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Atmospheric Environment (v.39, #10)

Editorial board (pp. i).

List for forthcoming papers (pp. i-ii).

Measurements of the kinetics of the OH-initiated oxidation of α-pinene: Radical propagation in the OH+ α-pinene+O₂+NO reaction system by Maxine E. Davis; Philip S. Stevens (pp. 1765-1774).

The mechanism of the OH-initiated oxidation of α-pinene in the presence of NO has been investigated using a discharge-flow system at 5Torr and 300K. The OH concentration was monitored as a function of reaction time by laser-induced fluorescence (LIF). The rate constant for the OH+ α-pinene was measured to be (6.09±0.30)×10⁻¹¹cm³molecule⁻¹s⁻¹. OH radical regeneration was observed after addition of O₂ and NO, and the measured OH concentration profiles were compared to simulations based on both the Master Chemical Mechanism and the Regional Atmospheric Chemistry Mechanism for α-pinene oxidation in order to determine the ability of these mechanisms to describe the observed efficiency of radical propagation. Both models are able to reproduce the observed OH concentrations profiles to within 30%. However, expanding the MCM to include isomerization of the β-hydroxy alkoxy radicals improves the agreement with the experimental observations.

Keywords: α; -pinene; Hydroxyl radical; Tropospheric chemistry; Kinetics; Mechanism

An improvement of the two-stream model for vertical mixing of passive tracer in the convective boundary layer by Jongil Han; Daewon W. Byun (pp. 1775-1788).

The two-stream model (TSM; Chatfield and Brost, J. Geophys. Res. 92 (1987) 13263–13276) was developed to account for advection-like vertical mixing features of a passive tracer in the convective boundary layer (CBL). In the TSM, the tracer is advected by two-streams (that is, mean updraft and downdraft), of which the vertical profiles are prescribed as functions of the CBL similarity scales, that is, the CBL height and velocity scales. Compared to the results from large-eddy simulation (LES) and laboratory model, the TSM shows similar plume propagation behavior, but the plume propagation speed appears to be too slow. This drawback of the TSM is found to be mainly due to too weak updraft and downdraft. To improve the TSM, therefore, we modify the prescribed vertical profiles of the mean updraft and downdraft using the LES data. Compared to the original up and down draft velocity profiles, the modified profiles have significantly larger magnitudes in the lower CBL while having similar magnitudes in the upper CBL. The realism of the modified TSM simulation of vertical mixing in the CBL is tested for near surface and elevated tracer sources against the LES results of which validity has been well verified with laboratory experiments and observation. For comparison purpose, we introduce other non-local closure models such as the Blackadar model, the asymmetric convective model, and the transilient turbulence parameterization as well as a local K-theory-based scheme. The modified TSM not only predicts much more improved tracer propagation than the original TSM but also yields the most superior results among the models introduced in this study, showing a remarkably realistic description of the temporal behavior for the concentration distributions and the ground and source level concentrations.

Keywords: Closure model; Air quality; Vertical transport; Large-eddy simulation

Ambient levels of carbonyl compounds and their sources in Guangzhou, China by Yanli Feng; Sheng Wen; Yingjun Chen; Xinming Wang; Lu Huixiong L�; Xinhui Bi; Guoying Sheng; Jiamo Fu (pp. 1789-1800).

Ambient levels of carbonyl compounds and their possible sources, vehicular exhaust and cooking exhaust, were studied at seven places in Guangzhou, including five districts (a residential area, an industrial area, a botanical garden, a downtown area and a semi-rural area), a bus station and a restaurant during the period of June–September 2003. Nineteen carbonyl compounds were identified in the ambient air, of which acetone was the most abundant carbonyl, followed by formaldehyde and acetaldehyde. Only little changes were found in carbonyl concentration levels in the five different districts because of their dispersion and mixture in the atmosphere in summer. The lower correlations between the carbonyls’ concentrations might result from the mixture of carbonyls derived from different sources, including strong photochemical reactions at noon in summer. Formaldehyde and acetaldehyde were the main carbonyls in bus station, while straight-chain carbonyls were comparatively abundant in cooking exhaust. Besides vehicular exhaust, cooking might be another major source of carbonyl compounds in Guangzhou City, especially for high molecular weight carbonyls.

Keywords: Carbonyl compounds; Vehicular exhaust; Cooking exhaust; Photochemical reactions; Ambient level

Elemental composition of PM₁₀ and PM_2.5 in urban environment in South Brazil by C.F. Braga; E.C. Teixeira; L. Meira; F. Wiegand; M.L. Yoneama; J.F. Dias (pp. 1801-1815).

The purpose of the present study is to analyze the elemental composition and the concentrations of PM₁₀ and PM_2.5 in the Guaíba Hydrographic Basin with HV PM₁₀ and dichotomous samplers. Three sampling sites were selected: 8° Distrito, CEASA and Charqueadas. The sampling was conducted from October 2001 to December 2002. The mass concentrations of the samplers were evaluated, while the elemental concentrations of Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn were determined using the Particle-Induced X-ray Emission (PIXE) technique. Factor Analysis and Canonical Correlation Analysis were applied to the chemical and meteorological variables in order to identify the sources of particulate matter. Industrial activities such as steel plants, coal-fired power plants, hospital waste burning, vehicular emissions and soil were identified as the sources of the particulate matter. Concentration levels higher than the daily and the annual average air quality standards (150 and 50μgm⁻³, respectively) set by the Brazilian legislation were not observed.

Keywords: Particulate matter; PM; ₁₀; PM; _2.5; HV PM; ₁₀; Dichotomous; PIXE; Factor Analysis

Diurnal and seasonal emissions of volatile organic compounds from cork oak ( Quercus suber) trees by C.A. Pio; P.A. Silva; M.A. Cerqueira; T.V. Nunes (pp. 1817-1827).

The emissions of volatile organic compounds from Quercus suber (cork oak) were investigated at two rural sites in Portugal using a branch enclosure method with subsequent analysis by gas chromatography/flame ionization detection. Q. suber leaves released important amounts of monoterpenes, mainly in the form of limonene, α-pinene, β-pinene and sabinene. However, significant temporal and intraspecific variations in the relative abundance of the dominant compounds were found during this survey. Emissions from Q. suber were strongly dependent on light and temperature, showing a similar behaviour to that of plant species known to be isoprene producers. But, this work also revealed that, although at lower rates, emissions of monoterpenes continued in the dark for several hours. Emission rates were quite well predicted by algorithms based on the Guenther and Tingey equations; correlations of measurements with modelled data were, on average,r2=0.80. A pronounced seasonal variation was recorded for the emissions of monoterpenes. During the 1-yr study period, standard emission rates ranged between a minimum of 0.2μgg_dw⁻¹h⁻¹_, in winter, and a maximum of 20–30μgg_dw⁻¹h⁻¹, in summer.

Keywords: Biogenic emissions; Monoterpenes; Seasonal variability; Quercus suber

Atmospheric precipitation and chemical composition of an urban site, Gua�ba hydrographic basin, Brazil by D. Migliavacca; E.C. Teixeira; F. Wiegand; A.C.M. Machado; J. Sanchez (pp. 1829-1844).

The purpose of the present work was to study the chemical composition of bulk and wet atmospheric precipitation in the Guaíba Hydrographic Basin, in South Brazil. The samples were analyzed from January to December 2002 at three different stations, i.e., 8° Distrito and CEASA stations in the city of Porto Alegre, and Charqueadas station, located in the city of same name. The bulk and wet precipitation were analyzed for conductivity, pH, Cl⁻, NO₃⁻, F⁻, SO₄²⁻, Na⁺, K⁺, Mg²⁺, NH₄⁺, Ca²⁺, Cu, Zn, Mn, Fe and Al. The pH values in the samples of atmospheric precipitation ranged between 4.75 and 7.45. The analysis of linear regression applied to the set of studied variables showed that neutralization occurred in samples of bulk and wet precipitation. It was found that the Cl present in samples of atmospheric precipitation originated from sea salts and anthropogenic sources. The principal components analysis (PCA) identified the main anthropogenic sources within the Guaíba Hydrographic Basin (GHB). Cluster analysis grouped the events identified for each station in the PCA in association with the meteorological data.

Keywords: Atmospheric precipitation; Principal components analysis; Chemical elements; Cluster analysis

Measurement of particle phase dry deposition fluxes of polychlorinated biphenyls (PCBs) with a water surface sampler by Y. Y�cel Tasdemir; Thomas M. Holsen (pp. 1845-1854).

It has been shown that the atmospheric pathways including dry deposition are an important source of polychlorinated biphenyls (PCBs) entering surface waters in many locations. To assess how important this pathway is, accurate measurements or modeled estimates of dry deposition are needed. However, dry deposition is not well quantified because the direct measurement of dry deposition is difficult and indirect estimation techniques have substantial uncertainties associated with them. In this study, PCB dry deposition fluxes were directly measured with a water surface sampler (WSS) simultaneously with measurements of airborne concentrations in the Chicago urban area. The average particulate phase PCB flux to the WSS was 240�160ng/m²-d, and the particulate phase airborne concentrations was 0.08�0.05ng/m³. Average overall dry deposition velocities, calculated by dividing the fluxes by total particle phase PCB concentrations were 4.2�2.7cm/s. This number is consistent with values determined using similar experimental techniques and higher than the values typically used to model PCB dry deposition. This difference may be due, in part, to the influence of PCBs associated with large particles being deposited onto the WSS.

Keywords: PCBs; Dry deposition; Deposition velocity; Water surface sampler

Non-methane hydrocarbon emissions from vehicle fuel caps by Stuart A. Batterman; Yungdae Yu; Chunrong Jia; Christopher Godwin (pp. 1855-1867).

Vehicles emit non-methane hydrocarbons (NMHCs) from a number of sources, including missing, worn or improperly tightened fuel caps. Inspection and maintenance programs and the On-Board Diagnostic (OBD) system will detect some of these deficiencies, however, even properly tightened caps will emit NMHCs due to permeation, diffusion, cracks and gaps in seals, and failures of pressure-relief mechanisms. These emissions have not been previously quantified. In this study, in-use emissions from fuel caps were measured in 213 tests on vehicles of varying age and condition over several seasons, including cold and warm temperatures. Diffusion/permeation models are presented to complement the experimental work. NMHC emissions from fuel caps were detected from all vehicles, of which benzene constituted 2.5%. Emissions averaged 2.0mgh⁻¹ (median=0.5mgh⁻¹), and the distribution of emission rates was highly skewed by a small number of vehicles with much higher emissions, e.g., the 90th, 95th and maximum percentile values were 2.7, 5.0, and 62.7mgh⁻¹, respectively. Emission rates increased substantially if the fuel cap was loose, in hot weather, and with vehicle age and mileage. Overall, emissions from properly functioning caps are small relative to running and refueling losses, though they may be significant if the gas cap is defective or loose. Further reductions in emissions may be achieved by using new low-torque cap designs, improved elastomers, properly tightening fuel caps, and replacing old caps.

Keywords: Benzene; Evaporative emissions; Gasoline; Hydrocarbons; Running losses; Volatile organic compounds

Area, mobile, and point source contributions to ground level ozone: a summer simulation across the continental USA by Zhining Tao; Susan M. Larson; Allen Williams; Michael Caughey; Donald J. Wuebbles (pp. 1869-1877).

In this study, we assessed how much ground level O₃ originated from area, mobile, and point sources in the presence of biogenic emissions. We simulated ground level O₃ formation over a three-month period (June–August, 1995) across the continental US, using the procedure for factor separation (FS) to calculate our source contribution. The modeling system includes Sparse Matrix Operator Kernel Emissions (SMOKE), an emissions model, meteorological data from a regional climate model, and SAQM, a 3-D chemistry-transport air quality model. The FS technique is applied to quantify the pure impact from an individual source category as well as the additional impact due to the synergy among source categories. In performing this type of source contribution, it is important to note that the synergy among source categories may sometimes actually suppress O₃ formation in comparison with the sum of pure contribution from the individual source category. In such a case, a negative source contribution is assigned to this interaction. Our simulation results indicate that this suppression does occur and that pure and synergistic contributions vary over time and space. The full potential of each source category in O₃ formation (the pure contribution) is not achieved when emissions from the other source categories are accounted for, implying that control of emissions from one source category could increase the potential of emissions from another source category to produce O₃.

Keywords: Anthropogenic inventory; Factor separation; Photochemical model; Synergy

PM_2.5 mass concentrations in comparison with aerosol optical depths over the Arabian Sea and Indian Ocean during winter monsoon by S. Ramachandran (pp. 1879-1890).

An analysis of PM_2.5 mass concentrations and 0.5μm aerosol optical depths (AODs) during the Northeast winter monsoon seasons of 1996–2000 is performed and intercompared. AODs are found to show diurnal variations over Coastal India (CI) (west coast) while they are relatively smooth over the Arabian Sea (AS) (5–20°N) and tropical Indian Ocean (TIO) (5°N–20°S). PM_2.5, PM₁₀ and total mass concentrations show less variations in a day over these oceanic regions. Columnar AODs are found to increase with an increase in the marine boundary layer aerosol concentrations over CI and AS while an opposite trend is seen over TIO. The yearly-mean AODs and mass concentrations are found to increase over CI and AS, over TIO the mass concentrations increased while the AODs decreased during 1996–2000. It is found from the 7-days air back trajectory analyses that at different altitudes air masses can originate from different source regions leading to changes in chemical, physical and optical characteristics of the aerosol between the surface and column. The differences in the surface and columnar measurements could also occur due to changes in the meteorological conditions, wind patterns, in addition to changes in production and subsequently the transport of aerosols. Least-squares fits to the above intercomparison resulted in intercepts of 0.24 and 0.22 over CI and AS indicating that the background AODs over these oceanic regions are higher. An examination of the daily-mean wind speeds and PM_2.5 mass concentrations yielded an index of wind dependence of 0.04 for AS and 0.07 for TIO. The background PM_2.5 mass concentrations are also found to be high at 36 and 25μgm⁻³ over AS and TIO, respectively, indicating a stronger influence from the continent.Frequency distribution figures show that 28% of the PM_2.5 values over CI lie in the 60–80μgm⁻³ range. Over AS the dominant mode of distribution is 40–60μgm⁻³ with a peak value of 42%. Over TIO PM_2.5 values are found to peak in the lower mass bin of 0–20μgm⁻³ at 33%. A latitudinal gradient is seen in the peak bin value of PM_2.5 as the ship moves away from the coast. About half the days over CI and 20% over AS and TIO, PM_2.5 values are found unhealthy indicating the influence of anthropogenic pollution and long-range transport of pollutants from the surrounding continental locations across these oceanic regimes. AODs are found to peak in the 0.2–0.4 bin at 52% over CI and 47% over AS. Over AS 32% of the AODs are found to be <0.2. More than 90% of AODs over TIO are <0.2. The feature is different when compared to three maritime locations in the Pacific where 75% or more cases have AODs <0.1.α values are found to peak in the 1.5–2 range over CI at 55% while they peak in the lower range of 1–1.5 at 49% and 26% over AS and TIO, respectively. Over the Pacific and Atlantic Oceans in more than 90% of the casesα was ⩽1.5, indicating that the amount of smaller and larger particles are higher over the Indian Ocean when compared to the Pacific and Atlantic. The spread in PM_2.5 and AOD indicates that it is a challenging task to obtain a good relation without additional inputs on the vertical distribution of aerosols as varied kinds of aerosols from different source regions contribute at different heights over these oceanic regions.

Keywords: Aerosol mass concentrations; Optical depths; �ngstr�m wavelength exponents; Frequency distributions; Arabian sea; Indian Ocean

Effectiveness of street sweeping and washing for controlling ambient TSP by Y.-M. Yu-Min Chang; C.-M. Chih-Mei Chou; K.-T. Kuo-Tung Su; C.-H. Chao-Heng Tseng (pp. 1891-1902).

Effectiveness of street sweeping and washing (S/W) for controlling ambient “total suspended particles (TSP)�? was evaluated by TSP measurements and determining silt load from active traffic streets. A modified regenerative-air vacuum sweeper (RAVS) and a washer were used in this study. The sweeper made a pass followed by the washer. The S/W efficiencies(ηs,ηT) were obtained based on the experimental data of silt loading and TSP. It was found that the direct impact of sweeping on ambient TSP emissions was short-lived lasting no more than 3–4h. When a vacuum sweeper and a washer, respectively, did a good job collecting or cleaning the visible fine particles on roads, the method of S/W tested in this work was effective at removing the sources of the road dust particles. This paper concludes that street sweeping followed by washing was found to offer a measurable reduction in TSP emission potentials. Typically, the reduction efficiency of ambient TSP is up to 30%. Finally, correlated withηS (based on silt loading), a useful equation is proposed to estimate the S/W efficiency,ηT (based on TSP) with a standard error of ±20%. It seems feasible to predict the reduction efficiency of ambient TSP controlled by the regenerative-air vacuum sweeper and washer used in this work for engineering applications. Effects of traffic volume and wind velocity on the S/W efficiencies are also discussed in the paper.

Keywords: Street sweeping; Sweeping efficiency; Fugitive dust; TSP

Environmental burden of acid gas emissions associated with the exceedence of critical loads by Bernard E.A. Fisher (pp. 1903-1915).

This paper demonstrates an approach to assessing environmental burdens based on optimising the integrated deposition footprints of characteristic sources, such as power stations, urban areas or poultry farms, relative to 1km�1km ecosystem-dependent critical loads. It makes use of a penalty function and an adjoint Green's function method describing how the deposition of acid gases and reduced nitrogen compounds compare with critical loads, from which the optimum source location in Great Britain may be found. The effect of a unit of emission from a source category can be described on a single map. This simple risk based approach to environmental burdens is compared to a more elaborate optimisation, using large combustion plant emissions as an example.

Keywords: Environmental burden; Acid deposition; Penalty function; Large combustion plant; Adjoint Green's function; Optimisation; Acid gas; Reduced nitrogen

On the universality of the dissipation rate functional form and of the autocorrelation function exponential form by G.A. Gerv�sio A. Degrazia; O.C. Ot�vio C. Acevedo; Jonas C. Carvalho; A.G. Ant�nio G. Goulart; Osvaldo L.L. Moraes; Haroldo F. Campos Velho; Davidson M. Moreira (pp. 1917-1924).

An alternative formulation for the turbulence dissipation rateε is presented. The development consists on a binomial expansion of an algebraic relation for the lateral dispersion parameter σ _y, originated from the fitting of experimental data. The new formulation keeps the same physical premises contained on the classical, largely used one, but the numerical coefficient increases by a factor of 50%. The new expression leads to dissipation rate values, which are shown to be in good agreement with those previously determined in the convective boundary layer. Furthermore, a statistical comparison to observed concentration data shows that the alternative relation for the dissipation rate is suitable for application in Lagrangian stochastic dispersion models. Motivated by these results, a new form for the autocorrelation function has also been obtained. Once the procedures that originated both the new and classical formulations are similar, only starting from a different expression for σ _y, this study shows that there is no universal certainty regarding the dissipation rate functional form and the autocorrelation function exponential form.

Keywords: Turbulence dissipation rate; Autocorrelation function; Dispersion parameters

Major chemical components of PM2.5 in Milan (Italy) by Giovanni Lonati; Michele Giugliano; Paola Butelli; Laura Romele; Ruggero Tardivo (pp. 1925-1934).

PM2.5 speciation for the major chemical components has been performed on 109 daily samples collected by a high-volume gravimetric automatic sequential sampler. The 24-h sampling campaigns have been performed at an urban background (UB) site and at a tunnel site in the city of Milan. PM2.5-loaded filters are analysed for the main ionic components (chloride, nitrate, sulphate, ammonium) and the carbon species, elemental carbon (EC) and organic carbon (OC). The species analysed identify on average about 90% of the total mass sampled in the UB site and about 80% of the total mass sampled in the tunnel site. For the latter site a more complete characterisation, accounting for elemental composition, is performed: mass closure that also includes crustal fraction and metal oxides results in a slight overestimation (5%) of the total PM2.5 mass. Based on elemental composition data, the role of the potential sources of crustal and anthropogenic components is identified by the enrichment factor technique. The values obtained for the speciation are typical of urban areas and point out a strong contribution of the secondary source and a small contribution from the emissions of stationary sources in winter. A 0.9 value for the ratio between organic compounds and elemental carbon in PM2.5 samples collected at the tunnel site is observed. Applying the OC/EC ratio approach, this value, representative of the real traffic emissions for the circulating vehicle fleet in Milan, is used for the determination of primary organic aerosols due to traffic in ambient PM2.5. The primary contribution of the traffic source, in terms of carbonaceous matter (EC and primary organic aerosols), is estimated in 6% and 11% of the total PM2.5 mass, respectively, in the cold and warm season. The same OC/EC ratio approach also allows for the evaluation of secondary organic aerosols (SOA) presence in warm season PM2.5 samples: SOA is about 85% of total particulate organic matter and 30% of the total PM2.5 mass. Results obtained for the primary contribution of traffic and for SOA contribution to PM2.5 concentration levels confirm that traffic restriction interventions are not effective to provide relevant short-term air quality improvement. The need to control the emission of the precursors of PM2.5 secondary components is pointed out.

Keywords: Fine particulate matter; Chemical speciation; Carbon species; Real traffic; OC/EC ratio; Secondary organic aerosol

Study of reaction processes of furan and some furan derivatives initiated by Cl atoms by Caba�as B. Caba�as; F. Villanueva; Mart�n P. Mart�n; M.T. Baeza; S. Salgado; Jim�nez E. Jim�nez (pp. 1935-1944).

The reactions of chlorine (Cl) atoms with volatile organic compounds (VOCs) emitted into the atmosphere are of interest to understand the role of Cl in the marine and coastal chemistry. The rate coefficients for Cl-atom reactions with organic compounds are typically about one or two order of magnitude larger than the ones corresponding to OH reaction. We report here the first kinetic measurements of the reactions of atomic Cl with some VOCs: furan, 2-methylfuran, 3-methylfuran, 2-ethylfuran, and 2,5-dimethylfuran.The reactions of atomic Cl with furan and its derivatives were studied at 298±2K and 1atm pressure using a relative rate technique with GC-FID/MS detection of the organic compounds. Thionyl chloride and trichloroacetyl chloride were used as Cl-atom precursors since molecular Cl reacted in the dark with the studied compounds.The ratios of rate coefficients for Cl-atom reactions with furan and its derivatives relative to n-nonane were as follows: furan (0.41±0.05); 2-methylfuran (0.85±0.03); 3-methylfuran (0.88±0.04); 2-ethylfuran (0.95±0.05); and 2,5-dimethylfuran (1.17±0.06). Taking k(Cl+ n-nonane)=(4.82±0.14)×10⁻¹⁰cm³molecule⁻¹s⁻¹ the absolute rate coefficients obtained (in units of 10⁻¹⁰cm³molecule⁻¹s⁻¹) were: furan (2.0±0.2); 2-methylfuran (4.1±0.2); 3-methylfuran (4.2±0.3); 2-ethylfuran (4.6±0.3); and 2,5-dimethylfuran (5.7±0.3). All errors are ±2 σ.The influence of the structure on the reactivity of these compounds and the atmospheric implications are discussed.

Keywords: Furan; Chlorine-atoms; Rate coefficient; Relative method; Tropospheric chemistry

Diurnal changes in the distribution of dicarboxylic acids, ketocarboxylic acids and dicarbonyls in the urban Tokyo atmosphere by Kimitaka Kawamura; Osamu Yasui (pp. 1945-1960).

Secondary organic aerosol in the urban atmosphere is an important issue of not only local air pollution but also regional and global atmospheric chemistry. To better understand the production of water-soluble organic aerosols, we analyzed time-series aerosol samples collected in Tokyo every 3h during summer and winter campaigns for homologous dicarboxylic acids (C₂–C₁₀), ketocarboxylic acids (C₂–C₄) and α-dicarbonyls (C₂–C₃) using a GC and GC/MS. Here, we report, for the first time, diurnal distributions of dicarboxylic acids, ketoacids and dicarbonys in the urban atmosphere. Oxalic acid was found as the most abundant species, followed by malonic, succinic, phthalic, pyruvic and glyoxylic acids. Total concentrations of diacids, ketoacids and dicarbonyls showed a concentration maximum in daytime (11–14h) with a dynamic change in their molecular composition especially in summer samples. Relative abundances of unsaturated (maleic, methylmaleic and phthalic) and some saturated (methylsuccinic and adipic) species increased in the morning (8–11h) whereas those of oxalic acid decreased down to 35% in 8–11h but increased up to 58% toward 17–20h. The diurnal variations are interpreted by photochemical production of diacids, where unsaturated and some saturated species are preferentially generated early in the morning via photo-oxidation of aromatic hydrocarbons and cyclic olefins and further oxidized to oxalic acid in the afternoon.

Keywords: Dicarboxylic acid; Ketocarboxylic acids; Dicarbonyls; Urban aerosols; Photochemical production of organic aerosols

Distributed run of a one-dimensional model in a regional application using SOAP-based web services by Gerhard Smiatek (pp. 1961-1966).

This article describes the setup of a distributed computing system in Perl. It facilitates the parallel run of a one-dimensional environmental model on a number of simple network PC hosts. The system uses Simple Object Access Protocol (SOAP) driven web services offering the model run on remote hosts and a multi-thread environment distributing the work and accessing the web services. Its application is demonstrated in a regional run of a process-oriented biogenic emission model for the area of Germany. Within a network consisting of up to seven web services implemented on Linux and MS-Windows hosts, a performance increase of approximately 400% has been reached compared to a model run on the fastest single host.

Keywords: Distributed computing; Web services; SOAP; Perl; BVOC

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Atmospheric Environment (v.39, #10)