Emission of non-methane volatile organic compounds (VOCs) from boreal peatland microcosms—effects of ozone exposure

Non-methane volatile organic compounds (VOCs) emitted from boreal peatland microcosms were semiquantitatively determined using gas chromatography–mass spectrometry techniques in a growth chamber experiment. Furthermore, effects of vegetation composition and different ozone concentrations on these emissions were estimated by multivariate data analyses. The study concentrated on the less-studied VOCs, and isoprene was not analyzed. The analyses suggest that a sedge Eriophorum vaginatum is associated with emissions of the four most-emitted VOC groups (cyclic, aromatic, carbonyl and aliphatic hydrocarbon compounds) and also with VOCs emitted in smaller amounts (terpenoids and N-containing compounds). A woody dwarf shrub Andromeda polifolia was strongly associated with emissions of aromatic, carbonyl and terpenoid compounds. Results suggest that exposure to an ozone concentration of 150 ppb leads to an increased emission of most VOC groups. Emission of aromatic compounds seems to increase linearly with increasing ozone concentration. These observations indicate that peatlands may be a source of a vast range of volatile compounds to the atmosphere. For more accurate assessment of the impact of elevated tropospheric ozone on the terpenoid and non-terpenoid VOC emissions from peatlands, well-replicated open-air ozone-exposure experiments should be conducted.     

Estimate of initial isoprene contribution to ozone formation potential in Beijing, China

Volatile organic compounds (VOCs) are important precursors of tropospheric ozone formation. Isoprene contributions to ozone formation by using ambient mixing ratios are generally underestimated because of rapid chemical losses. In this study, ambient mixing ratios of major VOC species were continuously measured at Peking university (PKU) and YUFA, urban and sub-urban sites in Beijing, the city that will host 2008 Olympic Games. The observed mixing ratios of methyl vinyl ketone (MVK), methacrolein (MACR) and isoprene were used to derive the mixing ratios of initial isoprene, which means the ambient isoprene level before it undergoes any photochemical reaction with OH radicals. The average mixing ratios of initial isoprene were 3.3±1.6 and 2.9±1.5 ppbv at PKU and YUFA sites, respectively. The percentages of initial isoprene in total initial VOCs were 10.8% at PKU site and 11.4% at YUFA site, in reasonable agreement with the isoprene contribution in total VOC emissions as derived from source inventories. Maximum increment reactivity (MIR) was used to evaluate the ozone formation potential (OFP) for major VOC species. The OFP for initial isoprene accounted for 23% of the total OFPs for all measured species, compared to 11% using ambient mixing ratios of isoprene at PKU site. Similarly, at YUFA site, the ambient measured isoprene and initial isoprene contributed 10% and 22%, respectively, to the OFPs for total measured VOCs. It seems that isoprene has similar contribution to ozone formation at both sites in Beijing city.     

The contribution of traffic and solvent use to the total NMVOC emission in a German city derived from measurements and CMB modelling

In order to quantify the contribution of solvent use and road traffic to the total non-methane volatile organic compound (NMVOC) emissions in Germany, the composition of air in the city of Wuppertal was investigated during three campaigns at different locations. The measurements covered NMVOCs in the range of C₃–C₁₀ hydrocarbons and C₁–C₆ oxygenated compounds. An assessment of the contribution from different emission sources to the observed NMVOC concentrations was attempted with the chemical mass balance (CMB) modelling technique. Emission profiles for traffic were obtained from measurements performed in a traffic tunnel, at a downtown street intersection and during drives through the city and on motorways. Solvent emission profiles were investigated in the vicinity of different factories and workshops using solvents in Wuppertal. Apportionment analyses were performed for several receptor points located down-wind from the city centre, in residential, dense traffic and industrial areas.The results of the present work show that traffic emission rather than solvent use determines the ambient NMVOC composition. The maximum contribution of solvent use to the NMVOC emission estimated on the basis of experimentally obtained results amounts to about 23% in the whole area of Wuppertal. It can be concluded that the contribution of solvent use to the NMVOC concentrations also in other German cities falls in the range of few to about 20%, assuming that Wuppertal can be considered as a typical German urban area with certain proportions of domestic, traffic and various industrial activities. These results are in strong disagreement with the German Emission Inventory, which states, that in the reference year 2003 about 51% of the total NMVOC emissions originate from solvent use and only 14% from traffic.     

Characterization of ambient volatile organic compounds at a landfill site in Guangzhou,South China

Ambient air monitoring was conducted at Datianshan landfill, Guangzhou, South China in 1998 to investigate the seasonal and horizontal variations of trace volatile organic compounds (VOCs). Twelve sampling points over the Datianshan landfill were selected and samples were collected simultaneously using Carbontrap(TM) adsorption tubes. Thirty eight VOCs were detected in the winter, whereas 60 were detected in the summer. The VOC levels measured in summer were alkanes, 0.5-6.5 microg/m(3); aromatics, 2.3-1667 microg/m(3); chlorinated species, 0.2-31 microg/m(3); terpines, 0.1-34 microg/m(3); carbonyl species, 0.3-5.6 microg/m(3) and naphthalene and its derivatives, 0.4-27 microg/m(3). Compared to the summer samples the VOC levels in winter were much lower (mostly 1-2 orders of magnitude lower). The aromatics are dominant VOCs in landfill air both in winter and summer. High levels of alkylbenzene and terpines such as methyl-isopropylbenzene (max 1667 microg/m(3)) and limonene (max 162 microg/m(3)) cause undesirable odor. The similar correlation coefficients of BTEX in summer and winter suggest VOCs emissions were from landfill site sources. The variation of BTEX ratio at landfill site is different from that in the urban area of Guangzhou. It shows that the ambient VOCs at landfill site were different from the urban areas.     

Greenhouse gas emission potential of the municipal solid waste disposal sites in Thailand

Open dumping and landfilling are the prevalent solid waste disposal practices in Thailand. Surveys on the disposal sites revealed the presence of 95 landfills and 330 open dumps. Methane emission potential at these sites was estimated by three methods. Results of the Intergovernmental Panel on Climate Change (IPCC) method, Landfill Gas Emission model (LandGEM), and closed flux chamber technique were compared. The methane emission potential of 366 Gg/yr using the IPCC method was higher than the estimations of the LandGEM and closed flux chamber method of 115 Gg/yr and 103 Gg/yr, respectively. An understanding of the methane emission potential initiated the analysis of upgrading the open dumps into landfills, adding landfills to meet the future needs and utilization of landfill gases. Upgrading the open dumps to landfills increased the methane emission rates and their utilization potential. Approximately 20 additional landfills may be required to meet future demands. Landfill gas (LFG) utilization appears to be feasible in the large-scale landfills.     

Volatile organic compound emissions from municipal solid waste disposal sites: A case study of Mumbai,India

Improper solid waste management leads to aesthetic and environmental problems. Emission of volatile organic compounds (VOCs) is one of the problems from uncontrolled dumpsite. VOCs are well known to be hazardous to human health and many of them are known or potential carcinogens. They also contribute to ozone formation at ground level and climate change as well. The qualitative and quantitative analysis of VOCs emitting from two municipal waste (MSW) disposal sites in Mumbai, India, namely Deonar and Malad, are presented in this paper. Air at dumpsites was sampled and analyzed on gas chromatography–mass spectrometry (GC-MS) in accordance with U.S. Environmental Protection Agency (EPA) TO-17 compendium method for analysis of toxic compounds. As many as 64 VOCs were qualitatively identified, among which 13 are listed under Hazardous Air Pollutants (HAPs). Study of environmental distribution of a few major VOCs indicates that although air is the principal compartment of residence, they also get considerably partitioned in soil and vegetation. The CO₂ equivalent of target VOCs from the landfills in Malad and Deonar shows that the total yearly emissions are 7.89E+03 and 8.08E+02 kg, respectively. The total per hour ozone production from major VOCs was found to be 5.34E-01 ppb in Deonar and 9.55E-02 ppb in Malad. The total carcinogenic risk for the workers in the dumpsite considering all target HAPs are calculated to be 275 persons in 1 million in Deonar and 139 persons in 1 million in Malad.

Implications: This paper describes the hazards of VOC emission from open dumpsites, a common practice, in an Indian metro city. The subsequent partitioning of the emitted VOCs in other environmental compartment from air is presented. The global warming potential and the health hazards to the dumpsite workers from the emitted VOCs have also been estimated.     

Seasonal patterns of non-terpenoid C6-C10 VOC emission from seven Mediterranean woody species

The seasonal pattern of non-terpenoid C6-C10 VOC emission by seven Mediterranean woody species (Bupleurum fruticosum, Cistus albidus, Pinus halepensis, Arbutus unedo, Erica arborea, Quercus coccifera, and Q. ilex) was studied under field conditions. Branch chamber samples were sorbed on carbotrap and analyzed by thermal desorption in combination with GC-MS. These non-terpenoid C6-C10 VOC emissions were large, almost of similar magnitude to those of terpenes. Overall, maximum values were recorded in spring and summer (up to 12 microg g(-1) DM h(-1) in Q. ilex) and minimum values in autumn and winter (up to 5 microg g(-1) DM h(-1) in Q. ilex). These C6-C10 VOC emissions represented 2.82% of the photosynthetic C fixation in summer and 0.22% in winter. Some compounds such as 2-ethoxyethyl acetate were emitted by most species, others such as 3-hexen-1-ol, phenol or decanal were significantly emitted only by few species. The greatest diversity of emitted non-terpenoid C6-C10 VOCs was observed in spring and in Q. ilex. Temperature seemed a strong driver of these seasonal changes but other species-specific and seasonal factors seem involved. These results indicate that C6-C10 non-terpenoid VOCs contribute a rather significant fraction of the total biogenic VOC flux from these Mediterranean species, especially in spring and summer, and therefore should be considered in VOC emission inventories and in model predictions of tropospheric chemistry.     

Tunnel study of on-road vehicle emissions and the photochemical potential in Taiwan

Motor vehicle emission factors of carbon monoxide (CO) and non-methane volatile organic compounds (NMVOCs) were calculated inside the Chung-Cheng Tunnel of Kaohsiung in Taiwan. The results were compared with those model predictions from the Mobile Taiwan 2.0 model. Individual concentrations of 21 species of NMVOCs were also determined. Photochemical potential of NMVOCs was evaluated by using the maximum incremental reactivity (MIR). Field data showed that the integrated emission factors of CO and NMVOCs for actual fleet were 6.3 and 1.5 g/veh km, respectively. The error range of these factors may be up to 45%. The predicted values by the Mobile Taiwan 2.0 model closely matched the observed data. Concentrations of isopentane, 2-methylpentane, toluene and m,p-xylene were the dominant species of NMVOCs. The ratio of maximum incremental reactivity to NMVOCs concentration was 3.9, similar to those of the studies in the US Fort McHenry and Tuscarora Tunnel.     

A comprehensive study on landfill site selection for Kolkata City,India

Kolkata is one of the four major metropolitan cities in India and the capital city of the state of West Bengal. With an area of 187.33 km² and a population of about 10 million (including a floating population of about 6 million), the city generates about 3500 Metric Ton (MT) of solid waste per day. Currently, Kolkata Municipal Corporation (KMC) disposes its waste at Dhapa (21.47 ha), where the disposal rate exceeds 3000 MT/day, and at Garden Reach (3.52 ha), where the disposal rate is 100 MT/day. Considering the exhaustion of Dhapa land space, city planners are urgently searching for an alternate disposal ground. National Environmental Engineering Research Institute (NEERI), under the sponsorship of Central Pollution Control Board (CPCB), has brought out literature developing the site selection criteria for municipal solid waste disposal ground to suit Indian conditions. The developed criteria encompass environmental conditions, accessibility, geological and hydrogeological conditions, and ecological and societal effects. This paper attempts to locate the most suitable site for disposal of KMC area solid waste using the multicriterion decision analysis as stipulated in CPCB 2003 guidelines and the overlay analysis of geographic information system (GIS).

Implications:The paper is based on landfill site selection for dumping of solid waste generated within Kolkata Municipal Corporation (KMC) area. The methodology uses GIS/remote sensing, Site Sensitivity Index (an offshoot of pairwise comparison technique developed in CPCB 2003 guidelines, Government of India), and the Delphi technique. Dhapa landfill site, where solid waste of KMC area is currently being disposed, is exhausted; the authors of this article thus found it relevant to carry out a research on the selection of an alternative landfill site. The study undertaken was comprehensive, yet presented in a lucid way so that policymakers will find easy to comprehend.     

Measurement of Organic Acids,Aldehydes, and Ketones in Residential Environments and Their Relation to Ozone

Abstract

Ozone and several polar volatile organic compounds (VOCs) including organic acids and carbonyls (aldehydes and ketones) were measured over an approximately 24 hour period in four residences during the winter of 1993 and in nine residences during the summer of 1993. All residences were in the greater Boston, Massachusetts area. The relation of the polar VOCs to the ozone concentration was examined. Indoor carbonyl concentrations were similar between the summer and winter, with the total mean winter concentration being 31.7 ppb and the total mean summer concentration being 36.6 ppb. However, the average air exchange rate was 0.9 hr^?1 during the winter and 2.6 hr^?1 during the summer. Therefore, the estimated carbonyl emission rates were significantly higher during the summer. Indoor organic acid concentrations were about twice as high during the summer as during the winter. For formic acid, the indoor winter mean was 9.8 ppb, and the summer indoor mean was 17.8 ppb. For acetic acid, the indoor winter mean was 15.5 ppb, and the summer indoor mean was 28.7 ppb. The concentrations of the polar VOCs were found to be significantly correlated with one another. Also, the emission rates of the polar VOCs were found to be correlated with both the environmental variables such as temperature and relative humidity and the ozone removal rate; however, it was difficult to apportion the relative effects of the environmental variables and the ozone removal.     

Temperature and air velocity effects on ethanol emission from corn silage with the characteristics of an exposed silo face

Volatile organic compounds (VOCs) from agricultural sources are believed to be an important contributor to tropospheric ozone in some locations. Recent research suggests that silage is a major source of VOCs emitted from agriculture, but only limited data exist on silage emissions. Ethanol is the most abundant VOC emitted from corn silage; therefore, ethanol was used as a representative compound to characterize the pattern of emission over time and to quantify the effect of air velocity and temperature on emission rate. Ethanol emission was measured from corn silage samples removed intact from a bunker silo. Emission rate was monitored over 12 h for a range in air velocity (0.05, 0.5, and 5 m s^?1) and temperature (5, 20, and 35 °C) using a wind tunnel system. Ethanol flux ranged from 0.47 to 210 g m^?2 h^?1 and 12 h cumulative emission ranged from 8.5 to 260 g m^?2. Ethanol flux was highly dependent on exposure time, declining rapidly over the first hour and then continuing to decline more slowly over the duration of the 12 h trials. The 12 h cumulative emission increased by a factor of three with a 30 °C increase in temperature and by a factor of nine with a 100-fold increase in air velocity. Effects of air velocity, temperature, and air-filled porosity were generally consistent with a conceptual model of VOC emission from silage. Exposure duration, temperature, and air velocity should be taken into consideration when measuring emission rates of VOCs from silage, so emission rate data obtained from studies that utilize low air flow methods are not likely representative of field conditions.     

Application of OMI observations to a space-based indicator of NOx and VOC controls on surface ozone formation

We investigated variations in the relative sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NO_x) as inferred from the ratio of the tropospheric columns of formaldehyde to nitrogen dioxide (the “Ratio”) from the Aura Ozone Monitoring Instrument (OMI). Our modeling study suggests that ozone formation decreases with reductions in VOCs at Ratios <1 and NO_x at Ratios >2; both NO_x and VOC reductions may decrease ozone formation for Ratios between 1 and 2. Using this criteria, the OMI data indicate that ozone formation became: 1. more sensitive to NO_x over most of the United States from 2005 to 2007 because of the substantial decrease in NO_x emissions, primarily from stationary sources, and the concomitant decrease in the tropospheric column of NO₂, and 2. more sensitive to NO_x with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. In cities with relatively low isoprene emissions (e.g., Chicago), the data clearly indicate that ozone formation became more sensitive to NO_x from 2005 to 2007. In cities with relatively high isoprene emissions (e.g., Atlanta), we found that the increase in the Ratio due to decreasing NO_x emissions was not obvious as this signal was convolved with variations in the Ratio associated with the temperature dependence of isoprene emissions and, consequently, the formaldehyde concentration.     

Characterization of hydrocarbons, halocarbons and carbonyls in the atmosphere of Hong Kong

Ambient air quality measurements of 156 species including 39 alkanes, 32 alkenes, 2 alkynes, 24 aromatic hydrocarbons, 43 halocarbons and 16 carbonyls, were carried out for 120 air samples collected at two sampling stations (CW and TW) in 2001 throughout Hong Kong. Spatial variations of volatile organic compounds (VOCs) in the atmosphere were investigated. Levels of most alkanes and alkenes at TW site were higher than that at the CW site, while the BTEX concentrations at the two sites were close. The BTEX ratios at CW and TW were 1.6:10.1:1.0:1.6 and 2.1:10.8:1.0:2.0, respectively. For major halogenated hydrocarbons, the mean concentrations of chloromethane, CFCs 12 and 22 did not show spatial variations at the two sites. However, site-specific differences were observed for trichloroethene and tetrachloroethene. Furthermore, there were no significant differences for carbonyls such as formaldehyde, acetaldehyde and acetone between the two sites. The levels of selected hydrocarbons in winter were 1-5 times that in summer. There were no common seasonal trends for carbonyls in Hong Kong. The ambient level of formaldehyde, the most abundant carbonyl, was higher in summer. However, levels of acetaldehyde, acetone and benzaldehyde in winter were 1.6-3.8 times that in summer. The levels of CFCs 11 and 12, and chloromethane in summer were higher than that in winter. Strong correlation of most hydrocarbons with propene and n-butane suggested that the primary contributors of hydrocarbons were vehicular emissions in Hong Kong. In addition, gasoline evaporation, use of solvents, leakage of liquefied petroleum gas (LPG), natural gas leakage and other industrial emissions, and even biogenic emissions affected the ambient levels of hydrocarbons. The sources of halocarbons were mainly materials used in industrial processes and as solvents. Correlation analysis suggested that photochemical reactions made significant contributions to the ambient levels of carbonyls in summer whereas in winter motor vehicle emissions would be the major sources of the carbonyls. The photochemical reactivity of selected VOCs was estimated in this study. The largest contributors to ozone formation were formaldehyde, toluene, propene, m,p-xylene, acetaldehyde, 1-butene/i-butene, isoprene and n-butane, suggesting that motor vehicles, gasoline evaporation, use of solvents, leakage of LPG, photochemical processes and biogenic emission are sources in the production of ozone. On the other hand, VOCs from vehicles and gasoline evaporation were predominant with respect to reactions with OH radical.     

Theory and laboratory study of a tall passive chamber for measuring gas fluxes at soil surface

A tall passive flux chamber with a height significantly greater than its horizontal dimensions is proposed for measuring fluxes of volatile organic compounds (VOCs) at the soil surface. The main feature of this tall chamber is the presence of a vertical concentration gradient of the target gas in the chamber. The emission and transport behavior of the target gas in the soil-chamber system are analyzed using the diffusion theory. A mathematical model is developed to estimate the flux from the soil into the tall chamber, providing the target gas establishes a detectable vertical concentration gradient in the chamber. To obtain the data required for calculating flux, only two gas concentrations (C1 and C2) at two heights (h1 and h2) within the chamber need to be measured at the end of a short chamber placement time (tp). To evaluate the applicability of the tall chamber for measuring flux, several laboratory tests have been conducted, using CH2Cl2 and CH3Br as the target gases. The results indicate that the proposed tall chamber has promising potential as a method for measuring fluxes of VOCs at the soil surface.     

Evaluation of the optimum volatile organic compounds control strategy considering the formation of ozone and secondary organic aerosol in Seoul, Korea

The characteristics of volatile organic compounds (VOCs) and their annual trends in Seoul, Korea were investigated, with their optimal control strategy suggested. The annual concentration of VOCs (96.2–121.1 ppbC) has shown a decreasing trend from 2004 to 2008, suggesting the control strategy via the “Special Measures for Metropolitan Air Quality Improvement,” which was implemented in 2005, has been successful. The contributions of individual VOC to the production of ambient ozone and secondary organic aerosol (SOA) are discussed to assess the adequacy of current control strategies. The contribution of aromatics (C6–C10) to the production of ozone accounted for 38.7–46.3 % of the total ozone production, followed by low carbon alkanes (C2–C6) (27.0–35.9 %). The total SOA formation potential of VOCs was found to range from 2.5 to 3.5 μg m^?3, mainly as a result of aromatics (C6–C10) (over 85 %). Considering the contributions from ozone and SOA production, it was concluded that solvent use was the most important emission source, followed by vehicle exhaust emissions. Thus, the current emission control strategy focused on these two emission sources is appropriate to reduce the VOCs related pollution level of the Seoul Metropolitan Region. Still, an additional control strategy, such as controlling the emissions from meat cooking, which is an emission source of high carbon alkanes (C7–C10), needs to be considered to further reduce the VOCs related pollution level in Seoul.     

Dissolved load of aromatic and halogenated non-methane VOCs in urban sewage during wet and dry seasons

Environmental Science and Pollution Research - Concentration of dissolved aromatic and halogenated non-methane volatile organic compounds (NMVOCs) was estimated in sewage flowing through the open...     

Ozone exposure triggers the emission of herbivore-induced plant volatiles, but does not disturb tritrophic signalling

We evaluated the similarities between ozone-induced and mite-induced emission of volatile organic compounds (VOCs) from lima beans, and tested the response of the natural enemies of herbivores to these emissions using trophic system of two-spotted spider mites and predatory mites. The acute ozone-exposure and spider mite-infestation induced the emission of two homoterpenes, (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, and (Z)-3-hexenyl acetate. Only plants with spider mite-infestation emitted the monoterpene (E)-beta-ocimene. Predatory mites were equally attracted to ozone-exposed and unexposed plants, but discriminated between spider mite-infested and uninfested plants, when both were exposed to ozone. The similarities between ozone and herbivore-induced VOCs suggest that plant defence against phytotoxic ozone and the production of VOCs for attraction of the natural enemies of herbivores may have adaptive coevolution. However, the expected elevated ozone concentrations in future may not disturb tritrophic signalling, unless herbivore-induced VOCs are lost in the process of aerosol formation.     

Design and laboratory testing of a chamber device to measure total flux of volatile organic compounds from the unsaturated zone under natural conditions

To determine if an aquifer contaminated with volatile organic compounds (VOCs) has potential for natural remediation, all natural processes affecting the fate and transport of VOCs in the subsurface must be identified and quantified. This research addresses the quantification of air-phase volatile organic compounds (VOCs) leaving the unsaturated zone soil gas and entering the atmosphere-including the additional flux provided by advective soil-gas movement induced by barometric pumping. A simple and easy-to-use device for measuring VOC flux under natural conditions is presented. The vertical flux chamber (VFC) was designed using numerical simulations and evaluated in the laboratory. Mass-balance numerical simulations based on continuously stirred tank reactor equations (CSTR) provided information on flux measurement performance of several sampling configurations with the final chamber configuration measuring greater than 96% of model-simulated fluxes. A laboratory device was constructed to evaluate the flux chamber under both diffusion-only and advection-plus-diffusion transport conditions. The flux chamber measured an average of 82% of 15 diffusion-only fluxes and an average of 95% of 15 additional advection-plus-diffusion flux experiments. The vertical flux chamber has the capability of providing reliable measurement of VOC flux from the unsaturated zone under both diffusion and advection transport conditions.     

Compilation of a database on the composition of anthropogenic VOC emissions for atmospheric modeling in Europe

To analyse and generate air pollution control strategies and policies, e.g. efficient abatement strategies or action plans that lead to a fulfilment of air quality aims, atmospheric dispersion models (CTMs) have to be used. These models include a chemical model, where the numerous volatile organic compounds (VOCs) species are lumped together in classes. On the other hand, emission inventories usually report only total non-methane VOC (NMVOC), but not a subdivision into these classes. Thus, VOC species profiles are needed that resolve total NMVOC emission data. The objective of this publication is to present the results of a compilation of VOC species profiles that dissolve total VOC into single-species profiles for all relevant anthropogenic emission source categories and the European situation. As in atmospheric dispersion models usually modules for generating biogenic emissions are directly included, only anthropogenic emissions are addressed. VOC species profiles for 87 emission source categories have been developed. The underlying data base can be used to generate the data for all chemical mechanisms. The species profiles have been generated using recent measurements and studies on VOC species resolution and thus represent the current state of knowledge in this area. The results can be used to create input data for atmospheric dispersion models in Europe.The profiles, especially those for solvent use, still show large uncertainties. There is still an enormous need for further measurements to achieve an improved species resolution. In addition, the solvent use directive and the DECOPAINT directive of the European Commission will result in a change of the composition of paints; more water-based and high-solid paints will be used; thus the species resolution will change drastically in the next years. Of course, the species resolution for combustion and production processes also requires further improvement.     

Air Levels and Mutagenicity of PM-10 in an Indoor Ice Arena

Abstract

Hazardous waste sites and industrial facilities contain area sources of fugitive emissions. Emission rate measurements or estimates are necessary for air pathway assessments for these sources. Emission rate data can be useful for the design of emission control and remediation strategies as well as for predictive modeling for population exposure assessments. This paper describes the use of a direct emission measurement approach – the enclosure approach using an emission isolation flux chamber – to measure emission rates of various volatile organic compounds (VOCs) from contaminated soil and water. A variety of flux chamber equipment designs and operating procedures have been employed by various researchers. This paper contains a review of the design and operational variables that affect the accuracy and precision of the method. Guidance is given as to the optimum flux chamber design and operating conditions for various types of emission sources. Also presented is a generic quality control program that gives the minimum number of duplicate, blank, background, and repeat samples that should be performed.