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Atmospheric Environment (v.44, #11)
The impact of CO2 capture in the power and heat sector on the emission of SO2, NOx, particulate matter, volatile organic compounds and NH3 in the European Union by Joris Koornneef; Andrea Ramirez; Toon van Harmelen; Arjan van Horssen; Wim Turkenburg; Andre Faaij (pp. 1369-1385).
This study quantifies the trade-offs and synergies between climate and air quality policy objectives for the European power and heat (P&H) sector. An overview is presented of the expected performance data of CO2 capture systems implemented at P&H plants, and the expected emission of key air pollutants, being: SO2, NOX, NH3, volatile organic compounds (VOCs) and particulate matter (PM). The CO2 capture systems investigated include: post-combustion, oxyfuel combustion and pre-combustion capture.For all capture systems it was found that SO2, NOx and PM emissions are expected to be reduced or remain equal per unit of primary energy input compared to power plants without CO2 capture. Increase in primary energy input as a result of the energy penalty for CO2 capture may for some technologies and substances result in a net increase of emissions per kWh output. The emission of ammonia may increase by a factor of up to 45 per unit of primary energy input for post-combustion technologies. No data are available about the emission of VOCs from CO2 capture technologies.A simple model was developed and applied to analyse the impact of CO2 capture in the European P&H sector on the emission level of key air pollutants in 2030. Four scenarios were developed: one without CO2 capture and three with one dominantly implemented CO2 capture system, varying between: post-combustion, oxyfuel combustion and pre-combustion.The results showed a reduction in GHG emissions for the scenarios with CO2 capture compared to the baseline scenario between 12% and 20% in the EU 27 region in 2030. NOx emissions were 15% higher in the P&H sector in a scenario with predominantly post-combustion and lower when oxyfuel combustion (−16%) or pre-combustion (−20%) were implemented on a large scale. Large scale implementation of the post-combustion technology in 2030 may also result in significantly higher, i.e. increase by a factor of 28, NH3 emissions compared to scenarios with other CO2 capture options or without capture. SO2 emissions were very low for all scenarios that include large scale implementation of CO2 capture in 2030, i.e. a reduction varying between 27% and 41%. Particulate Matter emissions were found to be lower in the scenarios with CO2 capture. The scenario with implementation of the oxyfuel technology showed the lowest PM emissions followed by the scenario with a significant share allocated to pre-combustion, respectively −59% and −31%. The scenario with post-combustion capture resulted in PM emissions varying between 35% reduction and 26% increase.
Keywords: CO; 2; capture and storage; Air quality; National Emission Ceiling Directive; Air pollutantsAbbreviations; CCQ; carbon capture quotient; CCS; carbon capture and storage; ESP; electrostatic precipitator; FGR; flue gas recycling; GC; gas cycle; GHG; greenhouse gas; Gt; giga tonne; IGCC; Integrated Gasification Combined Cycle; kt; kilo tonne; Mt; mega tonne; NECD; National Emission Ceiling Directive; NGCC; Natural Gas Combined Cycle; P&H; power and heat; PC; pulverised coal; PM; particulate matter; PP; power plant; SOFC (+GT); solid oxide fuel cell (+gas turbine); TSP; total suspended particulates; VOCs; volatile organic compounds
DEARS particulate matter relationships for personal, indoor, outdoor, and central site settings for a general population by Charles E. Rodes; Phil A. Lawless; Jonathan W. Thornburg; Ronald W. Williams; Carry W. Croghan (pp. 1386-1399).
This analysis provides the initial summary of PM2.5 mass concentrations relationships for all seasons and participants for a general population in the Detroit Exposure and Aerosol Research Study (DEARS). The summary presented highlights the utility of the new methodologies applied, in addition to summarizing the particulate matter (PM) data.Results include the requirement to adjust the exposure data for monitor wearing compliance and measured environmental tobacco smoke (ETS) levels, even though the study design specified a non-smoking household. A 40% wearing compliance acceptance level was suggested as necessary to balance minimizing exposure misclassification (from poor compliance) and having sufficient data to conduct robust statistical analyses. An ETS threshold level equivalent to adding more than 1.5 μg m−3 to the collected sample was found to be necessary to detect changes in the personal exposure factor ( Fpex). It is not completely clear why such a large threshold level was necessary.Statistically significant spatial PM2.5 gradients were identified in three of the six DEARS neighborhoods in Wayne County. These were expected, given the number of strong, localized PM sources in the Detroit (Michigan) metro area. Some residential outdoor bias levels compared with the central site at Allen Park exceeded 15%. After adjusting for ETS biases, the outdoor contributions to the personal exposure were typically larger by factors from 1.75 to 2.2 compared with those of the non-outdoor sources. The outdoor contribution was larger in the summer than in the winter, which is consistent with the fractions of time spent outdoors in the summer vs. the winter (6.7% vs. 1.1% of the time).Mean personal PM2.5 cloud levels for the general population DEARS cohort ranged from 1.5 to 3.8 (after ETS adjustment) and were comparable to those reported previously. The personal exposure collections indoors were typically at least 13 times greater than those contributed outdoors.
Keywords: Particulate; Exposure; Personal; Compliance; Smoking
Influence of ship emissions on air quality and input of contaminants in southern Alaska National Parks and Wilderness Areas during the 2006 tourist season by Nicole Mölders; Stacy E. Porter; Catherine F. Cahill; Georg A. Grell (pp. 1400-1413).
The impact of ship emissions on air quality in Alaska National Parks and Wilderness Areas was investigated using the Weather Research and Forecasting model inline coupled with chemistry (WRF/Chem). The visibility and deposition of atmospheric contaminants was analyzed for the length of the 2006 tourist season. WRF/Chem reproduced the meteorological situation well. It seems to have captured the temporal behavior of aerosol concentrations when compared with the few data available. Air quality follows certain predetermined patterns associated with local meteorological conditions and ship emissions. Ship emissions have maximum impacts in Prince William Sound where topography and decaying lows trap pollutants. Along sea-lanes and adjacent coastal areas, NOx, SO2, O3, PAN, HNO3, and PM2.5 increase up to 650 pptv, 325 pptv, 900 pptv, 18 pptv, 10 pptv, and 100 ng m−3. Some of these increases are significant (95% confidence). Enhanced particulate matter concentrations from ship emissions reduce visibility up to 30% in Prince William Sound and 5–25% along sea-lanes.
Keywords: WRF/Chem; Ship emissions; Pollution; Bottom–up ship-emission inventory
A contribution of brown carbon aerosol to the aerosol light absorption and its radiative forcing in East Asia by Rokjin J. Park; Minjoong J. Kim; Jaein I. Jeong; Daeok Youn; Sangwoo Kim (pp. 1414-1421).
Brown carbon aerosols were recently found to be ubiquitous and effectively absorb solar radiation. We use a 3-D global chemical transport model (GEOS-Chem) together with aircraft and ground based observations from the TRACE-P and the ACE-Asia campaigns to examine the contribution of brown carbon aerosol to the aerosol light absorption and its climatic implication over East Asia in spring 2001. We estimated brown carbon aerosol concentrations in the model using the mass ratio of brown carbon to black carbon (BC) aerosols based on measurements in China and Europe. The comparison of simulated versus observed aerosol light absorption showed that the model accounting for brown carbon aerosol resulted in a better agreement with the observations in East Asian-Pacific outflow. We then used the model results to compute the radiative forcing of brown carbon, which amounts up to −2.4 W m−2 and 0.24 W m−2 at the surface and at the top of the atmosphere (TOA), respectively, over East Asia. Mean radiative forcing of brown carbon aerosol is −0.43 W m−2 and 0.05 W m−2 at the surface and at the TOA, accounting for about 15% of total radiative forcing (−2.2 W m−2 and 0.33 W m−2) by absorbing aerosols (BC + brown carbon aerosol), having a significant climatic implication in East Asia.
Keywords: Chemical transport model; Black carbon aerosol; Brown carbon aerosol; Radiative forcing; East Asia; Regional climate
Aerosol transport model evaluation of an extreme smoke episode in Southeast Asia by Edward J. Hyer; Boon Ning Chew (pp. 1422-1427).
Biomass burning is one of many sources of particulate pollution in Southeast Asia, but its irregular spatial and temporal patterns mean that large episodes can cause acute air quality problems in urban areas. Fires in Sumatra and Borneo during September and October 2006 contributed to 24-h mean PM10 concentrations above 150 μg m−3 at multiple locations in Singapore and Malaysia over several days. We use the FLAMBE model of biomass burning emissions and the NAAPS model of aerosol transport and evolution to simulate these events, and compare our simulation results to 24-h average PM10 measurements from 54 stations in Singapore and Malaysia. The model simulation, including the FLAMBE smoke source as well as dust, sulfate, and sea salt aerosol species, was able to explain 50% or more of the variance in 24-h PM10 observations at 29 of 54 sites. Simulation results indicated that biomass burning smoke contributed to nearly all of the extreme PM10 observations during September–November 2006, but the exact contribution of smoke was unclear because the model severely underestimated total smoke emissions. Using regression analysis at each site, the bias in the smoke aerosol flux was determined to be a factor of between 2.5 and 10, and an overall factor of 3.5 was estimated. After application of this factor, the simulated smoke aerosol concentration averaged 20% of observed PM10, and 40% of PM10 for days with 24-h average concentrations above 150 μg m−3. These results suggest that aerosol transport models can aid analysis of severe pollution events in Southeast Asia, but that improvements are needed in models of biomass burning smoke emissions.
Keywords: Biomass burning; Fire; Malaysia; Indonesia; Singapore; Aerosol; Aerosol transport modeling; Aerosol modeling; Emissions modeling; Smoke; Smoke emissions; Sumatra; Borneo
Predicting logarithmic values of the subcooled liquid vapor pressure of halogenated persistent organic pollutants with QSPR: How different are chlorinated and brominated congeners? by Agnieszka Gajewicz; Maciej Haranczyk; Tomasz Puzyn (pp. 1428-1436).
Logarithmic values of the subcooled liquid vapor pressure (log PL) were estimated for 1436 polychlorinated and polybrominated congeners of benzenes, biphenyls, dibenzo- p-dioxins, dibenzofurans, diphenyl ethers and naphthalenes by employing the Quantitative Structure–Property Relationships (QSPR) approach. The QSPR model developed with GA–PLS technique was characterized by satisfactory goodness-of-fit, robustness and the external predictive performance (R2Y = 0.970, QCV2 = 0.970, QExt2 = 0.966, RMSEC = 0.21, RMSECV = 0.22 and RMSEP = 0.22). The externally validated model has been applied to predict subcooled liquid vapor pressure of uninvestigated halogenated persistent organic pollutants. Moreover, a simple arithmetic relationship between logarithmic values of subcooled liquid vapor pressures in pairs of chloro- and bromo-analogues has been found. This relationship can be used for estimating log PL of a brominated compound, whenever log PL of its chlorinated counterpart is known, without necessity of performing any time-consuming computations.
Keywords: Brominated POPs; Vapor pressure; QSPR
Air pollutants and health outcomes: Assessment of confounding by influenza by Thuan-Quoc Thach; Chit-Ming Wong; King-Pan Chan; Yuen-Kwan Chau; G. Neil Thomas; Chun-Quan Ou; Lin Yang; Joseph S.M. Peiris; Tai-Hing Lam; Anthony J. Hedley (pp. 1437-1442).
We assessed confounding of associations between short-term effects of air pollution and health outcomes by influenza using Hong Kong mortality and hospitalization data for 1996–2002.Three measures of influenza were defined: (i) intensity: weekly proportion of positive influenza viruses, (ii) epidemic: weekly number of positive influenza viruses ≥4% of the annual number for ≥2 consecutive weeks, and (iii) predominance: an epidemic period with co-circulation of respiratory syncytial virus <2% of the annual positive isolates for ≥2 consecutive weeks. We examined effects of influenza on associations between nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with aerodynamic diameter ≤10 μm (PM10) and ozone (O3) and health outcomes including all natural causes mortality, cardiorespiratory mortality and hospitalization. Generalized additive Poisson regression model with natural cubic splines was fitted to control for time-varying covariates to estimate air pollution health effects. Confounding with influenza was assessed using an absolute difference of >0.1% between unadjusted and adjusted excess risks (ER%).Without adjustment, pollutants were associated with positive ER% for all health outcomes except asthma and stroke hospitalization with SO2 and stroke hospitalization with O3. Following adjustment, changes in ER% for all pollutants were <0.1% for all natural causes mortality, but >0.1% for mortality from stroke with NO2 and SO2, cardiac or heart disease with NO2, PM10 and O3, lower respiratory infections with NO2 and O3 and mortality from chronic obstructive pulmonary disease with all pollutants. Changes >0.1% were seen for acute respiratory disease hospitalization with NO2, SO2 and O3 and acute lower respiratory infections hospitalization with PM10. Generally, influenza does not confound the observed associations of air pollutants with all natural causes mortality and cardiovascular hospitalization, but for some pollutants and subgroups of cardiorespiratory mortality and respiratory hospitalization there was evidence to suggest confounding by influenza.
Keywords: Confounding; Influenza activity; Mortality; Hospitalization; Hong KongAbbreviations; ALRI; acute lower respiratory infections; ARD; acute respiratory; CI; confidence interval; COPD; chronic obstructive pulmonary disease; ER%; excess risk in percent; HD; heart disease; IHD; ischemic heart disease; ICD-9; International Classification of Diseases, 9th Revision; ICD-10; International Classification of Diseases, 10th Revision; LRI; lower respiratory diseases; μg m; −3; microgram per cubic meter; μm; micron; NO; 2; nitrogen dioxide; O; 3; ozone; PM; 10; particulate matter with an aerodynamic diameter ≤10 μm; RSV; respiratory syncytial viruses; SO; 2; sulfur dioxide
The impact of the 2005 Gulf hurricanes on pollution emissions as inferred from Ozone Monitoring Instrument (OMI) nitrogen dioxide by Yasuko Yoshida; Bryan N. Duncan; Christian Retscher; Kenneth E. Pickering; Edward A. Celarier; Joanna Joiner; K. Folkert Boersma; J. Pepijn Veefkind (pp. 1443-1448).
The impact of Hurricanes Katrina and Rita in 2005 on pollution emissions in the Gulf of Mexico region was investigated using tropospheric column amounts of nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) on the NASA Aura satellite. Around New Orleans and coastal Mississippi, we estimate that Katrina caused a 35% reduction in NOx emissions on average in the three weeks after landfall. Hurricane Rita caused a significant reduction (20%) in NOx emissions associated with power generation and intensive oil refining activities near the Texas/Louisiana border. We also found a 43% decrease by these two storms over the eastern Gulf of Mexico Outer Continental Shelf mainly due to the evacuation of and damage to platforms, rigs, and ports associated with oil and natural gas production.
Keywords: Pollution emissions; Hurricanes; OMI; Tropospheric NO; 2
Measurement of real time black carbon for investigating spot loading effects of Aethalometer data by Seung Shik Park; Anthony D.A. Hansen; Sung Y. Cho (pp. 1449-1455).
Measurements of real-time continuous PM2.5 black carbon (BC) concentrations were made using a single-wavelength Aethalometer (@880 nm) in three different environments, i.e., an indoor office, a residential indoor living room and an urban site, to evaluate the difference in temporal behaviors of BC particles and investigate the optical shadowing effect in the Aethalometer BC data. An empirical method was used for correcting the optical saturation effect on the original BC data obtained from the measurements at the three sites. Also, the elemental carbon (EC) concentrations from 24-h filter-based measurements of PM2.5 particles were determined using a thermal optical transmittance (TOT) method at the same urban site for comparison with the Aethalometer BC results. Transient events of BC were often observed for period of a few hours at all sites, reaching a maximum level of 27.3 μg m−3 at the urban site. The diurnal cycles of the BC concentrations observed at the two indoor environments were found to be considerably affected by the air exchange rate, occupants' behavior patterns and nearby traffic emissions. The time-series plots of the Aethalometer data showed obvious discontinuities at the filter spot change, and a rise in the apparent BC concentrations after filter tape advances. Also, the relationship between the attenuation and BC concentration was found to be non-linear at all sites. The empirical approach presented here demonstrated a definite improvement in the continuity of the BC data across the time gaps of each tape advance. The compensated BC concentration was 1.10–1.23 times greater than the raw BC data, depending on the observation sites, with the highest difference observed between the raw and compensated BC data at an indoor office near a small traffic road. The 24-h integrated EC concentration was approximately 12% higher than the original 24-h average BC concentration and 6% lower than the loading compensated BC concentration, showing that the loading compensation process accounted for the saturation effect of the filter tape.
Keywords: Black carbon; Optical loading effect; Attenuation; Indoor office; Residential living room
Improved land cover and emission factors for modeling biogenic volatile organic compounds emissions from Hong Kong by D.Y.C. Leung; P. Wong; B.K.H. Cheung; A. Guenther (pp. 1456-1468).
This paper describes a study of local biogenic volatile organic compounds (BVOC) emissions from the Hong Kong Special Administrative Region (HKSAR). An improved land cover and emission factor database was developed to estimate Hong Kong emissions using MEGAN, a BVOC emission model developed by . Field surveys of plant species composition and laboratory measurements of emission factors were combined with other data to improve existing land cover and emission factor data. The BVOC emissions from Hong Kong were calculated for 12 consecutive years from 1995 to 2006. For the year 2006, the total annual BVOC emissions were determined to be 12,400 metric tons or 9.82 × 109 g C (BVOC carbon). Isoprene emission accounts for 72%, monoterpene emissions account for 8%, and other VOCs emissions account for the remaining 20%. As expected, seasonal variation results in a higher emission in the summer and a lower emission in the winter, with emission predominantly in day time. A high emission of isoprene occurs for regions, such as Lowest Forest-NT North, dominated by broadleaf trees. The spatial variation of total BVOC is similar to the isoprene spatial variation due to its high contribution. The year to year variability in emissions due to weather was small over the twelve-year period (−1.4%, 2006 to 1995 trendline), but an increasing trend in the annual variation due to an increase in forest land cover can be observed (+7%, 2006 to 1995 trendline). The results of this study demonstrate the importance of accurate land cover inputs for biogenic emission models and indicate that land cover change should be considered for these models.
Keywords: BVOC emission; Isoprene; Monoterpene; Other VOCs
Emissions of gases and particles from biomass burning during the 20th century using satellite data and an historical reconstruction by A. Mieville; C. Granier; C. Liousse; B. Guillaume; F. Mouillot; J.-F. Lamarque; J.-M. Grégoire; G. Pétron (pp. 1469-1477).
A new dataset of emissions of trace gases and particles resulting from biomass burning has been developed for the historical and the recent period (1900–2005). The purpose of this work is to provide a consistent gridded emissions dataset of atmospheric chemical species from 1900 to 2005 for chemistry-climate simulations. The inventory is built in two steps. First, fire emissions are estimated for the recent period (1997–2005) using satellite products (GBA2000 burnt areas and ATSR fire hotspots); the temporal and spatial distribution of the CO2 emissions for the 1997–2005 period is estimated through a calibration of ATSR fire hotspots. The historical inventory, covering the 1900–2000 period on a decadal basis, is derived from the historical reconstruction of burned areas from . The historical emissions estimates are forced, for each main ecosystem, to agree with the recent inventory estimates, ensuring consistency between past and recent emissions.The methodology used for estimating the fire emissions is discussed, together with the time evolution of biomass burning emissions during the 20th century, first at the global scale and then for specific regions. The results are compared with the distributions provided by other inventories and results of inverse modeling studies.
Keywords: Emissions; Climate change; Gases; Particles; Biomass burning; Burnt areas; Historical; Satellite
Estimated photochemical ozone creation potentials (POCPs) of CF3CFCH2 (HFO-1234yf) and related hydrofluoroolefins (HFOs) by T.J. Wallington; M.P. Sulbaek Andersen; O.J. Nielsen (pp. 1478-1481).
The photochemical ozone creation potentials (POCPs) for CF3CFCH2 and other commercially significant hydrofluoroolefins have been estimated for the first time. CF3CFCH2 (HFO-1234yf) has a POCP of 7.0 which is less than that for ethane (12.3) and greater than for methane (0.6). Methane and ethane have sufficiently low POCPs that they are usually considered unreactive with respect to ozone formation in urban areas and accordingly are exempt from volatile organic compound (VOC) emission regulations. Estimated POCPs for other hydrofluoroolefins are: CH2CF2, 18.0; CF2CF2, 12.5; CH2CHCF3, 10.7; CF2CFCF3, 5.4; Z-CHFCFCF3, 5.6; E-CHFCFCF3, 7.3; CH2CHCF2CF3, 6.6; and t-CHFCHCF3, 6.4.
Keywords: POCP; Hydrofluorocarbons; CFC-replacements; Hydrofluoroolefins; R-1234yf; HFC-1234yf; HFO-1234yf