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.     

Evaluation of a Test Method for Measuring Indoor Air Emissions from Dry-Process Photocopiers

ABSTRACT

A large chamber test method for measuring indoor air emissions from office equipment was developed, evaluated, and revised based on the initial testing of four dry-process photocopiers. Because all chambers may not necessarily produce similar results (e.g., due to differences in sink effects, temperature and humidity control, air exchange, pollutant monitoring, and measurement biases), a preliminary four-laboratory evaluation of the revised test method was conducted. To minimize variability, the evaluation used a single dry-process photocopier that was shipped to each of the four laboratories along with supplies (i.e., toner and paper).

The results of this preliminary four-laboratory evaluation demonstrate that the test method was used successfully in the different chambers to measure emissions from dry-process photocopiers. Differences in chamber design and construction appeared to have had minimal effect on the results for the volatile organic compounds (VOCs). Perhaps more important than the chamber itself is the sample analysis as identified by duplicate samples that were analyzed by a different laboratory. Percent relative standard deviation (%RSD) was used to provide a simplistic view of interlaboratory precision for this evaluation. Excluding problems with suspected analytical bias observed from one of the laboratories, the precision was excellent for the VOCs with RSDs of less than 10% in most cases. Less precision was observed among the laboratories for aldehydes/ketones (RSD of 23.2% for formaldehyde). The precision for ozone emission rates among three of the laboratories was excellent (RSD of 7.9%), but emission rates measured at the fourth laboratory were much higher.     

Evaluation of total volatile organic compound emissions from adhesives based on chamber tests

In 1997, Homeswest in western Australia and Murdoch University developed a project to construct low-allergen houses (LAHs) in a newly developed suburb. Before the construction of LAHs, all potential volatile organic compound (VOC) emission materials used in LAHs are required to be measured to ensure that they are low total VOC (TVOC) emission materials. This program was developed based on this purpose. In recent times, the number of complaints about indoor air pollution caused by VOCs has increased. A number of surveys of indoor VOCs have indicated that many indoor materials contribute to indoor air pollution. Although some studies have been conducted on the characteristics of VOC emissions from adhesives, most of them were focused on VOC emissions from floor adhesives. Few measurements of VOC emissions from adhesives used for wood, fabrics, and leather are available. Furthermore, most research on VOC emissions from adhesives has been done in countries with cool climates, where ventilation rates in the indoor environment are lower than those in Mediterranean climates, due to energy conservation. VOCs emitted from adhesives have not been sufficiently researched to prepare an emission inventory to predict indoor air quality and to determine both exposure levels for the Australian population and the most appropriate strategies to reduce exposure. An environmental test chamber with controlled temperature, relative humidity, and airflow rate was used to evaluate emissions of TVOCs from three adhesives used frequently in Australia. The quantity of TVOC emissions was measured by a gas chromatography/flame ionization detector. The primary VOCs emitted from each adhesive were detected by gas chromatography/mass spectrometry. The temporal change of TVOC concentrations emitted from each adhesive was tested. A double-exponential equation was then developed to evaluate the characteristics of TVOC emissions from these three adhesives. With this double-exponential model, the physical processes of TVOC emissions can be explained, and a variety of emission parameters can be calculated. These emission parameters could be used to estimate real indoor TVOC concentrations in Mediterranean climates.     

Sampling and Analysis of Volatile Organic Compounds Evolved During Thermal Processing of Acrylonitrile Butadiene Styrene Composite Resins

Abstract

The evaluation of emissions of volatile organic compounds (VOCs) during processing of resins is of interest to resin manufacturers and resin processors. An accurate estimate of the VOCs emitted from resin processing has been difficult due to the wide variation in processing facilities. This study was designed to estimate the emissions in terms of mass of emitted VOC per mass of resin processed.

A collection and analysis method was developed and validated for the determination of VOCs present in the emissions of thermally processed acrylonitrile butadiene styrene (ABS) resins. Four composite resins were blended from automotive, general molding, pipe, and refrigeration grade ABS resins obtained from the manufacturers. Emission samples were collected in evacuated 6-L Summa canisters and then analyzed using gas chromatography/flame ionization detection/mass selective detection (GC/FID/MSD). Levels were determined for nine target analytes detected in canister samples, and for total VOCs detected by an inline GC/FID. The emissions evolved from the extrusion of each composite resin were expressed in terms of mass of VOCs per mass of processed resin. Styrene was the principal volatile emission from all the composite resins. VOCs analyzed from the pipe resin sample contained the highest level of styrene at 402 μg/g. An additional collection and detection method was used to determine the presence of aerosols in the emissions. This method involved collecting particulates on glass fiber filters, extracting them with solvents, and analyzing them using gas chromatography/mass spectrometry (GC/MS). No significant levels of any of the target analytes were detected on the filters.     

Destruction of Volatile Organic Compounds Using Catalytic Oxidation

Catalytic oxidation is an air pollution control technique in which volatile organic compounds (VOCs) and vapor-phase air toxics in an air emission stream are oxidized with the help of a catalyst Design of catalytic systems for control of point source emissions is based on stream-specific characteristics and desired control efficiency. This paper discusses the key emission stream characteristics and VOC characteristics that affect the applicability of catalytic oxidation. The application of catalytic oxidation technology to four types of air emission sources is discussed: (1) groundwater stripping operations; (2) graphic arts facilities; (3) flexographic printing plants; and (4) latex monomer production. The characteristics of each of these emissions are discussed along with the catalytic technology used to control these emissions.     

Direct measurement of fugitive emissions of hydrocarbons from a refinery

Refineries are a source of emissions of volatile hydrocarbons that contribute to the formation of smog and ozone. Fugitive emissions of hydrocarbons are difficult to measure and quantify. Currently these emissions are estimated based on standard emission factors for the type and use of equipment installed. Differential absorption light detection and ranging (DIAL) can remotely measure concentration profiles of hydrocarbons in the atmosphere up to several hundred meters from the instrument. When combined with wind speed and direction, downwind vertical DIAL scans can be used to calculate mass fluxes of the measured gas leaving the site. Using a mobile DIAL unit, a survey was completed at a Canadian refinery to quantify fugitive emissions of methane, C2+ hydrocarbons, and benzene and to apportion the hydrocarbon emissions to the various areas of the refinery. Refinery fugitive emissions as measured with DIAL during this demonstration study were 1240 kg/hr of C2+ hydrocarbons, 300 kg/hr of methane, and 5 kg/hr of benzene. Storage tanks accounted for over 50% of the total emissions of C2+ hydrocarbons and benzene. The coker area and cooling towers were also significant sources. The C2+ hydrocarbons emissions measured during the demonstration amounted to 0.17% of the mass of the refinery hydrocarbon throughput for that period. If the same loss were repeated throughout the year, the lost product would represent a value of US$3.1 million/yr (assuming US$40/bbl). The DIAL-measured hourly emissions of C2+ hydrocarbons were 15 times higher than the emission factor estimates and gave a different perspective on which areas of the refinery were the main source of emissions. Methods, such as DIAL, that can directly measure fugitive emissions would improve the effectiveness of efforts to reduce emissions, quantify the reduction in emissions, and improve the accuracy of emissions data that are reported to regulators and the public.     

An inverse approach for estimating the initial distribution of volatile organic compounds in dry building material

A model for the prediction of emission of volatile organic compounds (VOCs) from dry building material was developed based on mass transfer theory. The model considers both diffusion and convective mass transfer. In addition, it does not neglect the fact that, in most cases, the initial distribution of VOCs within the material is non-uniform. Under the condition that the initial amount of VOCs contained in the building material is the same, six different types of initial VOC distributions were studied in order to show their effects on the characteristics of emission. The results show that, for short-term predictions, the effects are significant and thus cannot be neglected. Based on the fact that the initial distribution of VOCs is very difficult to directly determine, a conjugate gradient method with an adjoint problem for estimating functions was developed, which can be used to inversely estimate the initial distribution of VOCs within the material without a priori information on the functional form of the unknown function. Simulated measurements with and without measurement errors were used to validate the algorithm. This powerful method successfully recovered all of the aforementioned six different types of initial VOC distributions. A deviation between the exact and predicted initial condition near the bottom of the material was noticed, and a twin chamber method is proposed to obtain more accurate results. With accurate knowledge of the initial distribution of VOCs, source models will be able to yield more accurate predictions.     

Emission characteristics of volatile organic compounds from semiconductor manufacturing

A huge amount of volatile organic compounds (VOCs) is produced and emitted with waste gases from semiconductor manufacturing processes, such as cleaning, etching, and developing. VOC emissions from semiconductor factories located at Science-Based Industrial Park, Hsin-chu, Taiwan, were measured and characterized in this study. A total of nine typical semiconductor fabricators (fabs) were monitored over a 12-month period (October 2000-September 2001). A flame ionization analyzer was employed to measure the VOC emission rate continuously in a real-time fashion. The amount of chemical use was adopted from the data that were reported to the Environmental Protection Bureau in Hsin-chu County as per the regulation of the Taiwan Environmental Protection Administration. The VOC emission factor, defined as the emission rate (kg/month) divided by the amount of chemical use (L/month), was determined to be 0.038 +/- 0.016 kg/L. A linear regression equation is proposed to fit the data with the correlation coefficient (R2)=0.863. The emission profiles of VOCs, which were drawn using the gas chromatograph/mass spectrometer analysis method, show that isopropyl alcohol is the dominant compound in most of the fabs.     

Predicting emissions from oil and gas operations in the Uinta Basin,Utah

In this study, emissions of ozone precursors from oil and gas operations in Utah’s Uinta Basin are predicted (with uncertainty estimates) from 2015–2019 using a Monte-Carlo model of (a) drilling and production activity, and (b) emission factors. Cross-validation tests against actual drilling and production data from 2010–2014 show that the model can accurately predict both types of activities, returning median results that are within 5% of actual values for drilling, 0.1% for oil production, and 4% for gas production. A variety of one-time (drilling) and ongoing (oil and gas production) emission factors for greenhouse gases, methane, and volatile organic compounds (VOCs) are applied to the predicted oil and gas operations. Based on the range of emission factor values reported in the literature, emissions from well completions are the most significant source of emissions, followed by gas transmission and production. We estimate that the annual average VOC emissions rate for the oil and gas industry over the 2010–2015 time period was 44.2E+06 (mean) ± 12.8E+06 (standard deviation) kg VOCs per year (with all applicable emissions reductions). On the same basis, over the 2015–2019 period annual average VOC emissions from oil and gas operations are expected to drop 45% to 24.2E+06 ± 3.43E+06 kg VOCs per year, due to decreases in drilling activity and tighter emission standards.

Implications: This study improves upon previous methods for estimating emissions of ozone precursors from oil and gas operations in Utah’s Uinta Basin by tracking one-time and ongoing emission events on a well-by-well basis. The proposed method has proven highly accurate at predicting drilling and production activity and includes uncertainty estimates to describe the range of potential emissions inventory outcomes. If similar input data are available in other oil and gas producing regions, then the method developed here could be applied to those regions as well.     

Assessment of volatile organic compound and hazardous air pollutant emissions from oil and natural gas well pads using mobile remote and on-site direct measurements

Emissions of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) from oil and natural gas production were investigated using direct measurements of component-level emissions on pads in the Denver-Julesburg (DJ) Basin and remote measurements of production pad-level emissions in the Barnett, DJ, and Pinedale basins. Results from the 2011 DJ on-site study indicate that emissions from condensate storage tanks are highly variable and can be an important source of VOCs and HAPs, even when control measures are present. Comparison of the measured condensate tank emissions with potentially emitted concentrations modeled using E&P TANKS (American Petroleum Institute [API] Publication 4697) suggested that some of the tanks were likely effectively controlled (emissions less than 95% of potential), whereas others were not. Results also indicate that the use of a commercial high-volume sampler (HVS) without corresponding canister measurements may result in severe underestimates of emissions from condensate tanks. Instantaneous VOC and HAP emissions measured on-site on controlled systems in the DJ Basin were significantly higher than VOC and HAP emission results from the study conducted by Eastern Research Group (ERG) for the City of Fort Worth (2011) using the same method in the Barnett on pads with low or no condensate production. The measured VOC emissions were either lower or not significantly different from the results of studies of uncontrolled emissions from condensate tanks measured by routing all emissions through a single port monitored by a flow measurement device for 24 hr. VOC and HAP concentrations measured remotely using the U.S. Environmental Protection Agency (EPA) Other Test Method (OTM) 33A in the DJ Basin were not significantly different from the on-site measurements, although significant differences between basins were observed.

Implications: VOC and HAP emissions from upstream production operations are important due to their potential impact on regional ozone levels and proximate populations. This study provides information on the sources and variability of VOC and HAP emissions from production pads as well as a comparison between different measurement techniques and laboratory analysis protocols. On-site and remote measurements of VOC and HAP emissions from oil and gas production pads indicate that measurable emissions can occur despite the presence of control measures, often as a result of leaking thief hatch seals on condensate tanks. Furthermore, results from the remote measurement method OTM 33A indicate that it can be used effectively as an inspection technique for identifying oil and gas well pads with large fugitive emissions.     

Canister-Based Method for Monitoring Toxic VOCs in Ambient Air

The availability of reliable, accurate and precise monitoring methods for toxic volatile organic compounds (VOCs) is a primary need for state and local agencies addressing daily monitoring requirements related to odor complaints, fugitive emissions, and trend monitoring. The canister-based monitoring method for VOCs is a viable and widely used approach that is based on research and evaluation performed over the past several years. This activity has involved the testing of sample stability of VOCs in canisters and the design of time-integrative samplers. The development of procedures for analysis of samples in canisters, including the procedure for VOC preconcentration from whole air, the treatment of water vapor in the sample, and the selection of an appropriate analytical finish has been accomplished. The canister-based method was initially summarized in the EPA Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air as Method TO-14. Modifications and refinements are being added to Method TO-14 in order to obtain a Statement of Work for the Superfund Contract Laboratory Program for Air. This paper discusses the developments leading to the current status of the canisterbased method and provides a critique of the method using results obtained in EPA monitoring networks.     

Development of emission factors for polycarbonate processing

Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 degrees C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.     

Estimation of the rate of VOC emissions from solvent-based indoor coating materials based on product formulation

Two computational methods are proposed for estimation of the emission rate of volatile organic compounds (VOCs) from solvent-based indoor coating materials based on the knowledge of product formulation. The first method utilizes two previously developed mass transfer models with two key parameters – the total vapor pressure and the average molecular weight for total volatile organic compounds (TVOCs) – being estimated based on the VOC contents in the product. The second method is based on a simple, first-order decay model with its parameters being estimated from the properties of both the source and the environment. All the model parameters can be readily obtained. Detailed procedures for computing the key parameters are described by using examples. The predictive errors were evaluated with small chamber data, and the results were satisfactory. Thus, the proposed methods provide a way to predict the VOC emissions in the indoor environment without having to conduct costly chamber testing. The two proposed methods work for both TVOCs and individual VOCs. Pros and cons for each method are discussed.     

The emission patterns of volatile organic compounds during aerobic biotreatment of municipal solid waste using continuous and intermittent aeration

Because volatile organic compounds (VOCs) are one of the main concerns during municipal solid waste (MSW) treatment, the release patterns and the environmental effects of VOCs were investigated during laboratory-scale aerobic biotreatments of MSW with continuous and intermittent negative ventilation. When the same airflow amounts were used, intermittent ventilation was found to reduce the total VOC emissions from continuous ventilation process by 28%. In this study, 23 types of volatile organic compounds were analyzed, of which butyraldehyde, ethanol, and butanone were emitted in the highest concentrations of 748, 372, and 260 mg/m3, respectively. During the aerobic biotreatment process, ketones, aldehydes, and alcohols were primarily released during the first 4 days, accounting for 86-98% of the total VOC emissions during this period. The emission concentrations of malodorous sulfide compounds displayed two peaks on day 4 and day 9, with the contribution to the total VOC emissions being enhanced from less than 10% to 76-83%. The release of terpenes and aromatics lasted for more than 10 days with no significant emission peaks and the proportions of those compounds in the total VOCs increased gradually, but no more than 50% even at the end of the process. Considering the strength of the odors, aldehydes were the predominant contributors at the beginning of the experiment, whereas malodorous sulfide compounds became the most odorous compound as the biological process continued. Most of the VOCs emitted at the concentrations beneath the level causing health threat to the workers.     

Emission Characteristics of Volatile Organic Compounds from Semiconductor Manufacturing

Abstract

A huge amount of volatile organic compounds (VOCs) is produced and emitted with waste gases from semiconductor manufacturing processes, such as cleaning, etching, and developing. VOC emissions from semiconductor factories located at Science-Based Industrial Park, Hsin-chu, Taiwan, were measured and characterized in this study. A total of nine typical semiconductor fabricators (fabs) were monitored over a 12-month period (October 2000-September 2001). A flame ionization analyzer was employed to measure the VOC emission rate continuously in a real-time fashion. The amount of chemical use was adopted from the data that were reported to the Environmental Protection Bureau in Hsin-chu County as per the regulation of the Taiwan Environmental Protection Administration. The VOC emission factor, defined as the emission rate (kg/month) divided by the amount of chemical use (L/month), was determined to be 0.038 ± 0.016 kg/L. A linear regression equation is proposed to fit the data with the correlation coefficient (R²) = 0.863. The emission profiles of VOCs, which were drawn using the gas chromatograph/mass spectrometer analysis method, show that isopropyl alcohol is the dominant compound in most of the fabs.     

Development of Emission Factors for Polycarbonate Processing

Abstract

Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 °C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.     

Aerostat-lofted instrument and sampling method for determination of emissions from open area sources

An aerostat-borne instrument and sampling method was developed to characterize air samples from area sources, such as emissions from open burning. The 10 kg battery-powered instrument system, termed “the Flyer”, is lofted with a helium-filled aerostat of 4 m nominal diameter and maneuvered by means of one or two tethers. The Flyer can be configured variously for continuous CO₂ monitoring, batch sampling of semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs), black carbon, metals, and PM by size. The samplers are controlled by a trigger circuit to avoid unnecessary dilution from background sampling when not within the source plume. The aerostat/Flyer method was demonstrated by sampling emissions from open burning (OB) and open detonation (OD) of military ordnance. A carbon balance approach was used to derive emission factors that showed excellent agreement with published values.     

机动车尾气VOCs排放特征及减排措施研究

分析了机动车尾气挥发性有机物(VOCs)的排放特征,发现尾气VOCs排放具有明显的日变化和季节变化特征。不同区域不同车型机动车尾气VOCs成分谱略有差异,轻型汽油车尾气VOCs中芳香烃和烷烃含量较高,柴油车烷烃含量较高。尾气排放受机动车保有量、行驶里程、维护保养水平、行驶速度和燃油标准、排放标准等因素影响。从优先控制汽油车、加快机动车更新、采取本地化减排措施、加强多元管理措施、提高科研水平等方面提出了针对性的减排措施。     

Emission,speciation, and evaluation of impacts of non-methane volatile organic compounds from open dump site

Surface emission from Dhapa, the only garbage disposal ground in Kolkata, is a matter of concern to the local environment and also fuels the issues of occupational and environmental health. Surface emission of the Dhapa landfill site was studied using a flux chamber measurement for nonmethane volatile organic compounds (NMVOCs). Eighteen noncarbonyl volatile organic compounds (VOCs) and 14 carbonyl VOCs, including suspected and known carcinogens, were found in appreciable concentrations. The concentrations of the target species in the flux chamber were found to be significantly higher for most of the species in summer than winter. Surface emission rate of landfill gas was estimated by using two different approaches to assess the applicability for an open landfill site. It was found that the emissions predicted using the model Land GEM version 3.02 is one to two orders less than the emission rate calculated from flux chamber measurement for the target species. Tropospheric ozone formation has a serious impact for NMVOC emission. The total ozone-forming potential (OFP) of the Dhapa dumping ground considering all target NMVOCs was estimated to be 4.9E+04 and 1.2E+05 g/day in winter and summer, respectively. Also, it was found that carbonyl VOCs play a more important role than noncarbonyl VOCs for tropospheric ozone formation. Cumulative cancer risk estimated for all the carcinogenic species was found to be 2792 for 1 million population, while the total noncancer hazard index (HI) was estimated to be 246 for the occupational exposure to different compounds from surface emission to the dump-site workers at Dhapa.

Implications:This paper describes the real-time surface emission of NMVOCs from an open municipal solid waste (MSW) dump site studied using a flux chamber. Our study findings indicate that while planning for new landfill site in tropical meteorology, real-time emission data must be considered, rather than relying on modeled data. The formation of tropospheric ozone from emitted NMVOC has also been studied. Our result shows how an open landfill site acts as a source and adds to the tropospheric ozone for the airshed of a metropolitan city.     

Source profiles of volatile organic compounds associated with solvent use in Beijing,China

Compositions of volatile organic compound (VOC) emissions from painting applications and printing processes were sampled and measured by gas chromatography–mass spectrometry/flame ionization detection (GC–MS/FID) in Beijing. Toluene and C8 aromatics were the most abundant species, accounting for 76% of the total VOCs emitted from paint applications. The major species in printing emissions included heavier alkanes and aromatics, such as n-nonane, n-decane, n-undecane, toluene, and m/p-xylene. Measurements of VOCs obtained from furniture paint emissions in 2003 and 2007 suggest a quick decline in benzene levels associated with formulation changes in furniture paints during these years. A comparison of VOC source profiles for painting and printing between Beijing and other parts of the world showed significant region-specific discrepancies, probably because of different market demands and environmental standards. We conducted the evaluation of the source reactivities for various VOC emission sources. The ozone formation potential (OFP) for unit mass of VOCs source emissions is the highest for paint applications. Substituting solvent-based paints by water-based in Beijing will lead to an OFP reduction of 152,000 tons per year, which is more than 1/4 of the OFPs for VOCs emissions from vehicle exhaust in the city.