP particles, there were large discrepancies for a polydisperse NaCl sample. These were traced to errors in the size distribution measurements. Despite the use of85Kr neutralizers, the Boltzmann charge equilibrium distribution assumption used to derive particle size distributions from SMPS data was shown not to be valid, leading to an overestimate of the concentration of larger particles and their contribution to light scattering. Correcting for this, the combination of experiments and theory show that as salt takes up low volatility organics in the atmosphere and the geometric mean diameter increases, the effect on light scattering may be reasonably approximated from the change in size distribution under conditions where the organic coating is small relative to the core size. However, for a given particle diameter, light scattering decreases as the relative contribution of the organic component increases. Thus, light scattering by salt particles with a specific size distribution will be reduced when organics comprise a significant portion of the particles. This will lessen their impact on the visual range compared to pure salt particles, but also lead to less counterbalancing of the tropospheric warming due to greenhouse gases.► Organic coatings on NaCl particles decrease light scattering compared to pure NaCl. ► Thin organic coatings on NaCl increase light scattering via an increase in size. ►85Kr neutralizers may not always provide a Boltzmann equilibrium charge distribution.
Keywords: Light scattering; Sea salt; Secondary organic aerosol; Particle measurements
Soil mixing depth after atmospheric deposition. I. Model development and validation by Peter Drivas; Teresa Bowers; Robert Yamartino (pp. 4133-4140).
Knowledge of a soil mixing depth, or the migration depth of various pollutants in soil, is necessary to assess the soil chemical concentration resulting from atmospheric deposition of a specific air emission source. A mathematical model has been developed that describes the depth and time behavior of the soil concentration of an inert chemical after atmospheric deposition on surfaces. The soil mixing model is based on one-dimensional diffusion theory, and analytic solutions have been derived for the cases of: (1) instantaneous surface deposition; (2) continuous surface deposition; and (3) a finite period of continuous surface deposition, followed by a deposition-free time period. Comparisons of the model with measured soil depth profiles resulting from atmospheric deposition showed good agreement for lead, cesium, and dioxins. The best-fit effective diffusion coefficients in undisturbed soils varied from 0.5cm2yr−1 to 2cm2yr−1. The soil mixing depth was found to be a strong function of the atmospheric deposition time period. Calculated soil mixing depths in undisturbed soils were 2cm after one year, 5cm after five years, and 10cm after 20 years of continuous atmospheric deposition on the soil surface.► Mathematical model of soil depth mixing after atmospheric deposition. ► Soil mixing model is based on one-dimensional diffusion theory. ► Good agreement with measured data for lead, cesium, and dioxins. ► Effective diffusion coefficients varied from 0.5 to 2cm2yr−1. ► Soil mixing depth is strong function of deposition time period.
Keywords: Soil mixing depth; Atmospheric deposition; Mathematical modeling; Diffusion theory; Effective diffusion coefficient
Soil mixing depth after atmospheric deposition. I. Model development and validation by Peter Drivas; Teresa Bowers; Robert Yamartino (pp. 4133-4140).
Knowledge of a soil mixing depth, or the migration depth of various pollutants in soil, is necessary to assess the soil chemical concentration resulting from atmospheric deposition of a specific air emission source. A mathematical model has been developed that describes the depth and time behavior of the soil concentration of an inert chemical after atmospheric deposition on surfaces. The soil mixing model is based on one-dimensional diffusion theory, and analytic solutions have been derived for the cases of: (1) instantaneous surface deposition; (2) continuous surface deposition; and (3) a finite period of continuous surface deposition, followed by a deposition-free time period. Comparisons of the model with measured soil depth profiles resulting from atmospheric deposition showed good agreement for lead, cesium, and dioxins. The best-fit effective diffusion coefficients in undisturbed soils varied from 0.5cm2yr−1 to 2cm2yr−1. The soil mixing depth was found to be a strong function of the atmospheric deposition time period. Calculated soil mixing depths in undisturbed soils were 2cm after one year, 5cm after five years, and 10cm after 20 years of continuous atmospheric deposition on the soil surface.► Mathematical model of soil depth mixing after atmospheric deposition. ► Soil mixing model is based on one-dimensional diffusion theory. ► Good agreement with measured data for lead, cesium, and dioxins. ► Effective diffusion coefficients varied from 0.5 to 2cm2yr−1. ► Soil mixing depth is strong function of deposition time period.
Keywords: Soil mixing depth; Atmospheric deposition; Mathematical modeling; Diffusion theory; Effective diffusion coefficient
Vehicle non-exhaust emissions from the tyre–road interface – effect of stud properties, traction sanding and resuspension by Kaarle J. Kupiainen; Liisa Pirjola (pp. 4141-4146).
In Northern cities respirable street dust emission levels (PM10) are especially high during spring. The spring time dust has been observed to cause health effects as well as discomfort among citizens. Major sources of the dust are the abrasion products from the pavement and traction sand aggregates that are formed due to the motion of the tyre. We studied the formation of respirable abrasion particles in the tyre–road interface due to tyre studs and traction sanding by a mobile laboratory vehicle Sniffer. The measurements were preformed on a test track, where the influence of varying stud weight and stud number per tyre on PM10 emissions was studied. Studded tyres resulted in higher emission levels than studless tyres especially with speeds 50 km h−1 and higher; however, by using light weight studs, which approximately halves the weight of studs, or by reducing the number of studs per tyre to half, the emission levels decreased by approximately half. Additionally measurements were done with and without traction sand coverage on the pavement of a public road. After traction sanding the emission levels were not affected by tyre type but by formation and suspension of traction sand related dust from the road surface. The emissions after traction sanding decreased as a function of time as passing vehicles’ motion shifted the sand grains away from the areas with most tyre–road contact.► Stud properties (weight, number) affect the PM10 emissions caused by studded tyres. ► Traction sanding resulted in an episodic increase of PM10 emissions. ► Studded to studless tyre emission ratio is sensitive to the local suspension.
Keywords: Road dust; PM; 10; Mobile measurements; Studded tyres; Traction sanding; Resuspension
Vehicle non-exhaust emissions from the tyre–road interface – effect of stud properties, traction sanding and resuspension by Kaarle J. Kupiainen; Liisa Pirjola (pp. 4141-4146).
In Northern cities respirable street dust emission levels (PM10) are especially high during spring. The spring time dust has been observed to cause health effects as well as discomfort among citizens. Major sources of the dust are the abrasion products from the pavement and traction sand aggregates that are formed due to the motion of the tyre. We studied the formation of respirable abrasion particles in the tyre–road interface due to tyre studs and traction sanding by a mobile laboratory vehicle Sniffer. The measurements were preformed on a test track, where the influence of varying stud weight and stud number per tyre on PM10 emissions was studied. Studded tyres resulted in higher emission levels than studless tyres especially with speeds 50 km h−1 and higher; however, by using light weight studs, which approximately halves the weight of studs, or by reducing the number of studs per tyre to half, the emission levels decreased by approximately half. Additionally measurements were done with and without traction sand coverage on the pavement of a public road. After traction sanding the emission levels were not affected by tyre type but by formation and suspension of traction sand related dust from the road surface. The emissions after traction sanding decreased as a function of time as passing vehicles’ motion shifted the sand grains away from the areas with most tyre–road contact.► Stud properties (weight, number) affect the PM10 emissions caused by studded tyres. ► Traction sanding resulted in an episodic increase of PM10 emissions. ► Studded to studless tyre emission ratio is sensitive to the local suspension.
Keywords: Road dust; PM; 10; Mobile measurements; Studded tyres; Traction sanding; Resuspension
Personal exposure to PM2.5 among high-school students in Milan and background measurements: The EuroLifeNet study by A. Borgini; A. Tittarelli; C. Ricci; M. Bertoldi; E. De Saeger; P. Crosignani (pp. 4147-4151).
As part of the EuroLifeNet program we measured personal exposure to PM2.5 in 90 pupils attending three schools in Milan, over a three-week period spanning November and December 2006, using a portable light-scattering nephelometer. The primary aim was to investigate the relationship between personal exposure to PM2.5 and background measurements obtained from a fixed monitoring station. Pearson’s correlation coefficient between sampled daily mean exposures and reference values from background station varied from 0.64 to 0.75, with an overall value of 0.63, indicating good agreement. We also estimated that about 40% of the variability in the mean daily personal exposure at the three schools was due to variability in background exposure, the remaining 60% due to between-subject differences in exposures or to other sources of error.► Personal exposure to PM2.5 of pupils was measured using nephelometers. ► Comparison with fixed monitoring station was performed. ► A good overall correlation between the two measurements was found. ► 40% of variability in personal exposure was attributable to background variability.
Keywords: Personal exposure; Fine particles; Students; Schools; Indoor/outdoor
Personal exposure to PM2.5 among high-school students in Milan and background measurements: The EuroLifeNet study by A. Borgini; A. Tittarelli; C. Ricci; M. Bertoldi; E. De Saeger; P. Crosignani (pp. 4147-4151).
As part of the EuroLifeNet program we measured personal exposure to PM2.5 in 90 pupils attending three schools in Milan, over a three-week period spanning November and December 2006, using a portable light-scattering nephelometer. The primary aim was to investigate the relationship between personal exposure to PM2.5 and background measurements obtained from a fixed monitoring station. Pearson’s correlation coefficient between sampled daily mean exposures and reference values from background station varied from 0.64 to 0.75, with an overall value of 0.63, indicating good agreement. We also estimated that about 40% of the variability in the mean daily personal exposure at the three schools was due to variability in background exposure, the remaining 60% due to between-subject differences in exposures or to other sources of error.► Personal exposure to PM2.5 of pupils was measured using nephelometers. ► Comparison with fixed monitoring station was performed. ► A good overall correlation between the two measurements was found. ► 40% of variability in personal exposure was attributable to background variability.
Keywords: Personal exposure; Fine particles; Students; Schools; Indoor/outdoor
Multivariate analysis of respiratory problems and their connection with meteorological parameters and the main biological and chemical air pollutants by István Matyasovszky; László Makra; Beatrix Bálint; Zoltán Guba; Zoltán Sümeghy (pp. 4152-4159).
The aim of the study is to analyse the joint effect of biological (pollen) and chemical air pollutants, as well as meteorological variables, on the hospital admissions of respiratory problems for the Szeged region in Southern Hungary. The data set used covers a nine-year period (1999–2007) and is unique in the sense that it includes—besides the daily number of respiratory hospital admissions—not just the hourly mean concentrations of CO, PM10, NO, NO2, O3 and SO2 with meteorological variables (temperature, global solar flux, relative humidity, air pressure and wind speed), but two pollen variables ( Ambrosia and total pollen excluding Ambrosia) as well. The analysis was performed using three age categories for the pollen season of Ambrosia and the pollen-free season. Meteorological elements and air pollutants are clustered in order to define optimum environmental conditions of high patient numbers. ANOVA was then used to determine whether cluster-related mean patient numbers differ significantly. Furthermore, two novel procedures are applied here: factor analysis including a special transformation and a time-varying multivariate linear regression that makes it possible to determine the rank of importance of the influencing variables in respiratory hospital admissions, and also compute the relative importance of the parameters affecting respiratory disorders. Both techniques revealed that Ambrosia pollen is an important variable that influences hospital admissions (an increase of 10 pollen grains m−3 can imply an increase of around 24% in patient numbers). The role of chemical and meteorological parameters is also significant, but their weights vary according to the seasons and the methods. Clearer results are obtained for the pollination season of Ambrosia. Here, a 10 μg m−3 increase in O3 implies a patient number response from −17% to +11%. Wind speed is a surprisingly important variable, where a 1 m s−1 rise may result in a hospital admission reduction of up to 42–45%.► Effects of the influencing variables on the respiratory problems differ per seasons. ► The order of importance of influencing variables is highly variable among age groups. ► Ambrosia pollen and O3 are key variables influencing hospital admissions. ► Rise of wind speed may cause a surprisingly notable reduction in hospital admission.
Keywords: Air pollution; Respiratory hospital admissions; Cluster analysis; Factor analysis including a special transformation; Time-varying multivariate linear regression
Multivariate analysis of respiratory problems and their connection with meteorological parameters and the main biological and chemical air pollutants by István Matyasovszky; László Makra; Beatrix Bálint; Zoltán Guba; Zoltán Sümeghy (pp. 4152-4159).
The aim of the study is to analyse the joint effect of biological (pollen) and chemical air pollutants, as well as meteorological variables, on the hospital admissions of respiratory problems for the Szeged region in Southern Hungary. The data set used covers a nine-year period (1999–2007) and is unique in the sense that it includes—besides the daily number of respiratory hospital admissions—not just the hourly mean concentrations of CO, PM10, NO, NO2, O3 and SO2 with meteorological variables (temperature, global solar flux, relative humidity, air pressure and wind speed), but two pollen variables ( Ambrosia and total pollen excluding Ambrosia) as well. The analysis was performed using three age categories for the pollen season of Ambrosia and the pollen-free season. Meteorological elements and air pollutants are clustered in order to define optimum environmental conditions of high patient numbers. ANOVA was then used to determine whether cluster-related mean patient numbers differ significantly. Furthermore, two novel procedures are applied here: factor analysis including a special transformation and a time-varying multivariate linear regression that makes it possible to determine the rank of importance of the influencing variables in respiratory hospital admissions, and also compute the relative importance of the parameters affecting respiratory disorders. Both techniques revealed that Ambrosia pollen is an important variable that influences hospital admissions (an increase of 10 pollen grains m−3 can imply an increase of around 24% in patient numbers). The role of chemical and meteorological parameters is also significant, but their weights vary according to the seasons and the methods. Clearer results are obtained for the pollination season of Ambrosia. Here, a 10 μg m−3 increase in O3 implies a patient number response from −17% to +11%. Wind speed is a surprisingly important variable, where a 1 m s−1 rise may result in a hospital admission reduction of up to 42–45%.► Effects of the influencing variables on the respiratory problems differ per seasons. ► The order of importance of influencing variables is highly variable among age groups. ► Ambrosia pollen and O3 are key variables influencing hospital admissions. ► Rise of wind speed may cause a surprisingly notable reduction in hospital admission.
Keywords: Air pollution; Respiratory hospital admissions; Cluster analysis; Factor analysis including a special transformation; Time-varying multivariate linear regression
Multicriteria methodological approach to manage urban air pollution by Ch. Vlachokostas; Ch. Achillas; N. Moussiopoulos; G. Banias (pp. 4160-4169).
Managing urban air pollution necessitates a feasible and efficient abatement strategy which is characterised as a defined set of specific control measures. In practice, hard budget constraints are present in any decision-making process and therefore available alternatives need to be hierarchised in a fast but still reliable manner. Moreover, realistic strategies require adequate information on the available control measures, taking also into account the area’s special characteristics. The selection of the most applicable bundle of measures rests in achieving stakeholders’ consensus, while taking into consideration mutually conflicting views and criteria. A preliminary qualitative comparison of alternative control measures would be most handy for decision-makers, forming the grounds for an in-depth analysis of the most promising ones. This paper presents an easy-to-follow multicriteria methodological approach in order to include and synthesise multi-disciplinary knowledge from various stakeholders so as to result into a priority list of abatement options, achieve consensus and secure the adoption of the resulting optimal solution. The approach relies on the active involvement of public authorities and local stakeholders in order to incorporate their environmental, economic and social preferences. The methodological scheme is implemented for the case of Thessaloniki, Greece, an area considered among the most polluted cities within Europe, especially with respect to airborne particles. Intense police control, natural gas penetration in buildings and metro construction equally result into the most “promising” alternatives in order to control air pollution in the GTA. The three optimal alternatives belong to different thematic areas, namely road transport, thermal heating and infrastructure. Thus, it is obvious that efforts should spread throughout all thematic areas. Natural gas penetration in industrial units, intense monitoring of environmental standards and regular maintenance of heavy oil burners are ranked as 4th, 5th and 6th optimal alternatives, respectively.► Prioritisation of measures to confront air quality deterioration in urban areas. ► Ranking of available improvement strategies due to budget constraints. ► Easy-to-follow multicriteria approach that synthesises multi-disciplinary knowledge. ► Consensus among local stakeholders.
Keywords: Air pollution; Multicriteria analysis; Decision-making; Control options; Experts
Multicriteria methodological approach to manage urban air pollution by Ch. Vlachokostas; Ch. Achillas; N. Moussiopoulos; G. Banias (pp. 4160-4169).
Managing urban air pollution necessitates a feasible and efficient abatement strategy which is characterised as a defined set of specific control measures. In practice, hard budget constraints are present in any decision-making process and therefore available alternatives need to be hierarchised in a fast but still reliable manner. Moreover, realistic strategies require adequate information on the available control measures, taking also into account the area’s special characteristics. The selection of the most applicable bundle of measures rests in achieving stakeholders’ consensus, while taking into consideration mutually conflicting views and criteria. A preliminary qualitative comparison of alternative control measures would be most handy for decision-makers, forming the grounds for an in-depth analysis of the most promising ones. This paper presents an easy-to-follow multicriteria methodological approach in order to include and synthesise multi-disciplinary knowledge from various stakeholders so as to result into a priority list of abatement options, achieve consensus and secure the adoption of the resulting optimal solution. The approach relies on the active involvement of public authorities and local stakeholders in order to incorporate their environmental, economic and social preferences. The methodological scheme is implemented for the case of Thessaloniki, Greece, an area considered among the most polluted cities within Europe, especially with respect to airborne particles. Intense police control, natural gas penetration in buildings and metro construction equally result into the most “promising” alternatives in order to control air pollution in the GTA. The three optimal alternatives belong to different thematic areas, namely road transport, thermal heating and infrastructure. Thus, it is obvious that efforts should spread throughout all thematic areas. Natural gas penetration in industrial units, intense monitoring of environmental standards and regular maintenance of heavy oil burners are ranked as 4th, 5th and 6th optimal alternatives, respectively.► Prioritisation of measures to confront air quality deterioration in urban areas. ► Ranking of available improvement strategies due to budget constraints. ► Easy-to-follow multicriteria approach that synthesises multi-disciplinary knowledge. ► Consensus among local stakeholders.
Keywords: Air pollution; Multicriteria analysis; Decision-making; Control options; Experts
Sectoral CO2, CH4, N2O and SO2 emissions from fossil fuel consumption in Nagpur City of Central India by Deepanjan Majumdar; D.G. Gajghate (pp. 4170-4179).
Emission inventory of CO2, CH4, N2O and SO2 has been prepared for Nagpur city in Central India for the year 2004. Data on fossil fuel (coal, light diesel oil, high speed diesel, petrol/gasoline, low sulphur heavy stock, furnace oil and kerosene) consumption in thermal power, industrial, transport and domestic sectors were collected. Thermal power sector had the maximum coal consumption followed by the industrial and domestic sectors, whereas kerosene, liquefied petroleum gas (LPG), diesel and gasoline were used only in any single sector. Total annual CO2, CH4, N2O and SO2 emissions from these fuels in Nagpur city for the year 2004 was found to be 14792418 MT (14.8 Tg), 4649 (4.6 Tg), 1529 (1.5 Tg) and 69093 (6.9 Tg), respectively, in which thermal power and domestic sector had the maximum share. Coal was found to be the major contributor to Green House Gas (GHG) and SO2 emissions in all the sectors barring transport and domestic sectors. Carbon dioxide was the predominant GHG emitted by the selected sectors in terms of absolute emissions and also global warming contribution (GWC), though the share in the latter was lesser in magnitude due to higher global warming potential (GWP) of CH4 and N2O than CO2. Thermal power sector had a share of 51% in total CO2 emissions from all the sectors, followed by domestic, industrial and transport sectors having 27, 12 and 10% contributions, respectively. Share of thermal power sector in total SO2 emissions was 61%, followed by 24% from industrial, 10% from domestic and 5% from transport sector.► Sectoral CO2, CH4, N2O and SO2 emissions of Nagpur city were estimated for 2004. ► Annual CO2, CH4, N2O and SO2 emissions were 14792418, 4649, 1529, 69093 MT. ► Coal was the major contributor to the emissions in power and industrial sectors. ► Thermal power, domestic, industrial sectors had 51, 27, 12% share in CO2 emission. ► Thermal power, industrial, domestic sectors had 61, 24, 10 share in SO2 emissions.
Keywords: Climate change; Coal; Diesel; Emission inventory; Global warming
Sectoral CO2, CH4, N2O and SO2 emissions from fossil fuel consumption in Nagpur City of Central India by Deepanjan Majumdar; D.G. Gajghate (pp. 4170-4179).
Emission inventory of CO2, CH4, N2O and SO2 has been prepared for Nagpur city in Central India for the year 2004. Data on fossil fuel (coal, light diesel oil, high speed diesel, petrol/gasoline, low sulphur heavy stock, furnace oil and kerosene) consumption in thermal power, industrial, transport and domestic sectors were collected. Thermal power sector had the maximum coal consumption followed by the industrial and domestic sectors, whereas kerosene, liquefied petroleum gas (LPG), diesel and gasoline were used only in any single sector. Total annual CO2, CH4, N2O and SO2 emissions from these fuels in Nagpur city for the year 2004 was found to be 14792418 MT (14.8 Tg), 4649 (4.6 Tg), 1529 (1.5 Tg) and 69093 (6.9 Tg), respectively, in which thermal power and domestic sector had the maximum share. Coal was found to be the major contributor to Green House Gas (GHG) and SO2 emissions in all the sectors barring transport and domestic sectors. Carbon dioxide was the predominant GHG emitted by the selected sectors in terms of absolute emissions and also global warming contribution (GWC), though the share in the latter was lesser in magnitude due to higher global warming potential (GWP) of CH4 and N2O than CO2. Thermal power sector had a share of 51% in total CO2 emissions from all the sectors, followed by domestic, industrial and transport sectors having 27, 12 and 10% contributions, respectively. Share of thermal power sector in total SO2 emissions was 61%, followed by 24% from industrial, 10% from domestic and 5% from transport sector.► Sectoral CO2, CH4, N2O and SO2 emissions of Nagpur city were estimated for 2004. ► Annual CO2, CH4, N2O and SO2 emissions were 14792418, 4649, 1529, 69093 MT. ► Coal was the major contributor to the emissions in power and industrial sectors. ► Thermal power, domestic, industrial sectors had 51, 27, 12% share in CO2 emission. ► Thermal power, industrial, domestic sectors had 61, 24, 10 share in SO2 emissions.
Keywords: Climate change; Coal; Diesel; Emission inventory; Global warming
Source apportionment and spatial variability of PM2.5 using measurements at five sites in the Netherlands by D. Mooibroek; M. Schaap; E.P. Weijers; R. Hoogerbrugge (pp. 4180-4191).
The Netherlands is considered one of the hotspot areas in Europe with high concentrations of particulate matter (PM) and may not be able to meet all standards for PM2.5 in time with current legislation (). To improve our understanding of the composition, distribution and origin of PM2.5 in the ambient air an intensive one-year measurement campaign (from August 2007 to September 2008) was performed at five locations in the Netherlands. The five sites consist of three rural background sites, one urban background site and one curbside site. We have applied source apportionment using Positive Matrix Factorization (EPA-PMF) on the pooled data from the five sites to identify and quantify the most relevant source contributions and their spatial variability to PM2.5 in the Netherlands. The results of this study are compared to a full mass closure analysis of the data. Using EPA-PMF we could identify seven unique sources for the PM2.5 fraction: nitrate-rich secondary aerosol, sulphate-rich secondary aerosol, traffic and resuspended road dust, industrial (metal) activities/incineration, sea spray, crustal material and residual oil combustion. Wind directional analysis was used to determine the possible locations of the identified sources. On the five locations secondary inorganic aerosol (SIA) is responsible for the largest contribution. The contribution of SIA to the total PM2.5 mass is largely constant at all used sites. This indicates these sources are common sources which behave like area sources and affects each site. The largest contribution of the traffic and resuspended road dust profile was found at the curbside site. Using combined data from five measurement sites provides focus on the common sources (e.g. SIA) affecting all locations.► Seven unique sources for the PM2.5 fraction could be identified. ► SIA has the largest and fairly constant contribution to the total PM2.5 mass on all sites. ► Highest contribution of the traffic related sources on the kerbside location. ► Wind directional analysis corresponds with the expected locations of sources. ► Combining the data focuses on common sources, instead of unique (local) sources.
Keywords: Source apportionment; PM; 2.5; Positive matrix factorization; PMF; Multilinear engine; ME-2; Spatial variability
Source apportionment and spatial variability of PM2.5 using measurements at five sites in the Netherlands by D. Mooibroek; M. Schaap; E.P. Weijers; R. Hoogerbrugge (pp. 4180-4191).
The Netherlands is considered one of the hotspot areas in Europe with high concentrations of particulate matter (PM) and may not be able to meet all standards for PM2.5 in time with current legislation (). To improve our understanding of the composition, distribution and origin of PM2.5 in the ambient air an intensive one-year measurement campaign (from August 2007 to September 2008) was performed at five locations in the Netherlands. The five sites consist of three rural background sites, one urban background site and one curbside site. We have applied source apportionment using Positive Matrix Factorization (EPA-PMF) on the pooled data from the five sites to identify and quantify the most relevant source contributions and their spatial variability to PM2.5 in the Netherlands. The results of this study are compared to a full mass closure analysis of the data. Using EPA-PMF we could identify seven unique sources for the PM2.5 fraction: nitrate-rich secondary aerosol, sulphate-rich secondary aerosol, traffic and resuspended road dust, industrial (metal) activities/incineration, sea spray, crustal material and residual oil combustion. Wind directional analysis was used to determine the possible locations of the identified sources. On the five locations secondary inorganic aerosol (SIA) is responsible for the largest contribution. The contribution of SIA to the total PM2.5 mass is largely constant at all used sites. This indicates these sources are common sources which behave like area sources and affects each site. The largest contribution of the traffic and resuspended road dust profile was found at the curbside site. Using combined data from five measurement sites provides focus on the common sources (e.g. SIA) affecting all locations.► Seven unique sources for the PM2.5 fraction could be identified. ► SIA has the largest and fairly constant contribution to the total PM2.5 mass on all sites. ► Highest contribution of the traffic related sources on the kerbside location. ► Wind directional analysis corresponds with the expected locations of sources. ► Combining the data focuses on common sources, instead of unique (local) sources.
Keywords: Source apportionment; PM; 2.5; Positive matrix factorization; PMF; Multilinear engine; ME-2; Spatial variability
Potential threat of heavy metals in re-suspended dusts on building surfaces in oilfield city by Shaofei Kong; Bing Lu; Zhipeng Bai; Xueyan Zhao; Li Chen; Bin Han; Zhiyong Li; Yaqin Ji; Yonghai Xu; Yong Liu; Hua Jiang (pp. 4192-4204).
30 re-suspended dust samples were collected from building surfaces of an oilfield city, then re-suspended through PM2.5, PM10 and PM100 inlets and analyzed for 10 metals including V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb by inductively coupled plasma-mass spectroscopy. Metals concentrations in different fractions and locations were studied. Metals sources were identified by cluster and primary component analysis. The potential risk to human health was assessed by human exposure model. Results showed that Zn, Mn, Pb and Cu were higher in all the three fractions. V, Cr, Mn and Co ranged close to the background values of Chinese soil indicating that they were mainly from crustal materials. Concentrations of Zn, Mn, Pb, V, Cr, Ni, Co and Cd were higher in old district than that in new district for the three fractions. The PM2.5/PM10, PM10/PM100 and PM2.5/PM100 ratios were higher for Zn, Cd, Cu, Pb, Ni, As and Cr (all higher than 1.0), and lower for Co, Mn and V (all less than or close to 1.0) which meant that anthropologic sources associated metals were more easily accumulated in finer particles than metals from crustal materials. Spatial variations indicated that the ten metals peaked at surroundings near railway station, gas stations, industrial boilers and machine manufacturing plant implying the influence of local vehicle emission, fossil fuel combustion and industrial activities as well as crustal materials which was verified by cluster analysis and primary component analysis results. Ingestion of dust particles appeared to be the main route of exposure to re-suspended dust. Hazard Indexes of As were both highest for children and adult which could be a potential threat to human health for non-cancer effect and it also exhibited the highest values for cancer effect as 1.01E-06, 7.04E-07 and 7.21E-07 for PM2.5, PM10 and PM100, respectively.► Ten metals in PM2.5, PM10 and PM100 of re-suspended dust were studied. ► An oilfield city was selected as the target. ► Human related metals were more easily accumulated in finer particles. ► Human exposure to metals in re-suspended dust was assessed. ► As exhibited highest non-cancer and cancer risk for human health.
Keywords: Heavy metals; Re-suspended dust; Dongying; Sources; Health risk; Oilfield city
Potential threat of heavy metals in re-suspended dusts on building surfaces in oilfield city by Shaofei Kong; Bing Lu; Zhipeng Bai; Xueyan Zhao; Li Chen; Bin Han; Zhiyong Li; Yaqin Ji; Yonghai Xu; Yong Liu; Hua Jiang (pp. 4192-4204).
30 re-suspended dust samples were collected from building surfaces of an oilfield city, then re-suspended through PM2.5, PM10 and PM100 inlets and analyzed for 10 metals including V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb by inductively coupled plasma-mass spectroscopy. Metals concentrations in different fractions and locations were studied. Metals sources were identified by cluster and primary component analysis. The potential risk to human health was assessed by human exposure model. Results showed that Zn, Mn, Pb and Cu were higher in all the three fractions. V, Cr, Mn and Co ranged close to the background values of Chinese soil indicating that they were mainly from crustal materials. Concentrations of Zn, Mn, Pb, V, Cr, Ni, Co and Cd were higher in old district than that in new district for the three fractions. The PM2.5/PM10, PM10/PM100 and PM2.5/PM100 ratios were higher for Zn, Cd, Cu, Pb, Ni, As and Cr (all higher than 1.0), and lower for Co, Mn and V (all less than or close to 1.0) which meant that anthropologic sources associated metals were more easily accumulated in finer particles than metals from crustal materials. Spatial variations indicated that the ten metals peaked at surroundings near railway station, gas stations, industrial boilers and machine manufacturing plant implying the influence of local vehicle emission, fossil fuel combustion and industrial activities as well as crustal materials which was verified by cluster analysis and primary component analysis results. Ingestion of dust particles appeared to be the main route of exposure to re-suspended dust. Hazard Indexes of As were both highest for children and adult which could be a potential threat to human health for non-cancer effect and it also exhibited the highest values for cancer effect as 1.01E-06, 7.04E-07 and 7.21E-07 for PM2.5, PM10 and PM100, respectively.► Ten metals in PM2.5, PM10 and PM100 of re-suspended dust were studied. ► An oilfield city was selected as the target. ► Human related metals were more easily accumulated in finer particles. ► Human exposure to metals in re-suspended dust was assessed. ► As exhibited highest non-cancer and cancer risk for human health.
Keywords: Heavy metals; Re-suspended dust; Dongying; Sources; Health risk; Oilfield city
Speciated atmospheric mercury and its potential source in Guiyang, China by Xuewu Fu; Xinbin Feng; Guangle Qiu; Lihai Shang; Hui Zhang (pp. 4205-4212).
Speciated atmospheric mercury (Hg) including gaseous elemental mercury (GEM), particulate Hg (PHg), and reactive gaseous Hg (RGM) were continuously measured at an urban site in Guiyang city, southwest China from August to December 2009. The averaged concentrations for GEM, PHg, and RGM were 9.72 ± 10.2 ng m−3, 368 ± 676 pg m−3, and 35.7 ± 43.9 pg m−3, respectively, which were all highly elevated compared to observations at urban sites in Europe and North America. GEM and PHg were characterized by similar monthly and diurnal patterns, with elevated levels in cold months and nighttime, respectively. In contrast, RGM did not exhibit clear monthly and diurnal variations. The variations of GEM, PHg, and RGM indicate the sampling site was significantly impacted by sources in the city municipal area. Sources identification implied that both residential coal burning and large point sources were responsible to the elevated GEM and PHg concentrations; whereas point sources were the major contributors to elevated RGM concentrations. Point sources played a different role in regulating GEM, PHg, and RGM concentrations. Aside from residential emissions, PHg levels was mostly affected by small-scale coal combustion boilers situated to the east of the sampling site, which were scarcely equipped or lacking particulate control devices; whereas point sources situated to the east, southeast, and southwest of the sampling played an important role on the distribution of atmospheric GEM and RGM.► Speciated atmospheric Hg levels in Guiyang, China were highly elevated. ► GEM and PHg were affected by domestic and industrial point sources. ► RGM was dominantly affected by industrial point sources.
Keywords: Speciated atmospheric mercury; Urban area; Sources; China
Speciated atmospheric mercury and its potential source in Guiyang, China by Xuewu Fu; Xinbin Feng; Guangle Qiu; Lihai Shang; Hui Zhang (pp. 4205-4212).
Speciated atmospheric mercury (Hg) including gaseous elemental mercury (GEM), particulate Hg (PHg), and reactive gaseous Hg (RGM) were continuously measured at an urban site in Guiyang city, southwest China from August to December 2009. The averaged concentrations for GEM, PHg, and RGM were 9.72 ± 10.2 ng m−3, 368 ± 676 pg m−3, and 35.7 ± 43.9 pg m−3, respectively, which were all highly elevated compared to observations at urban sites in Europe and North America. GEM and PHg were characterized by similar monthly and diurnal patterns, with elevated levels in cold months and nighttime, respectively. In contrast, RGM did not exhibit clear monthly and diurnal variations. The variations of GEM, PHg, and RGM indicate the sampling site was significantly impacted by sources in the city municipal area. Sources identification implied that both residential coal burning and large point sources were responsible to the elevated GEM and PHg concentrations; whereas point sources were the major contributors to elevated RGM concentrations. Point sources played a different role in regulating GEM, PHg, and RGM concentrations. Aside from residential emissions, PHg levels was mostly affected by small-scale coal combustion boilers situated to the east of the sampling site, which were scarcely equipped or lacking particulate control devices; whereas point sources situated to the east, southeast, and southwest of the sampling played an important role on the distribution of atmospheric GEM and RGM.► Speciated atmospheric Hg levels in Guiyang, China were highly elevated. ► GEM and PHg were affected by domestic and industrial point sources. ► RGM was dominantly affected by industrial point sources.
Keywords: Speciated atmospheric mercury; Urban area; Sources; China
Comparison between knife-edge and frisbee-shaped surrogate surfaces for making dry deposition measurements: Wind tunnel experiments and computational fluid dynamics (CFD) modeling by Jiaoyan Huang; Ying Liu; Thomas M. Holsen (pp. 4213-4219).
Dry deposition is a major pathway for atmospheric contaminant movement from the atmosphere to the earth surface. Despite its importance, there is no generally accepted direct method to measure dry deposition. Recently, the interest in using surrogate surfaces to measure dry deposition is growing, primarily because of their ease of use. However, a problem with these surfaces is extrapolating the results obtained to natural surfaces. There are two popular surrogate plates used to measure dry deposition. One had a sharp leading edge (knife-edge) (KSS), and the other has a smooth-edge (frisbee-shaped) (FSS). In this study, the performances of these two surrogate surfaces to directly measure gas dry deposition were explored using wind tunnel experiments and two-dimensional (2D) computational fluid dynamic (CFD) models. Although the fluid fields above these two plates were different, both created laminar boundary layers (distance above the surface where the velocity gradient is constant) with a constant thickness after approximately five cm. In the wind tunnel, gaseous elemental mercury (GEM) deposition to gold-coated filters was used to measure deposition velocities ( Vd) in part because for this combination deposition is air-side controlled. The GEM Vd to both surfaces increased with increasing wind speeds. Based on both measurements and CFD simulations, the Vds to the FSS were approximately 30% higher and more variable than to the KSS when the wind flow was parallel to the surfaces. However, when the angle between the surfaces and the wind was varied the Vds to the FSS were less dependent on the incident angle than to the KSS.► Knife-edge (KSS) and frisbee-shaped (FSS) surrogate surfaces were tested. ► The boundary layer height was constant starting 5 cm from the leading edges. ► GEM dry deposition rates were more variable and higher to the FSS than to the KSS. ► GEM dry deposition rates increased when flow was not parallel to the surfaces. ► The reaction constant between Hg(aq) and BrCl(aq) was 6.7 ± 2.3 × 105 M−1 s−1.
Keywords: Surrogated surface; Knife-edge; Frisbee-shaped; Gas dry deposition; Wind tunnel
Comparison between knife-edge and frisbee-shaped surrogate surfaces for making dry deposition measurements: Wind tunnel experiments and computational fluid dynamics (CFD) modeling by Jiaoyan Huang; Ying Liu; Thomas M. Holsen (pp. 4213-4219).
Dry deposition is a major pathway for atmospheric contaminant movement from the atmosphere to the earth surface. Despite its importance, there is no generally accepted direct method to measure dry deposition. Recently, the interest in using surrogate surfaces to measure dry deposition is growing, primarily because of their ease of use. However, a problem with these surfaces is extrapolating the results obtained to natural surfaces. There are two popular surrogate plates used to measure dry deposition. One had a sharp leading edge (knife-edge) (KSS), and the other has a smooth-edge (frisbee-shaped) (FSS). In this study, the performances of these two surrogate surfaces to directly measure gas dry deposition were explored using wind tunnel experiments and two-dimensional (2D) computational fluid dynamic (CFD) models. Although the fluid fields above these two plates were different, both created laminar boundary layers (distance above the surface where the velocity gradient is constant) with a constant thickness after approximately five cm. In the wind tunnel, gaseous elemental mercury (GEM) deposition to gold-coated filters was used to measure deposition velocities ( Vd) in part because for this combination deposition is air-side controlled. The GEM Vd to both surfaces increased with increasing wind speeds. Based on both measurements and CFD simulations, the Vds to the FSS were approximately 30% higher and more variable than to the KSS when the wind flow was parallel to the surfaces. However, when the angle between the surfaces and the wind was varied the Vds to the FSS were less dependent on the incident angle than to the KSS.► Knife-edge (KSS) and frisbee-shaped (FSS) surrogate surfaces were tested. ► The boundary layer height was constant starting 5 cm from the leading edges. ► GEM dry deposition rates were more variable and higher to the FSS than to the KSS. ► GEM dry deposition rates increased when flow was not parallel to the surfaces. ► The reaction constant between Hg(aq) and BrCl(aq) was 6.7 ± 2.3 × 105 M−1 s−1.
Keywords: Surrogated surface; Knife-edge; Frisbee-shaped; Gas dry deposition; Wind tunnel
Sub-grid variability and its impact on European wide air quality exposure assessment by Bruce Denby; Massimo Cassiani; Peter de Smet; Frank de Leeuw; Jan Horálek (pp. 4220-4229).
Estimates of population exposure to air pollution on the European scale are required for policy development and health impact assessment. Long term exposure estimates of this type can be made using spatially distributed air quality and population density data. Gridded chemical transport models (CTMs) are often used for this purpose, however the grid resolution of CTMs that cover entire continents is usually limited to 25–100 km and there may be a significant level of unresolved variability within the grids that will impact on the exposure estimates. In this paper sub-grid variability and its impact on long term exposure estimates is assessed by investigating the covariance of concentration and population, which is shown to be the defining term in estimating the average sub-grid population exposure. A parameterisation of the sub-grid covariance is described, based on the sub-grid covariance of other proxy data, and this is applied using EMEP model results for all of Europe. The study shows that the error made in the exposure calculations for all of Europe is significant for the typical CTM resolution of 50 km. The error is largest for NO2, where the average European urban background exposure using CTMs is underestimated by 44 ± 4%. Particulate matter with a diameter less than 10 μm (PM10) is also underestimated, but only by 15 ± 4%. Calculation of the sub-grid covariance for the ozone health indicator SOMO35 (Sum of Ozone 8 h running Means Over 35 ppb) was not carried out for all of Europe as the sub-grid parameterisation was considered too uncertain for useful application. However, estimates based on observations alone show that population weighted SOMO35 concentrations are overestimated by around 13% when using model grid resolutions of 50 km.► We investigate the impact of sub-grid variability on air quality exposure. ► We use the sub-grid covariance of concentration and population for this. ► We use observed concentrations for the assessment. ► We develop a parameterisation that makes use of high resolution proxy data. ► We apply this to all of Europe.
Keywords: Air quality; Exposure; Sub-grid variability; Covariance
Sub-grid variability and its impact on European wide air quality exposure assessment by Bruce Denby; Massimo Cassiani; Peter de Smet; Frank de Leeuw; Jan Horálek (pp. 4220-4229).
Estimates of population exposure to air pollution on the European scale are required for policy development and health impact assessment. Long term exposure estimates of this type can be made using spatially distributed air quality and population density data. Gridded chemical transport models (CTMs) are often used for this purpose, however the grid resolution of CTMs that cover entire continents is usually limited to 25–100 km and there may be a significant level of unresolved variability within the grids that will impact on the exposure estimates. In this paper sub-grid variability and its impact on long term exposure estimates is assessed by investigating the covariance of concentration and population, which is shown to be the defining term in estimating the average sub-grid population exposure. A parameterisation of the sub-grid covariance is described, based on the sub-grid covariance of other proxy data, and this is applied using EMEP model results for all of Europe. The study shows that the error made in the exposure calculations for all of Europe is significant for the typical CTM resolution of 50 km. The error is largest for NO2, where the average European urban background exposure using CTMs is underestimated by 44 ± 4%. Particulate matter with a diameter less than 10 μm (PM10) is also underestimated, but only by 15 ± 4%. Calculation of the sub-grid covariance for the ozone health indicator SOMO35 (Sum of Ozone 8 h running Means Over 35 ppb) was not carried out for all of Europe as the sub-grid parameterisation was considered too uncertain for useful application. However, estimates based on observations alone show that population weighted SOMO35 concentrations are overestimated by around 13% when using model grid resolutions of 50 km.► We investigate the impact of sub-grid variability on air quality exposure. ► We use the sub-grid covariance of concentration and population for this. ► We use observed concentrations for the assessment. ► We develop a parameterisation that makes use of high resolution proxy data. ► We apply this to all of Europe.
Keywords: Air quality; Exposure; Sub-grid variability; Covariance
Atmospheric depositional fluxes of cosmogenic35S and7Be: Implications for the turnover rate of sulfur through the biosphere by Hyung-Mi Cho; Young-Lim Hong; Guebuem Kim (pp. 4230-4234).
The wet depositional fluxes of cosmogenic35S and7Be, together with210Pb, were measured in Seoul, Korea, from April 2004 to April 2005. Approximately half of the annual fluxes occurred in summer, during which about 60% of the precipitations occurred. Our simple box model shows that the theoretical scavenging ratio of35S/7Be to the ground is approximately 0.013, which accounts for the decay for the duration of oxidation and settling. However, we observed ∼50% higher35S/7Be activity ratios than the theoretical removal ratio over the entire sampling period, with particularly higher (∼133%) ratios during November 2004–April 2005. These higher ratios in the winter cannot be explained by sudden incursions of the stratospheric air or longer aerosol residence times, on the basis of7Be/210Pb ratios. We hypothesize that the ratios could occur owing to biomass burning or as plants go dormant and dry during the autumn and winter. Based on this hypothesis, we developed a35S/7Be mass balance model which yields the turnover rate of sulfur in the atmosphere through the biosphere to be 0.015 ± 0.007 d−1. Such a rapid sulfur turnover rate should be applied to the prediction model of sulfur inventory changes.► Annual wet depositional flux of35S was 0.17 dpm cm−2 yr−1 at the mid-latitudes. ► The rapid turnover of sulfur through the biosphere was traced using35S. ► The turnover of sulfur through the biosphere mainly occurs during autumn and winter. ► The turnover rate of sulfur is measured to be ∼0.015 d−1 based on the35S/7Be model.
Keywords: Sulfur cycle; 35; S; 7; Be; 210; Pb; Precipitation; Atmosphere
Atmospheric depositional fluxes of cosmogenic35S and7Be: Implications for the turnover rate of sulfur through the biosphere by Hyung-Mi Cho; Young-Lim Hong; Guebuem Kim (pp. 4230-4234).
The wet depositional fluxes of cosmogenic35S and7Be, together with210Pb, were measured in Seoul, Korea, from April 2004 to April 2005. Approximately half of the annual fluxes occurred in summer, during which about 60% of the precipitations occurred. Our simple box model shows that the theoretical scavenging ratio of35S/7Be to the ground is approximately 0.013, which accounts for the decay for the duration of oxidation and settling. However, we observed ∼50% higher35S/7Be activity ratios than the theoretical removal ratio over the entire sampling period, with particularly higher (∼133%) ratios during November 2004–April 2005. These higher ratios in the winter cannot be explained by sudden incursions of the stratospheric air or longer aerosol residence times, on the basis of7Be/210Pb ratios. We hypothesize that the ratios could occur owing to biomass burning or as plants go dormant and dry during the autumn and winter. Based on this hypothesis, we developed a35S/7Be mass balance model which yields the turnover rate of sulfur in the atmosphere through the biosphere to be 0.015 ± 0.007 d−1. Such a rapid sulfur turnover rate should be applied to the prediction model of sulfur inventory changes.► Annual wet depositional flux of35S was 0.17 dpm cm−2 yr−1 at the mid-latitudes. ► The rapid turnover of sulfur through the biosphere was traced using35S. ► The turnover of sulfur through the biosphere mainly occurs during autumn and winter. ► The turnover rate of sulfur is measured to be ∼0.015 d−1 based on the35S/7Be model.
Keywords: Sulfur cycle; 35; S; 7; Be; 210; Pb; Precipitation; Atmosphere
Secondary organic aerosol formation from ozone reactions with single terpenoids and terpenoid mixtures by Michael S. Waring; J. Raymond Wells; Jeffrey A. Siegel (pp. 4235-4242).
Ozone reacts with indoor-emitted terpenoids to form secondary organic aerosol (SOA). Most SOA research has focused on ozone reactions with single terpenoids or with consumer products, and this paper reports the results from an investigation of SOA formation from ozone reactions with both single terpenoids and mixtures ofd-limonene, α-pinene, and α-terpineol. Transient experiments were conducted at low (25 ppb) and high (100 ppb) initial concentrations of ozone. The three terpenoids were tested singly and in combinations in a manner that controlled for their different reaction rates with ozone. The SOA formation was assessed by examining the evolution in time of the resulting number size-distributions and estimates of the mass concentrations. The results suggest that at higher ozone and terpenoid concentrations, SOA number formation follows a linear trend as a function of the initial rate of reaction. This finding was valid for both single terpenoids and mixtures. Generally speaking, higher ozone and terpenoid concentrations also led to larger geometric mean diameters and smaller geometric standard deviations of fitted lognormal distributions of the formed SOA. By assuming a density, mass concentrations were also assessed and did not follow as consistent of a trend. At low ozone concentration conditions, reactions with onlyd-limonene yielded the largest number concentrations of any experiment, even more than experiments with mixtures containingd-limonene and much higher overall terpenoid concentrations. This finding was not seen for high ozone concentrations. These experiments demonstrate quantifiable trends for SOA forming reactions of ozone and mixtures, and this work provides a framework for expanding these results to more complex mixtures and consumer products.► Concentrations of SOA formed due to ozone and terpenoid mixtures were examined. ► SOA number formation mostly followed a linear trend with initial reaction rate. ► Higher reaction rates led to larger geometric mean diameters of distributions. ► Higher reaction rates led to lower geometric standard deviations of distributions. ► Mass formation did not follow as consistent of a trend as number formation results.
Keywords: Indoor chemistry; Ozone; D; -limonene; α-Pinene; α-Terpineol; Particle formation
Secondary organic aerosol formation from ozone reactions with single terpenoids and terpenoid mixtures by Michael S. Waring; J. Raymond Wells; Jeffrey A. Siegel (pp. 4235-4242).
Ozone reacts with indoor-emitted terpenoids to form secondary organic aerosol (SOA). Most SOA research has focused on ozone reactions with single terpenoids or with consumer products, and this paper reports the results from an investigation of SOA formation from ozone reactions with both single terpenoids and mixtures ofd-limonene, α-pinene, and α-terpineol. Transient experiments were conducted at low (25 ppb) and high (100 ppb) initial concentrations of ozone. The three terpenoids were tested singly and in combinations in a manner that controlled for their different reaction rates with ozone. The SOA formation was assessed by examining the evolution in time of the resulting number size-distributions and estimates of the mass concentrations. The results suggest that at higher ozone and terpenoid concentrations, SOA number formation follows a linear trend as a function of the initial rate of reaction. This finding was valid for both single terpenoids and mixtures. Generally speaking, higher ozone and terpenoid concentrations also led to larger geometric mean diameters and smaller geometric standard deviations of fitted lognormal distributions of the formed SOA. By assuming a density, mass concentrations were also assessed and did not follow as consistent of a trend. At low ozone concentration conditions, reactions with onlyd-limonene yielded the largest number concentrations of any experiment, even more than experiments with mixtures containingd-limonene and much higher overall terpenoid concentrations. This finding was not seen for high ozone concentrations. These experiments demonstrate quantifiable trends for SOA forming reactions of ozone and mixtures, and this work provides a framework for expanding these results to more complex mixtures and consumer products.► Concentrations of SOA formed due to ozone and terpenoid mixtures were examined. ► SOA number formation mostly followed a linear trend with initial reaction rate. ► Higher reaction rates led to larger geometric mean diameters of distributions. ► Higher reaction rates led to lower geometric standard deviations of distributions. ► Mass formation did not follow as consistent of a trend as number formation results.
Keywords: Indoor chemistry; Ozone; D; -limonene; α-Pinene; α-Terpineol; Particle formation
Identifying and tracking key odorants from cattle feedlots by Steven Trabue; Kenwood Scoggin; Laura McConnell; Ronaldo Maghirang; Edna Razote; Jerry Hatfield (pp. 4243-4251).
Odors from cattle feedlots can negatively affect air quality in local communities. Our objectives were the following: 1) identify key odor-causing compounds using odor activity values (OAVs) and gas chromatography–olfactometry (GC–O) techniques; 2) compare odor threshold values from published databases; and 3) track the movement of odors from a cattle feedlot to receptor community. Odorous compounds emitted from a cattle feedlot were sampled on-site, 250 m downwind and 3.2 km downwind using both sorbent tubes and denuders. Sorbent tubes were analyzed by both GC–MS and GC–MS–O and key odorants determined using both OAV and GC-Surface Nasal Impact Frequency (SNIF) analysis, while denuders were analyzed by ion chromatography. Odorant concentrations had a diurnal pattern with peak concentrations during early morning and late evening periods. Volatile fatty acids (VFAs) were the most abundant of the major odorants. Odorants with concentrations above their odor threshold values at the feedlot included amines, VFAs, phenol compounds, and indole compounds. Key odorants at the feedlot were VFAs and phenol compounds, but their relative importance diminished with downwind distance. Indole compounds, while not the key odorants at the feedlot, increased in relative importance downwind of the feedlot. In general, the odorous compounds identified by GC-SNIF and OAV as having fecal/manure nature were similar. GC-SNIF was the more sensitive analytical technique; it identified several compounds that may have contributed to the unpleasantness of the cattle feedlot odor, but its throughput was extremely low thereby limiting its usefulness. There is a need to improve field sampling devices and odor threshold databases to enhance understanding and confidence in evaluating odors.► Odors from feedlots were monitored using chemical and GC–O techniques. ► At the feedlot, volatile fatty acids and phenols were the key odorants. ► Downwind indole compounds become the key odorant. ► GC–O is analytically more sensitive for odors than chemical techniques. ► Odor threshold databases limited for chemical analysis of odorants.
Keywords: Air quality; CAFO; Gas chromatography–olfactometry; Odor; VOC
Identifying and tracking key odorants from cattle feedlots by Steven Trabue; Kenwood Scoggin; Laura McConnell; Ronaldo Maghirang; Edna Razote; Jerry Hatfield (pp. 4243-4251).
Odors from cattle feedlots can negatively affect air quality in local communities. Our objectives were the following: 1) identify key odor-causing compounds using odor activity values (OAVs) and gas chromatography–olfactometry (GC–O) techniques; 2) compare odor threshold values from published databases; and 3) track the movement of odors from a cattle feedlot to receptor community. Odorous compounds emitted from a cattle feedlot were sampled on-site, 250 m downwind and 3.2 km downwind using both sorbent tubes and denuders. Sorbent tubes were analyzed by both GC–MS and GC–MS–O and key odorants determined using both OAV and GC-Surface Nasal Impact Frequency (SNIF) analysis, while denuders were analyzed by ion chromatography. Odorant concentrations had a diurnal pattern with peak concentrations during early morning and late evening periods. Volatile fatty acids (VFAs) were the most abundant of the major odorants. Odorants with concentrations above their odor threshold values at the feedlot included amines, VFAs, phenol compounds, and indole compounds. Key odorants at the feedlot were VFAs and phenol compounds, but their relative importance diminished with downwind distance. Indole compounds, while not the key odorants at the feedlot, increased in relative importance downwind of the feedlot. In general, the odorous compounds identified by GC-SNIF and OAV as having fecal/manure nature were similar. GC-SNIF was the more sensitive analytical technique; it identified several compounds that may have contributed to the unpleasantness of the cattle feedlot odor, but its throughput was extremely low thereby limiting its usefulness. There is a need to improve field sampling devices and odor threshold databases to enhance understanding and confidence in evaluating odors.► Odors from feedlots were monitored using chemical and GC–O techniques. ► At the feedlot, volatile fatty acids and phenols were the key odorants. ► Downwind indole compounds become the key odorant. ► GC–O is analytically more sensitive for odors than chemical techniques. ► Odor threshold databases limited for chemical analysis of odorants.
Keywords: Air quality; CAFO; Gas chromatography–olfactometry; Odor; VOC
A five-year observation of atmospheric metals on Ulleung Island in the East/Japan Sea: Temporal variability and source identification by Jeongwon Kang; Man-Sik Choi; Hi-Il Yi; Yun-Ho Song; Dongyup Lee; Ju-Hye Cho (pp. 4252-4262).
We investigated seasonal characteristics (concentration, enrichment factors, and correlation coefficients) of chemical constituents, including sources for sea salt-corrected metals (Al, Fe, K, Ca, Mg, S, As, Cd, Co, Cu, Li, Mn, Mo, Ni, Pb, Sn, Sr, Ti, V, and Zn), in 334 aerosol samples collected during October 2003–October 2008 at Ulleung Island in the southern East/Japan Sea. High Al concentrations were found in spring (geometric means of 1.23 and 1.28 μg m−3 in March and April, respectively) due to Asian dust (yellow sand) originating from northeastern China. The dust mineral transport by strong winds resulted in a change of metal composition showing soil-dominated condition. In the rainy period (June–September), the aerosol metal concentrations and composition were influenced largely by wet deposition and the summer monsoon, together with anthropogenic aerosol transport. The correlation coefficients in the summer period (July and August) showed a positive correlation of Al with K ( r = 0.74) and As ( r = 0.63), probably reflecting anthropogenic-originated Al coming from coal burning. In autumn (October and November) and winter (December and January), mixed sources of soil and anthropogenic-originated aerosols were pronounced by the development of northwesterly winds from the Asian continent. Especially, the soil-originated proportion was relatively higher in autumn than in winter when the anthropogenic-originated aerosols from heating fuels predominated. Anthropogenic As, Sn, Mo, Zn, Pb, and Cd between low- and high-dust periods that had similar air–mass movements in spring were at similar concentrations, but higher in the air masses including eastern China trajectories and/or slow movement at lower height during high-dust periods.Display Omitted► In spring, high levels of soil-originated and anthropogenic metals were found. ► In summer, fine-sized Al originated from coal burning was transported. ► AOMs were high in the air masses from eastern China during the high-dust period.
Keywords: Asian dust; Atmospheric metals; Backward trajectory; Coal burning; East Sea; Japan Sea; Ulleung Island
A five-year observation of atmospheric metals on Ulleung Island in the East/Japan Sea: Temporal variability and source identification by Jeongwon Kang; Man-Sik Choi; Hi-Il Yi; Yun-Ho Song; Dongyup Lee; Ju-Hye Cho (pp. 4252-4262).
We investigated seasonal characteristics (concentration, enrichment factors, and correlation coefficients) of chemical constituents, including sources for sea salt-corrected metals (Al, Fe, K, Ca, Mg, S, As, Cd, Co, Cu, Li, Mn, Mo, Ni, Pb, Sn, Sr, Ti, V, and Zn), in 334 aerosol samples collected during October 2003–October 2008 at Ulleung Island in the southern East/Japan Sea. High Al concentrations were found in spring (geometric means of 1.23 and 1.28 μg m−3 in March and April, respectively) due to Asian dust (yellow sand) originating from northeastern China. The dust mineral transport by strong winds resulted in a change of metal composition showing soil-dominated condition. In the rainy period (June–September), the aerosol metal concentrations and composition were influenced largely by wet deposition and the summer monsoon, together with anthropogenic aerosol transport. The correlation coefficients in the summer period (July and August) showed a positive correlation of Al with K ( r = 0.74) and As ( r = 0.63), probably reflecting anthropogenic-originated Al coming from coal burning. In autumn (October and November) and winter (December and January), mixed sources of soil and anthropogenic-originated aerosols were pronounced by the development of northwesterly winds from the Asian continent. Especially, the soil-originated proportion was relatively higher in autumn than in winter when the anthropogenic-originated aerosols from heating fuels predominated. Anthropogenic As, Sn, Mo, Zn, Pb, and Cd between low- and high-dust periods that had similar air–mass movements in spring were at similar concentrations, but higher in the air masses including eastern China trajectories and/or slow movement at lower height during high-dust periods.Display Omitted► In spring, high levels of soil-originated and anthropogenic metals were found. ► In summer, fine-sized Al originated from coal burning was transported. ► AOMs were high in the air masses from eastern China during the high-dust period.
Keywords: Asian dust; Atmospheric metals; Backward trajectory; Coal burning; East Sea; Japan Sea; Ulleung Island
Light absorption coefficient measurement of SOA using a UV–Visible spectrometer connected with an integrating sphere by Min Zhong; Myoseon Jang (pp. 4263-4271).
A method for measuring an aerosol light absorption coefficient (B a) has been developed using a conventional UV–visible spectrometer equipped with an integrating sphere covering a wide range of wavelengths (280–800 nm). The feasibility of the proposed method was evaluated in both the transmittance mode (TUV-IS) and the reflective mode (RUV-IS) using the reference aerosol known for the cross-sectional area. The aerosol was collected on a conventional filter and measured forB a values. The resulting RUV-IS method was applied to measure light absorption of secondary organic aerosol (SOA). SOA was produced through photooxidation of different precursor hydrocarbons such as toluene, d-limonene and α-pinene in the presence of NOx (60–70 ppb) and inorganic seed aerosol using a 2-m3 indoor Teflon film chamber. Of the three precursor hydrocarbons, theB a value of toluene SOA (0.574 m2 g−1 at 350 nm) was the highest compared withB a values for α-pinene SOA (0.029 m2 g−1) and d-limonene SOA (0.038 m2 g−1). When d-limonene SOA or toluene SOA was internally mixed with neutral [(NH4)2SO4] or acidic inorganic seed (NH4HSO4:H2SO4 = 1:1 by mole), the SOA showed 2–3 times greaterB a values at 350 nm than the SOA with no seed. Aerosol aging with a light source for this study reducedB a values of SOA (e.g., on average 10% for toluene SOA and 30% for d-limonene SOA within 4 h). Overall, weak absorption appeared for chamber-generated SOA over wavelengths ranging from 280 to 550 nm, which fall into the sunlight spectrum.► UV–VIS spectrometer with an integrating sphere to measure aerosol light absorption. ► Light absorption coefficient of atmospheric organic aerosol. ► Reflective UV–Visible spectrometry feasible for aerosol filter samples.
Keywords: Light absorption coefficient; SOA; Toluene; d; -Limonene; α; -Pinene; Inorganic aerosol; Reflective UV–visible spectrometry
Light absorption coefficient measurement of SOA using a UV–Visible spectrometer connected with an integrating sphere by Min Zhong; Myoseon Jang (pp. 4263-4271).
A method for measuring an aerosol light absorption coefficient (B a) has been developed using a conventional UV–visible spectrometer equipped with an integrating sphere covering a wide range of wavelengths (280–800 nm). The feasibility of the proposed method was evaluated in both the transmittance mode (TUV-IS) and the reflective mode (RUV-IS) using the reference aerosol known for the cross-sectional area. The aerosol was collected on a conventional filter and measured forB a values. The resulting RUV-IS method was applied to measure light absorption of secondary organic aerosol (SOA). SOA was produced through photooxidation of different precursor hydrocarbons such as toluene, d-limonene and α-pinene in the presence of NOx (60–70 ppb) and inorganic seed aerosol using a 2-m3 indoor Teflon film chamber. Of the three precursor hydrocarbons, theB a value of toluene SOA (0.574 m2 g−1 at 350 nm) was the highest compared withB a values for α-pinene SOA (0.029 m2 g−1) and d-limonene SOA (0.038 m2 g−1). When d-limonene SOA or toluene SOA was internally mixed with neutral [(NH4)2SO4] or acidic inorganic seed (NH4HSO4:H2SO4 = 1:1 by mole), the SOA showed 2–3 times greaterB a values at 350 nm than the SOA with no seed. Aerosol aging with a light source for this study reducedB a values of SOA (e.g., on average 10% for toluene SOA and 30% for d-limonene SOA within 4 h). Overall, weak absorption appeared for chamber-generated SOA over wavelengths ranging from 280 to 550 nm, which fall into the sunlight spectrum.► UV–VIS spectrometer with an integrating sphere to measure aerosol light absorption. ► Light absorption coefficient of atmospheric organic aerosol. ► Reflective UV–Visible spectrometry feasible for aerosol filter samples.
Keywords: Light absorption coefficient; SOA; Toluene; d; -Limonene; α; -Pinene; Inorganic aerosol; Reflective UV–visible spectrometry
Ambient formaldehyde source attribution in Houston during TexAQS II and TRAMP by Birnur Buzcu Guven; Eduardo P. Olaguer (pp. 4272-4280).
An online data repository known as the Air Research Information Infrastructure (ARII) was used to discriminate large industrial sources of formaldehyde (HCHO) from mobile and secondary formaldehyde sources in Houston. Analysis of continuous online measurements at one urban and two industrial sites obtained during the summer of 2006 enabled us to isolate and evaluate major source factors associated with formaldehyde. The contribution of industrial sources to total atmospheric formaldehyde at the urban Houston site is estimated to be 17%, compared to 23% for mobile sources, 36% secondary formation, and 24% biogenic sources. The potential industrial sources include flares from petrochemical plants and refineries in the Port of Houston. The relative contribution of industrial source factors to ambient HCHO at the urban site increased to about 66% on some mornings, coinciding with the HCHO peak concentration. Secondary formation of HCHO during the day and night resulted from reactions of industrial olefins and other VOCs with OH or ozone. Some peak HCHO concentrations can also be linked to emission events of other VOCs, while a significant portion remains unexplained by the reported events. It is likely, based on the results from the SHARP campaign and our analysis, that some episodic emission events releasing primary HCHO are unreported to the Texas Commission on Environmental Quality (TCEQ).► We discriminated industrial sources of HCHO from mobile and secondary sources. ► The contribution of industrial sources to total atmospheric formaldehyde is 16%. ► Secondary HCHO resulted from the reactions of olefins and other VOCs with OH or O3. ► Some peak HCHO concentrations can be linked to emission events of other VOCs. ► Some episodic emission events containing HCHO are likely unreported to the TCEQ.
Keywords: Formaldehyde; Secondary formation; Industrial sources; Source apportionment; Emission events; Port of Houston
Ambient formaldehyde source attribution in Houston during TexAQS II and TRAMP by Birnur Buzcu Guven; Eduardo P. Olaguer (pp. 4272-4280).
An online data repository known as the Air Research Information Infrastructure (ARII) was used to discriminate large industrial sources of formaldehyde (HCHO) from mobile and secondary formaldehyde sources in Houston. Analysis of continuous online measurements at one urban and two industrial sites obtained during the summer of 2006 enabled us to isolate and evaluate major source factors associated with formaldehyde. The contribution of industrial sources to total atmospheric formaldehyde at the urban Houston site is estimated to be 17%, compared to 23% for mobile sources, 36% secondary formation, and 24% biogenic sources. The potential industrial sources include flares from petrochemical plants and refineries in the Port of Houston. The relative contribution of industrial source factors to ambient HCHO at the urban site increased to about 66% on some mornings, coinciding with the HCHO peak concentration. Secondary formation of HCHO during the day and night resulted from reactions of industrial olefins and other VOCs with OH or ozone. Some peak HCHO concentrations can also be linked to emission events of other VOCs, while a significant portion remains unexplained by the reported events. It is likely, based on the results from the SHARP campaign and our analysis, that some episodic emission events releasing primary HCHO are unreported to the Texas Commission on Environmental Quality (TCEQ).► We discriminated industrial sources of HCHO from mobile and secondary sources. ► The contribution of industrial sources to total atmospheric formaldehyde is 16%. ► Secondary HCHO resulted from the reactions of olefins and other VOCs with OH or O3. ► Some peak HCHO concentrations can be linked to emission events of other VOCs. ► Some episodic emission events containing HCHO are likely unreported to the TCEQ.
Keywords: Formaldehyde; Secondary formation; Industrial sources; Source apportionment; Emission events; Port of Houston
Morphological and mineralogical forms of technogenic magnetic particles in industrial dusts by T. Magiera; M. Jabłońska; Z. Strzyszcz; M. Rachwal (pp. 4281-4290).
The morphology, mineralogy, and magnetic properties of technogenic magnetic particles (TMPs) were analysed in four kinds of industrial dust produced during high temperature technological processes of different branches of industry (lignite and hard coal burning, cement production, coke production). The study was carried out by means of magnetic susceptibility measurement, energy dispersive spectroscopy (EDS), scanning electron microscope (SEM), X-ray diffraction, Mössbauer spectroscopy, and thermomagnetic analysis. To assess the total content of the magnetic fraction in bulk dust samples, mass specific magnetic susceptibility (χ) was measured and then a physical separation of magnetic particles (mostly of technogenic origin) was conducted. The dusts revealed high diversity of the χ value, which was dependent on the magnetic particles’ concentration and mineralogical composition. Significant differences in the magnetic mineralogy of dusts coming from different branches of industry were observed. In fly ashes from coal combustion, spherical forms (typical ferromagnetic spherules) of magnetite, magnesioferrite, and maghemite were mostly observed. In dusts after lignite combustion a higher content of antiferromagnetic hematite and maghemite was observed due to the lower temperature of lignite combustion. In cement dusts a large variety of iron minerals were observed including magnetite, maghemite, hematite, ferrites, and goethite. The characteristic mineral forms for cement dusts were Ca-ferrites and co-occurrence of calcite, anhydrite, gypsum, and bassanite with a magnetic mineral fraction. The magnetic fraction produced by the coke industry was mostly in the form of tightly compacted aggregates with well-formed crystal structures where ferromagnetic pyrrhotite was characteristic feature. The TMPs could be distinctive for pollution source identification and serve as a tracer of dust origin and (if found in topsoil) identification of soil pollution sources.► TMPs could be distinctive for pollution source identification. ► Magnetite or maghemite spherules are typical for hard coal ash. ► Hematite is more common in lignite ash decreasing their magnetic susceptibility. ► Metallic Fe and ferrimagnetic pyrrhotite are characteristic components of coke dust. ► Ca-ferrite is characteristic ferrimagnetic mineral for cement dust.
Keywords: Industrial dusts; Technogenic magnetic particles; Iron mineralogy; Magnetic spherules
Morphological and mineralogical forms of technogenic magnetic particles in industrial dusts by T. Magiera; M. Jabłońska; Z. Strzyszcz; M. Rachwal (pp. 4281-4290).
The morphology, mineralogy, and magnetic properties of technogenic magnetic particles (TMPs) were analysed in four kinds of industrial dust produced during high temperature technological processes of different branches of industry (lignite and hard coal burning, cement production, coke production). The study was carried out by means of magnetic susceptibility measurement, energy dispersive spectroscopy (EDS), scanning electron microscope (SEM), X-ray diffraction, Mössbauer spectroscopy, and thermomagnetic analysis. To assess the total content of the magnetic fraction in bulk dust samples, mass specific magnetic susceptibility (χ) was measured and then a physical separation of magnetic particles (mostly of technogenic origin) was conducted. The dusts revealed high diversity of the χ value, which was dependent on the magnetic particles’ concentration and mineralogical composition. Significant differences in the magnetic mineralogy of dusts coming from different branches of industry were observed. In fly ashes from coal combustion, spherical forms (typical ferromagnetic spherules) of magnetite, magnesioferrite, and maghemite were mostly observed. In dusts after lignite combustion a higher content of antiferromagnetic hematite and maghemite was observed due to the lower temperature of lignite combustion. In cement dusts a large variety of iron minerals were observed including magnetite, maghemite, hematite, ferrites, and goethite. The characteristic mineral forms for cement dusts were Ca-ferrites and co-occurrence of calcite, anhydrite, gypsum, and bassanite with a magnetic mineral fraction. The magnetic fraction produced by the coke industry was mostly in the form of tightly compacted aggregates with well-formed crystal structures where ferromagnetic pyrrhotite was characteristic feature. The TMPs could be distinctive for pollution source identification and serve as a tracer of dust origin and (if found in topsoil) identification of soil pollution sources.► TMPs could be distinctive for pollution source identification. ► Magnetite or maghemite spherules are typical for hard coal ash. ► Hematite is more common in lignite ash decreasing their magnetic susceptibility. ► Metallic Fe and ferrimagnetic pyrrhotite are characteristic components of coke dust. ► Ca-ferrite is characteristic ferrimagnetic mineral for cement dust.
Keywords: Industrial dusts; Technogenic magnetic particles; Iron mineralogy; Magnetic spherules
A linkage between Asian dust, dissolved iron and marine export production in the deep ocean by Yongxiang Han; Tianliang Zhao; Lianchun Song; Xiaomin Fang; Yan Yin; Zuqin Deng; Suping Wang; Shuxian Fan (pp. 4291-4298).
Iron-addition experiments have revealed that iron supply exerts controls on biogeochemical cycles in the ocean and ultimately influences the Earth’s climate system. The iron hypothesis in its broad outlines has been proved to be correct. However, the hypothesis needs to be verified with an observable biological response to specific dust deposition events. Plankton growth following the Asian dust storm over Ocean Station PAPA (50°N, 145°W) in the North Pacific Ocean in April 2001 was the first supportive evidence of natural aeolian iron inputs to ocean; The data were obtained through the SeaWiFS satellite and robot carbon explorers by Bishop et al. Using the NARCM modeling results in this study, the calculated total dust deposition flux was 35 mg m−2 per day in PAPA region from the dust storm of 11–13 April, 2001 into 0.0615 mg m−2 d−1 (about 1100 nM) soluble iron in the surface layer at Station PAPA. It was enough for about 1100 nM to enhance the efficiency of the marine biological pump and trigger the rapid increase of POC and chlorophyll. The iron fertilization hypothesis therefore is plausible. However, even if this specific dust event can support the iron fertilization hypothesis, long-term observation data are lacking in marine export production and continental dust. In this paper, we also conducted a simple correlation analysis between the diatoms and foraminifera at about 3000 m and 4000 m at two subarctic Pacific stations and the dust aerosol production from China’s mainland. The correlation coefficient between marine export production and dust storm frequency in the core area of the dust storms was significantly high, suggesting that aerosols generated by Asian dust storm are the source of iron for organic matter fixation in the North Pacific Ocean. These results suggest that there could be an interlocking chain for the change of atmospheric dust aerosol–soluble iron–marine export production.► Asian dust deposition flux of 35 mg m−2day−1 was simulated in the subarctic Pacific. ► Aerosols from Asian dust storm are the iron sources for organic matter fixation. ► The deep Pacific diatoms and foraminifera are correlated with Asian dust production. ► A chain interlocks for Asian dust aerosols, soluble iron and marine export production.
Keywords: Marine export production; Dust aerosol; Iron fertilizer effect; Dust deposition flux; North Pacific Ocean
A linkage between Asian dust, dissolved iron and marine export production in the deep ocean by Yongxiang Han; Tianliang Zhao; Lianchun Song; Xiaomin Fang; Yan Yin; Zuqin Deng; Suping Wang; Shuxian Fan (pp. 4291-4298).
Iron-addition experiments have revealed that iron supply exerts controls on biogeochemical cycles in the ocean and ultimately influences the Earth’s climate system. The iron hypothesis in its broad outlines has been proved to be correct. However, the hypothesis needs to be verified with an observable biological response to specific dust deposition events. Plankton growth following the Asian dust storm over Ocean Station PAPA (50°N, 145°W) in the North Pacific Ocean in April 2001 was the first supportive evidence of natural aeolian iron inputs to ocean; The data were obtained through the SeaWiFS satellite and robot carbon explorers by Bishop et al. Using the NARCM modeling results in this study, the calculated total dust deposition flux was 35 mg m−2 per day in PAPA region from the dust storm of 11–13 April, 2001 into 0.0615 mg m−2 d−1 (about 1100 nM) soluble iron in the surface layer at Station PAPA. It was enough for about 1100 nM to enhance the efficiency of the marine biological pump and trigger the rapid increase of POC and chlorophyll. The iron fertilization hypothesis therefore is plausible. However, even if this specific dust event can support the iron fertilization hypothesis, long-term observation data are lacking in marine export production and continental dust. In this paper, we also conducted a simple correlation analysis between the diatoms and foraminifera at about 3000 m and 4000 m at two subarctic Pacific stations and the dust aerosol production from China’s mainland. The correlation coefficient between marine export production and dust storm frequency in the core area of the dust storms was significantly high, suggesting that aerosols generated by Asian dust storm are the source of iron for organic matter fixation in the North Pacific Ocean. These results suggest that there could be an interlocking chain for the change of atmospheric dust aerosol–soluble iron–marine export production.► Asian dust deposition flux of 35 mg m−2day−1 was simulated in the subarctic Pacific. ► Aerosols from Asian dust storm are the iron sources for organic matter fixation. ► The deep Pacific diatoms and foraminifera are correlated with Asian dust production. ► A chain interlocks for Asian dust aerosols, soluble iron and marine export production.
Keywords: Marine export production; Dust aerosol; Iron fertilizer effect; Dust deposition flux; North Pacific Ocean
Experimental investigation of the impact of airborne dust deposition on the performance of solar photovoltaic (PV) modules by Hai Jiang; Lin Lu; Ke Sun (pp. 4299-4304).
Deposition of airborne dust on outdoor photovoltaic (PV) modules may decrease the transmittance of solar cell glazing and cause a significant degradation of solar conversion efficiency of PV modules. Previous studies of this issue indicated that dust deposition is closely related to the tilt angle of solar collector, exposure period, site climate conditions, wind movement and dust properties. However, few studies considered the influence of the properties of PV module itself on dust deposition and efficiency degradation, such as the cell types and surface materials. This experimental work aimed to study the dust accumulation onto different types of solar PV modules and the corresponding efficiency degradation. The experiment was designed and conducted in the laboratory with a sun simulator and a test chamber. The degradation of PV module efficiency caused by dust deposition under various conditions was investigated. The results indicated that dust pollution has a significant impact on PV module output. With dust deposition density increasing from 0 to 22 g m−2, the corresponding reduction of PV output efficiency grew from 0 to 26%. The reduction of efficiency has a linear relationship with the dust deposition density, and the difference caused by cell types was not obvious. When the dust deposition density was fixed, the reductions of output efficiency at relatively lower or higher solar densities were much more severe. Moreover, the surface material may influence dust deposition and accumulation considerably. The poly-crystalline silicon module packaged with epoxy degraded faster than other modules with glass surface under the same dust concentration.► Dust impact was tested. ► Deposition decreased short circuit current. ► PV efficiency reduced linearly with deposition density.
Keywords: Dust deposition; Photovoltaic modules; Efficiency reduction; Surface material
Experimental investigation of the impact of airborne dust deposition on the performance of solar photovoltaic (PV) modules by Hai Jiang; Lin Lu; Ke Sun (pp. 4299-4304).
Deposition of airborne dust on outdoor photovoltaic (PV) modules may decrease the transmittance of solar cell glazing and cause a significant degradation of solar conversion efficiency of PV modules. Previous studies of this issue indicated that dust deposition is closely related to the tilt angle of solar collector, exposure period, site climate conditions, wind movement and dust properties. However, few studies considered the influence of the properties of PV module itself on dust deposition and efficiency degradation, such as the cell types and surface materials. This experimental work aimed to study the dust accumulation onto different types of solar PV modules and the corresponding efficiency degradation. The experiment was designed and conducted in the laboratory with a sun simulator and a test chamber. The degradation of PV module efficiency caused by dust deposition under various conditions was investigated. The results indicated that dust pollution has a significant impact on PV module output. With dust deposition density increasing from 0 to 22 g m−2, the corresponding reduction of PV output efficiency grew from 0 to 26%. The reduction of efficiency has a linear relationship with the dust deposition density, and the difference caused by cell types was not obvious. When the dust deposition density was fixed, the reductions of output efficiency at relatively lower or higher solar densities were much more severe. Moreover, the surface material may influence dust deposition and accumulation considerably. The poly-crystalline silicon module packaged with epoxy degraded faster than other modules with glass surface under the same dust concentration.► Dust impact was tested. ► Deposition decreased short circuit current. ► PV efficiency reduced linearly with deposition density.
Keywords: Dust deposition; Photovoltaic modules; Efficiency reduction; Surface material
Wet deposition and scavenging efficiency of gaseous and particulate phase polycyclic aromatic compounds at a central European suburban site by Lenka Škrdlíková; Linda Landlová; Jana Klánová; Gerhard Lammel (pp. 4305-4312).
The concentration of 15 3–6-ring polycyclic aromatic hydrocarbons (PAHs) in atmospheric precipitation was monitored over 18 months in the years 2006–2008, using an automatic wet-only sampler at a suburban site in Brno, Czech Republic. The PAH concentration in rainwater varied between 2.8 and 571 ng L−1 and the volume weighted mean was 93 ng L−1 with fluoranthene, pyrene, phenanthrene and benzo(b)fluoranthene contributing most. The contribution of particle-associated PAH (sum of 15) to the wet deposition flux was by average 51%, 82% in summer and 47% in winter. The median total (gas and particulate) scavenging ratios,W t (m3 L−1), varied between 450 for acenaphthene and 3.1 × 104 for fluoranthene. Estimates of the scavenged fraction in the column of air subject to precipitation suggest that typically only a few percent or less of the airborne PAHs are washed out during a precipitation event. The contribution of particle scavenging to total PAH scavenging varied between 7 and 98% among events. Its median was 41%. Scavenging efficiency seems to be influenced by mass size distribution. It is concluded that wet deposition of PAHs is less efficient than dry deposition.► The PAH concentration in rainwater was determined at a suburban site during all seasons. ► Particle-associated and dissolved PAH contributed equal amounts to the wet deposition. ► The scavenged fraction was estimated by sampling air before rain. ► Only a few percent or less of the airborne PAHs are washed out during a precipitation event. ► Wet deposition of PAHs is less efficient than dry deposition.
Keywords: Wet deposition; Scavenging; Rainwater pollution; PAH
Wet deposition and scavenging efficiency of gaseous and particulate phase polycyclic aromatic compounds at a central European suburban site by Lenka Škrdlíková; Linda Landlová; Jana Klánová; Gerhard Lammel (pp. 4305-4312).
The concentration of 15 3–6-ring polycyclic aromatic hydrocarbons (PAHs) in atmospheric precipitation was monitored over 18 months in the years 2006–2008, using an automatic wet-only sampler at a suburban site in Brno, Czech Republic. The PAH concentration in rainwater varied between 2.8 and 571 ng L−1 and the volume weighted mean was 93 ng L−1 with fluoranthene, pyrene, phenanthrene and benzo(b)fluoranthene contributing most. The contribution of particle-associated PAH (sum of 15) to the wet deposition flux was by average 51%, 82% in summer and 47% in winter. The median total (gas and particulate) scavenging ratios,W t (m3 L−1), varied between 450 for acenaphthene and 3.1 × 104 for fluoranthene. Estimates of the scavenged fraction in the column of air subject to precipitation suggest that typically only a few percent or less of the airborne PAHs are washed out during a precipitation event. The contribution of particle scavenging to total PAH scavenging varied between 7 and 98% among events. Its median was 41%. Scavenging efficiency seems to be influenced by mass size distribution. It is concluded that wet deposition of PAHs is less efficient than dry deposition.► The PAH concentration in rainwater was determined at a suburban site during all seasons. ► Particle-associated and dissolved PAH contributed equal amounts to the wet deposition. ► The scavenged fraction was estimated by sampling air before rain. ► Only a few percent or less of the airborne PAHs are washed out during a precipitation event. ► Wet deposition of PAHs is less efficient than dry deposition.
Keywords: Wet deposition; Scavenging; Rainwater pollution; PAH
Impact of Asian dust events on airborne bacterial community assessed by molecular analyses by Eun Mi Jeon; Heung Joo Kim; Kweon Jung; Joo Hyung Kim; Min Young Kim; Yong Pyo Kim; Jong-Ok Ka (pp. 4313-4321).
Impact of Asian dust events (ADE) on atmospheric bacterial communities was studied using both cultivation and culture-independent methods. In addition, size-segregated aerosol mass concentrations and their chemical compositions were measured and backward trajectory analysis was performed. During the days affected by ADE, culturable bacterial population levels showed significant positive correlations with total suspended particles (TSP) and particulate matter with aerodynamic diameter<10μm (PM10), whereas no significant correlation was found during non-Asian dust (NAD) days. Asian dust seemed to directly impact the airborne bacterial communities, as abrupt changes of denaturing gradient gel electrophoresis (DGGE)-band patterns and significant differences in the 16S rDNA clone library between ADE and NAD days were observed. In addition, the changes of DGGE patterns were in agreement with the shift of PM2.5 chemical composition, suggesting that the outdoor bacterial community was affected by the source and transport pathways of air masses. The isolation sources of clone libraries reflected the sampled air mass transport pathways, which were simulated by backward trajectories. The results of this study revealed that the airborne culturable bacterial concentration was significantly increased and the ambient bacterial community structure was abruptly changed during ADE.► Airborne culturable bacterial concentration was increased during Asian dust events. ►Abrupt shift of DGGE patterns from non-Asian dust day to Asia dust day were observed. ► Changes of DGGE patterns coincided with the shift of PM2.5 chemical composition. ► Isolation sources of clone libraries reflected the air mass transport pathways.
Keywords: Ambient culturable bacteria; Bacterial loading factor; DGGE; 16S rDNA clone library; Principal component analysis
Impact of Asian dust events on airborne bacterial community assessed by molecular analyses by Eun Mi Jeon; Heung Joo Kim; Kweon Jung; Joo Hyung Kim; Min Young Kim; Yong Pyo Kim; Jong-Ok Ka (pp. 4313-4321).
Impact of Asian dust events (ADE) on atmospheric bacterial communities was studied using both cultivation and culture-independent methods. In addition, size-segregated aerosol mass concentrations and their chemical compositions were measured and backward trajectory analysis was performed. During the days affected by ADE, culturable bacterial population levels showed significant positive correlations with total suspended particles (TSP) and particulate matter with aerodynamic diameter<10μm (PM10), whereas no significant correlation was found during non-Asian dust (NAD) days. Asian dust seemed to directly impact the airborne bacterial communities, as abrupt changes of denaturing gradient gel electrophoresis (DGGE)-band patterns and significant differences in the 16S rDNA clone library between ADE and NAD days were observed. In addition, the changes of DGGE patterns were in agreement with the shift of PM2.5 chemical composition, suggesting that the outdoor bacterial community was affected by the source and transport pathways of air masses. The isolation sources of clone libraries reflected the sampled air mass transport pathways, which were simulated by backward trajectories. The results of this study revealed that the airborne culturable bacterial concentration was significantly increased and the ambient bacterial community structure was abruptly changed during ADE.► Airborne culturable bacterial concentration was increased during Asian dust events. ►Abrupt shift of DGGE patterns from non-Asian dust day to Asia dust day were observed. ► Changes of DGGE patterns coincided with the shift of PM2.5 chemical composition. ► Isolation sources of clone libraries reflected the air mass transport pathways.
Keywords: Ambient culturable bacteria; Bacterial loading factor; DGGE; 16S rDNA clone library; Principal component analysis
Trapping efficiency of 1,3-dichloropropene isomers by XAD-4 sorbent tubes for air sampling by S. Gao; T. Pflaum; R. Qin (pp. 4322-4327).
Emission monitoring is necessary to evaluate the impact of air pollutants such as soil fumigants on the environment. Quantifying fumigant emissions often involves the use of air sampling tubes filled with sorbents to trap fumigants. 1,3-dichloropropene (1,3-D) and chloropicrin (CP) are being increasingly used in combination in soil fumigation since the phase-out of methyl bromide. Charcoal and XAD-4 resins are used for trapping 1,3-D and CP, respectively. If one sampling tube can trap both chemicals, the number of samples, the amount of work, and associated costs can be significantly reduced. The objective of this research was to determine the efficiency of XAD-4 sorbent tubes for trapping cis- and trans-1,3-D isomers as a function of flow rate (100–1000 ml min−1) and sampling time period (10–360 min). The results showed that XAD-4 could trap both 1,3-D isomers as efficiently as charcoal, but breakthrough occurred depending on the amount of sorbent materials in a tube, fumigant amount, flow rate and sampling time period. No significant breakthrough was observed from either small (120 mg) or large (600 mg) XAD-4 sorbent tubes over short sampling time periods (≤30 min) at any flow rate. Longer sampling period at low flow rates (100 ml min−1) resulted in ≥50% breakthrough from the small tubes during a 3 h sampling period; but no remarkable breakthrough from the large XAD-4 tubes up to 6 h sampling period when 3.0 mg 1,3-D isomers were tested. Field data showed agreement with laboratory tests. At high flow rates (1000 ml min−1), >40% breakthrough was observed from large XAD-4 sorbent tubes during 3 h trapping tests suggesting that short sampling time intervals are necessary to avoid potential breakthrough of fumigants from the sampling tubes.► One air sampling tube for trapping two chemicals from a fumigant product is desired. ► Effectively trapping chloropicrin, XAD-4 was tested for trapping 1,3-dichloropropene. ► Small tubes recover >90% at any flow rates for short sampling periods (5–30 min). ► Long (3–6 h) sampling at <200 ml min−1 requires large tubes to avoid breakthrough. ► At 1000 ml min-1, long sampling periods show a potential breakthrough in large tubes.
Keywords: Soil fumigants; Emissions; Volatile organic compounds
Trapping efficiency of 1,3-dichloropropene isomers by XAD-4 sorbent tubes for air sampling by S. Gao; T. Pflaum; R. Qin (pp. 4322-4327).
Emission monitoring is necessary to evaluate the impact of air pollutants such as soil fumigants on the environment. Quantifying fumigant emissions often involves the use of air sampling tubes filled with sorbents to trap fumigants. 1,3-dichloropropene (1,3-D) and chloropicrin (CP) are being increasingly used in combination in soil fumigation since the phase-out of methyl bromide. Charcoal and XAD-4 resins are used for trapping 1,3-D and CP, respectively. If one sampling tube can trap both chemicals, the number of samples, the amount of work, and associated costs can be significantly reduced. The objective of this research was to determine the efficiency of XAD-4 sorbent tubes for trapping cis- and trans-1,3-D isomers as a function of flow rate (100–1000 ml min−1) and sampling time period (10–360 min). The results showed that XAD-4 could trap both 1,3-D isomers as efficiently as charcoal, but breakthrough occurred depending on the amount of sorbent materials in a tube, fumigant amount, flow rate and sampling time period. No significant breakthrough was observed from either small (120 mg) or large (600 mg) XAD-4 sorbent tubes over short sampling time periods (≤30 min) at any flow rate. Longer sampling period at low flow rates (100 ml min−1) resulted in ≥50% breakthrough from the small tubes during a 3 h sampling period; but no remarkable breakthrough from the large XAD-4 tubes up to 6 h sampling period when 3.0 mg 1,3-D isomers were tested. Field data showed agreement with laboratory tests. At high flow rates (1000 ml min−1), >40% breakthrough was observed from large XAD-4 sorbent tubes during 3 h trapping tests suggesting that short sampling time intervals are necessary to avoid potential breakthrough of fumigants from the sampling tubes.► One air sampling tube for trapping two chemicals from a fumigant product is desired. ► Effectively trapping chloropicrin, XAD-4 was tested for trapping 1,3-dichloropropene. ► Small tubes recover >90% at any flow rates for short sampling periods (5–30 min). ► Long (3–6 h) sampling at <200 ml min−1 requires large tubes to avoid breakthrough. ► At 1000 ml min-1, long sampling periods show a potential breakthrough in large tubes.
Keywords: Soil fumigants; Emissions; Volatile organic compounds