William Modey | University of Illinois at Chicago (original) (raw)
Papers by William Modey
Journal of Microcolumn Separations, 1996
A quantitative comparison between off-line supercritical fluid extraction (SFE) and a classical s... more A quantitative comparison between off-line supercritical fluid extraction (SFE) and a classical solvent extraction of a limonoid compound is discussed. A two-level, three factor factorial analysis was used to optimize the variables, pressure, temperature, and the length of extraction time. By a statistical analysis of variance on the preliminary data collected, pressure and temperature were the significant variables influencing the yields of the limonoid cedrelone from the ground wood of Cedrela toona (Meliaceae). The cedrelone in the extracts was analyzed by capillary gas chromatography with flame ionization and mass spectrometric detection. On-line combination of micro-SFE with gas chromatography (SFE-GC) was also performed on the wood and bark to show the applicability of the technique in the analysis of semi-volatile components in natural products. Results for on-line and off-line SFE-GC were comparable and indicated that the on-line studies could be used to predict results obtainable from large scale SFE.
Journal of the Air & Waste Management Association, 2007
Both annual 24-h average and seasonal diurnal samples collected at NETL during the research progr... more Both annual 24-h average and seasonal diurnal samples collected at NETL during the research program have been analyzed. The fine particulate components determined include PM{sub 2.5} mass, ammonium sulfate, ammonium nitrate, elemental and organic carbonaceous material and trace elements. The analysis of the nitrate and organic material includes both the identification of nonvolatile material retained by the particle collection filter
Phytochemical Analysis, 1996
Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample prepa... more Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample preparation prior to the analysis of compounds in natural product matrices. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas and supercritical fluid chromatography. A number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and adsorption processes in the matrix. A wide range of applications is described for the extraction of carotenoids, lipids, flavour and fragrance compounds, steroids and triterpenes, alkaloids and mycotoxins.
Journal of the Air & Waste Management Association, 2002
The real-time ambient mass sampler (RAMS) is a continuous monitor based on particle concentrator,... more The real-time ambient mass sampler (RAMS) is a continuous monitor based on particle concentrator, denuder, drier, and tapered element oscillating microbalance (TEOM) monitor technology. It is designed to measure PM2.5 mass, including the semi-volatile species NH4NO3 and semi-volatile organic material, but not to measure PM2.5 water content. The performance of the RAMS in an urban environment with high humidity was evaluated during the July 1999 NARSTO-Northeast Oxidant and Particles Study (NEOPS) intensive study at the Baxter water treatment plant in Philadelphia, PA. The results obtained with the RAMS were compared to mass measurements made with a TEOM monitor and to constructed mass obtained with a Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) sampler designed to determine the chemical composition of fine particles, including the semi-volatile species. An average of 28% of the fine particulate material present during the study was semi-volatile organic material lost from a filter during particle collection, and 1% was NH4NO3 that was also lost from the particles during sampling. The remaining mass was dominantly nonvolatile (NH4)2SO4 (31%) and organic material (37%), with minor amounts of soot, crustal material, and nonvolatile NH4NO3. Comparison of the RAMS and PC-BOSS results indicated that the RAMS correctly monitored for fine particulate mass, including the semivolatile material. In contrast, the heated filter of the TEOM monitor did not measure the semi-volatile material. The comparison of the RAMS and PC-BOSS data had a precision of +/-4.1 microg/m3 (+/-9.6%). The precision of the RAMS data was limited by the uncertainty in the blank correction for the reversible adsorption of water by the charcoal-impregnated cellulose sorbent filter of the RAMS monitor. The precision of the measurement of fine particulate components by the PC-BOSS was +/-6-8%.
Journal of the Air & Waste Management Association, 2004
From October 1999 through September 2000, particulate matter (PM) with aerodynamic diameter &... more From October 1999 through September 2000, particulate matter (PM) with aerodynamic diameter > or =2.5 microm (PM2.5) mass and composition were measured at the National Energy Technology Laboratory Pittsburgh site, with a particle concentrator Brigham Young University-organic sampling system and a tapered element oscillating microbalance (TEOM) monitor. PM2.5 measurements had also been obtained with TEOM monitors located in the Pittsburgh, PA, area, and at sites in Ohio, including Steubenville, Columbus, and Athens. The PM data from all these sites were analyzed on high PM days; PM2.5 TEOM particulate mass at all sites was generally associated with transitions from locally high barometric pressure to lower pressure. Elevated concentrations occurred with transport of PM from outside the local region in advance of frontal passages as the local pressure decreased. During high-pressure periods, concentrations at the study sites were generally low throughout the study region. Further details related to this transport were obtained from surface weather maps and estimated back-trajectories using the hybrid single-particle Lagrangian integrated trajectory model associated with these time periods. These analyses indicated that transport of pollutants to the Pittsburgh site was generally from the west to the southwest. These results suggest that the Ohio River Valley and possible regions beyond act as a significant source of PM and its precursors in the Pittsburgh area and at the other regional sites included in this study.
Journal of the Air & Waste Management Association, 2007
Apportionment of primary and secondary pollutants during the summer 2001 Pittsburgh Air Quality S... more Apportionment of primary and secondary pollutants during the summer 2001 Pittsburgh Air Quality Study (PAQS) is reported. Several sites were included in PAQS, with the main site (the supersite) adjacent to the Carnegie Mellon University campus in Schenley Park. One of the additional sampling sites was located at the National Energy Technology Laboratory, located approximately 18 km southeast of downtown Pittsburgh. Fine particulate matter (PM2.5) mass, gas-phase volatile organic material (VOM), particulate semivolatile and nonvolatile organic material (NVOM), and ammonium sulfate were apportioned at the two sites into their primary and secondary contributions using the U.S. Environmental Protection Agency UNMIX 2.3 multivariate receptor modeling and analysis software. A portion of each of these species was identified as originating from gasoline and diesel primary mobile sources. Some of the organic material was formed from local secondary transformation processes, whereas the great majority of the secondary sulfate was associated with regional transformation contributions. The results indicated that the diurnal patterns of secondary gas-phase VOM and particulate semivolatile and NVOM were not correlated with secondary ammonium sulfate contributions but were associated with separate formation pathways. These findings are consistent with the bulk of the secondary ammonium sulfate in the Pittsburgh area being the result of contributions from distant transport and, thus, decoupled from local activity involving organic pollutants in the metropolitan area.
Journal of the Air & Waste Management Association, 2007
As part of the Gasoline/Diesel PM Split Study, relatively large fleets of gasoline vehicles and d... more As part of the Gasoline/Diesel PM Split Study, relatively large fleets of gasoline vehicles and diesel vehicles were tested on a chassis dynamometer to develop chemical source profiles for source attribution of atmospheric particulate matter in California's South Coast Air Basin. Gasoline vehicles were tested in cold-start and warm-start conditions, and diesel vehicles were tested through several driving cycles. Tailpipe emissions of particulate matter were analyzed for organic tracer compounds, including hopanes, steranes, and polycyclic aromatic hydrocarbons. Large intervehicle variation was seen in emission rate and composition, and results were averaged to examine the impacts of vehicle ages, weight classes, and driving cycles on the variation. Average profiles, weighted by mass emission rate, had much lower uncertainty than that associated with intervehicle variation. Mass emission rates and elemental carbon/organic carbon (EC/OC) ratios for gasoline vehicle age classes were influenced most by use of cold-start or warm-start driving cycle (factor of 2-7). Individual smoker vehicles had a large range of mass and EC/OC (factors of 40 and 625, respectively). Gasoline vehicle age averages, data on vehicle ages and miles traveled in the area, and several assumptions about smoker contributions were used to create emissions profiles representative of on-road vehicle fleets in the Los Angeles area in 2001. In the representative gasoline fleet profiles, variation was further reduced, with cold-start or warm-start and the representation of smoker vehicles making a difference of approximately a factor of two in mass emission rate and EC/OC. Diesel vehicle profiles were created on the basis of vehicle age, weight class, and driving cycle. Mass emission rate and EC/OC for diesel averages were influenced by vehicle age (factor of 2-5), weight class (factor of 2-7), and driving cycle (factor of 10-20). Absolute and relative emissions of molecular marker compounds showed levels of variation similar to those of mass and EC/OC.
Journal of the Air & Waste Management Association, 2007
A survey of monthly average concentrations of sulfur dioxide (SO2) and hydrogen sulfide (H2S) at ... more A survey of monthly average concentrations of sulfur dioxide (SO2) and hydrogen sulfide (H2S) at rural locations in western Canada (provinces of Alberta, British Columbia, and Saskatchewan) was conducted in 2001-2002, as part of an epidemiological study of the effects of oil and gas industry emissions on the health of cattle. Repeated measurements were obtained at some months and locations. We aimed to develop statistical models of the effect of oil and gas infrastructure on air concentrations. The regulatory authorities supplied the information on location of the different oil and gas facilities during the study period and, for Alberta, provided data on H2S content of wells and flaring volumes. Linear mixed effects models were used to relate observed concentrations to proximity and type of oil and gas infrastructure. Low concentrations were recorded; the monthly geometric mean was 0.1-0.2 ppb for H2S, and 0.3-1.3 ppb for SO2. Substantial variability between repeated measurements was observed. The precision of the measurement method was 0.005 ppb for both contaminants. There were seasonal trends in the concentrations, but the spatial variability was greater. This was explained, in part, by proximity to oil/gas/bitumen wells and (for SO2) gas plants. Wells within 2 km of monitoring stations had the greatest impact on measured concentrations. For H2S, 8% of between-location variability was explained by proximity to industrial sources of emissions; for SO2 this proportion was 18%. In Alberta, proximity to sour gas wells and flares was associated with elevated H2S concentrations; however, the estimate of the effect of sour gas wells in the immediate vicinity of monitoring stations was unstable. Our study was unable to control for all possible sources of the contaminants. However, the results suggest that oil and gas extraction activities contribute to air pollution in rural areas of western Canada.
Journal of the Air & Waste Management Association, 2007
A methodology for estimating vehicular emissions comprising a car simulator, a basic traffic mode... more A methodology for estimating vehicular emissions comprising a car simulator, a basic traffic model, and a geographical information system is capable of estimating vehicle emissions with high time and space resolution. Because of the extent of the work conducted, this article comprises two sections: In Part 1 of this work, we describe the system and its components and use examples for testing it. In Part 2 we will study in more detail the emissions of the sample fleet using the system and will make comparisons with another emission model. The experimental data for the car simulator is obtained using on-board measuring equipment and laboratory Fourier transform IR (FTIR) measurements with a dynamometer following typical driving cycles. The car simulator uses this data to generate emission factors every second. These emission factors, together with information on car activity and velocity profiles of highways and residential and arterial roads in Mexico City in conjunction with a basic traffic model, provide emissions per second of a sample fleet. A geographical information system is used to localize these road emissions.
Journal of the Air & Waste Management Association, 2007
A simple method for correcting for the loading effects of aethalometer data is presented. The for... more A simple method for correcting for the loading effects of aethalometer data is presented. The formula BC CORRECTED ϭ (1 ϩ k ⅐ ATN) ⅐ BC NONCORRECTED , where ATN is the attenuation and BC is black carbon, was used for correcting aethalometer data obtained from measurements at three different sites: a subway station in Helsinki, an urban background measurement station in Helsinki, and a rural station in Hyytiälä in central Finland. The BC data were compared with simultaneously measured aerosol volume concentrations (V). After the correction algorithm, the BC-to-V ratio remained relatively stable between consequent filter spots, which can be regarded as indirect evidence that the correction algorithm works. The k value calculated from the outdoor sites had a clear seasonal cycle that could be explained by darker aerosol in winter than in summer. When the contribution of BC to the total aerosol volume was high, the k factor was high and vice versa. In winter, the k values at all wavelengths were very close to that obtained from the subway station data. In summer, the k value was wavelength dependent and often negative. When the k value is negative, the noncorrected BC concentrations overestimated the true concentrations.
Journal of the Air & Waste Management Association, 2007
Vehicle emission inventory is a critical element for air quality study. This study created system... more Vehicle emission inventory is a critical element for air quality study. This study created systemic methods to establish a vehicle emission inventory in Chinese cities. The methods were used to obtain credible results of vehicle activity in Beijing and Shanghai. On the basis of the vehicle activity data, the International Vehicle Emission model is used to establish vehicle emission inventories. The emissions analysis indicates that 3 t of particulate matter (PM), 199 t of nitrogen oxides (NO(x)), 192 t of volatile organic compounds (VOCs), and 2403 t of carbon monoxide (CO) are emitted from on-road vehicles each day in Beijing, whereas 4 t of PM, 189 t of NO(x), 113 t of VOCs, and 1009 t of CO are emitted in Shanghai. Although common features were found in these two cities (many new passenger cars and a high taxi proportion in the fleet), the emission results are dissimilar because of the different local policy regarding vehicles. The method to quantify vehicle emission on an urban scale can be applied to other Chinese cities. Also, knowing how different policies can lead to diverse emissions is beneficial knowledge for other city governments.
Journal of the Air & Waste Management Association, 2007
In this paper, the deterioration of catalysts in small, four-stroke, spark-ignition engines is de... more In this paper, the deterioration of catalysts in small, four-stroke, spark-ignition engines is described. The laboratory testing performed followed a proven test method that mimics the lifetime of a small air-cooled utility engine operating under normal field conditions. The engines used were single-cylinder, 6.5-hp, side-valve engines. These engines have a nominal 125-hr lifetime. The effectiveness of the catalysts was determined by testing exhaust emissions before and after the catalyst to determine the catalyst's efficiency. This was done several times during the lifetime of the engines to determine the deterioration in the performance of the catalysts at lowering pollutant emissions. Additional testing was performed on the catalysts to determine wear patterns, contamination, and recoverable activity. The results indicate that considerable catalyst deterioration is occurring over the lifetime of the engine. The results reveal that soot buildup, poisons, and active surface loss appear to be the contributing factors to the deterioration. These results were determined after analyzing the exhaust emissions data, scanning electron microscope results analysis, and the impact of regeneration attempts. An ANOVA statistical analysis was performed, and it was determined that the emissions are also impacted, to some degree, by time and the engine itself.
Journal of the Air & Waste Management Association, 2007
A sensitivity analysis was conducted to characterize sources of uncertainty in results of a molec... more A sensitivity analysis was conducted to characterize sources of uncertainty in results of a molecular marker source apportionment model of ambient particulate matter using mobile source emissions profiles obtained as part of the Gasoline/Diesel PM Split Study. A chemical mass balance (CMB) model was used to determine source contributions to samples of fine particulate matter (PM2.5) collected over 3 weeks at two sites in the Los Angeles area in July 2001. The ambient samples were composited for organic compound analysis by the day of the week to investigate weekly trends in source contributions. The sensitivity analysis specifically examined the impact of the uncertainty in mobile source emissions profiles on the CMB model results. The key parameter impacting model sensitivity was the source profile for gasoline smoker vehicles. High-emitting gasoline smoker vehicles with visible plumes were seen to be a significant source of PM in the area, but use of different measured profiles for smoker vehicles in the model gave very different results for apportionment of gasoline, diesel, and smoker vehicle tailpipe emissions. In addition, the contributions of gasoline and diesel emissions to total ambient PM varied as a function of the site and the day of the week.
Journal of the Air & Waste Management Association, 2007
Alkylphenol polyethoxylates (APEOs) have been widely used as nonionic surfactants in a variety of... more Alkylphenol polyethoxylates (APEOs) have been widely used as nonionic surfactants in a variety of industrial and commercial products. Typical compounds are nonylphenol polyethoxylates (NPEOs) and octylphenol polyethoxylates (OPEOs), which serve as precursors to nonylphenol (NP) and octylphenol (OP), respectively. NP and 4-t-OP are known to have endocrine disrupting effects on fish (medaka, Oryzias latipes), so it is important to know the concentrations of APEOs in the environment. Because the analytical characteristics of these compounds depend on the length of the ethoxy chain, it is necessary to use appropriate compounds as internal standards or surrogates. We synthesized two 13C-labeled surrogate compounds and used these compounds as internal standards to determine NPEOs and OPEOs by high-performance liquid chromatography (LC)-mass spectrometry. Method detection limits were 0.015 microg/L for NP (2)EO to 0.037 microg/L for NP(12)EO, and 0.011 microg/L for OP(3,6)EO to 0.024 microg/L for OP (4)EO. NPEO concentrations in water from a sewage treatment plant were less than 0.05-0.52 microg/L for final effluent and 1.2-15 microg/L for influent. OPEO concentrations were less than 0.05-0.15 microg/L for the final effluent and less than 0.05-1.1 microg/L for influent.
Journal of the Air & Waste Management Association, 2007
The 1999/31 Elemental Carbon Directive sets strict rules on the disposal of untreated municipal s... more The 1999/31 Elemental Carbon Directive sets strict rules on the disposal of untreated municipal solid waste in the European Union countries and forces a reduction of the biodegradable quantities disposed off to landfills up to 35% of the amount produced in 1995 in the coming decade. More environmentally friendly waste management options shall be promoted under the framework of the Community Waste Strategy ([96] 399 Final). In this context, the production and thermal use of solid recovered fuels (SRFs), derived from nonhazardous bioresidues and mixed- and mono-waste streams, could be a key element in a future waste management system. Within the scope of the European Demonstration Project, RECOFUEL, SRF cocombustion was demonstrated in two large-scale lignite-fired coal boilers at RWE power station in Weisweiler, Germany. As a consequence of the high biogenic share of the cocombusted material, this approach can be considered beneficial following European Directive 2001/77/EC on electricity from renewable energy sources (directive). During the experimental campaign, the share of SRF in the overall thermal input was adjusted to approximately 2%, resulting into a feeding rate of approximately 25 t/hr. The measurement campaign included boiler measurements in different locations, fuel and ash sampling, and its characterization. The corrosion rates were monitored by dedicated corrosion probes. The overall results showed no significant influence of SRF cocombustion on boiler operation, emissions behavior, and residues quality for the thermal shares applied. Also, no effect of the increased chlorine concentration of the recovered fuel was observed in the flue gas path after the desulfurization unit.
Journal of the Air & Waste Management Association, 2007
Journal of Geophysical Research, 2003
1] The first of the U.S. Environmental Protection Agency's (EPA) Particulate Matter (PM) Supersit... more 1] The first of the U.S. Environmental Protection Agency's (EPA) Particulate Matter (PM) Supersites projects was established in Atlanta, GA, during the summer of 1999 in conjunction with the Southern Oxidants Study. The short-term primary focus was a one month intensive field campaign to evaluate advanced PM measurement methods for measuring PM mass and the chemical and physical properties of PM. Long-term objectives are being met through coordination and cooperation with existing programs in Atlanta and the southeastern United States. Three categories of PM instruments were deployed during August 1999: time-integrated or discrete filter-based methods like those used in EPA's PM2.5 Chemical Speciation Network; continuous or semicontinuous species specific methods, most of which are still in development; and single particle mass spectrometers, the most advanced methods looking at the chemical composition of single particles. The focus of this paper is on comparison of the discrete filter-based methods. Samples were collected by 12 discrete filter-based samplers on an every other day basis during the study period at the Jefferson Street Southeastern Aerosol Research and Characterization (SEARCH) study site. Samples were analyzed for PM2.5 mass, sulfate, nitrate, ammonium, organic carbon, elemental carbon, and trace elements, the latter by XRF. Samplers used a variety of filters; denuder-filter combinations in the case of nitrate and organic carbon, particle size fractionating devices, and flow rates. Ambient concentrations for most species were sufficiently above detection limits for testing comparability among samplers, with nitrate being the most notable exception for the major components having an average reported value of 0.5 mg/m 3 . Several trace species, e.g., As and Pb, also were often below limits of detection of the analysis method. Results indicate that real differences exist among the samplers tested for most species, with sulfate and ammonium being the exceptions, under the conditions tested. Differences are due to sampler design, and in the case of elemental carbon, also due to the use of different chemical analysis methods. Comparability among most of the samplers for a given species was: mass (±20%); sulfate (±10%); nitrate (±30-35%); ammonium (±10-15%); organic carbon either with or without denuders (±20%) or including samplers both with and without denuders (±35-45%); elemental carbon (±20 to ±200%, the latter if different analysis methods are used); and minor and trace elements (±20-30%). A net organic carbon-sampling artifact on quartz-fiber filters was estimated from the comparison of denuded versus undenuded samples and is in the range of 1-4 mg/m 3 . Citation: Solomon, P., et al., Comparison of integrated samplers for mass and composition during the 1999 Atlanta Supersites project,
Advances in Environmental Research, 2003
This paper reports on the results from the first 6 months (from November 1999 to April 2000) of a... more This paper reports on the results from the first 6 months (from November 1999 to April 2000) of an ongoing monitoring study of fine particulate air pollutants at the Department of Energy's Office of Science and Technology (OST) NETL sampling site, 30 km southwest of Pittsburgh city center, Pennsylvania. This study is part of a 2-year sampling program for PM characterization, under the auspices of The University Coal Research Program of the National Energy Technology Laboratory (NETL), US Department of Energy in Pittsburgh, PA, USA. Samples were collected daily with a Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) to determine PM composition, including the semi-volatile organic compounds (SVOC) and ammonium nitrate lost 2.3 from particles during sampling. Average fine particulate composition during the 6-month period was: constructed PM , 19.4 mg m ; ammonium sulfate 4.3 mg m ; non-volatile organic material, 6.9 mg m ; elemental carbon, y3 y3 y3 2.3 0.4 mg m ; SVOC lost from particles during sampling, 6.1 mg m ; retained ammonium nitrate, 1.4 mg m ; lost y3 y3 y3 ammonium nitrate, 0.3 mg m . Results from the PC-BOSS sampler are also compared with those obtained from a y3 Federal Reference Method PM sampler, and a Tapered Element Oscillating Microbalance monitor, both of which 2.5
Journal of Microcolumn Separations, 1996
A quantitative comparison between off-line supercritical fluid extraction (SFE) and a classical s... more A quantitative comparison between off-line supercritical fluid extraction (SFE) and a classical solvent extraction of a limonoid compound is discussed. A two-level, three factor factorial analysis was used to optimize the variables, pressure, temperature, and the length of extraction time. By a statistical analysis of variance on the preliminary data collected, pressure and temperature were the significant variables influencing the yields of the limonoid cedrelone from the ground wood of Cedrela toona (Meliaceae). The cedrelone in the extracts was analyzed by capillary gas chromatography with flame ionization and mass spectrometric detection. On-line combination of micro-SFE with gas chromatography (SFE-GC) was also performed on the wood and bark to show the applicability of the technique in the analysis of semi-volatile components in natural products. Results for on-line and off-line SFE-GC were comparable and indicated that the on-line studies could be used to predict results obtainable from large scale SFE.
Journal of the Air & Waste Management Association, 2007
Both annual 24-h average and seasonal diurnal samples collected at NETL during the research progr... more Both annual 24-h average and seasonal diurnal samples collected at NETL during the research program have been analyzed. The fine particulate components determined include PM{sub 2.5} mass, ammonium sulfate, ammonium nitrate, elemental and organic carbonaceous material and trace elements. The analysis of the nitrate and organic material includes both the identification of nonvolatile material retained by the particle collection filter
Phytochemical Analysis, 1996
Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample prepa... more Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample preparation prior to the analysis of compounds in natural product matrices. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas and supercritical fluid chromatography. A number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and adsorption processes in the matrix. A wide range of applications is described for the extraction of carotenoids, lipids, flavour and fragrance compounds, steroids and triterpenes, alkaloids and mycotoxins.
Journal of the Air & Waste Management Association, 2002
The real-time ambient mass sampler (RAMS) is a continuous monitor based on particle concentrator,... more The real-time ambient mass sampler (RAMS) is a continuous monitor based on particle concentrator, denuder, drier, and tapered element oscillating microbalance (TEOM) monitor technology. It is designed to measure PM2.5 mass, including the semi-volatile species NH4NO3 and semi-volatile organic material, but not to measure PM2.5 water content. The performance of the RAMS in an urban environment with high humidity was evaluated during the July 1999 NARSTO-Northeast Oxidant and Particles Study (NEOPS) intensive study at the Baxter water treatment plant in Philadelphia, PA. The results obtained with the RAMS were compared to mass measurements made with a TEOM monitor and to constructed mass obtained with a Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) sampler designed to determine the chemical composition of fine particles, including the semi-volatile species. An average of 28% of the fine particulate material present during the study was semi-volatile organic material lost from a filter during particle collection, and 1% was NH4NO3 that was also lost from the particles during sampling. The remaining mass was dominantly nonvolatile (NH4)2SO4 (31%) and organic material (37%), with minor amounts of soot, crustal material, and nonvolatile NH4NO3. Comparison of the RAMS and PC-BOSS results indicated that the RAMS correctly monitored for fine particulate mass, including the semivolatile material. In contrast, the heated filter of the TEOM monitor did not measure the semi-volatile material. The comparison of the RAMS and PC-BOSS data had a precision of +/-4.1 microg/m3 (+/-9.6%). The precision of the RAMS data was limited by the uncertainty in the blank correction for the reversible adsorption of water by the charcoal-impregnated cellulose sorbent filter of the RAMS monitor. The precision of the measurement of fine particulate components by the PC-BOSS was +/-6-8%.
Journal of the Air & Waste Management Association, 2004
From October 1999 through September 2000, particulate matter (PM) with aerodynamic diameter &... more From October 1999 through September 2000, particulate matter (PM) with aerodynamic diameter > or =2.5 microm (PM2.5) mass and composition were measured at the National Energy Technology Laboratory Pittsburgh site, with a particle concentrator Brigham Young University-organic sampling system and a tapered element oscillating microbalance (TEOM) monitor. PM2.5 measurements had also been obtained with TEOM monitors located in the Pittsburgh, PA, area, and at sites in Ohio, including Steubenville, Columbus, and Athens. The PM data from all these sites were analyzed on high PM days; PM2.5 TEOM particulate mass at all sites was generally associated with transitions from locally high barometric pressure to lower pressure. Elevated concentrations occurred with transport of PM from outside the local region in advance of frontal passages as the local pressure decreased. During high-pressure periods, concentrations at the study sites were generally low throughout the study region. Further details related to this transport were obtained from surface weather maps and estimated back-trajectories using the hybrid single-particle Lagrangian integrated trajectory model associated with these time periods. These analyses indicated that transport of pollutants to the Pittsburgh site was generally from the west to the southwest. These results suggest that the Ohio River Valley and possible regions beyond act as a significant source of PM and its precursors in the Pittsburgh area and at the other regional sites included in this study.
Journal of the Air & Waste Management Association, 2007
Apportionment of primary and secondary pollutants during the summer 2001 Pittsburgh Air Quality S... more Apportionment of primary and secondary pollutants during the summer 2001 Pittsburgh Air Quality Study (PAQS) is reported. Several sites were included in PAQS, with the main site (the supersite) adjacent to the Carnegie Mellon University campus in Schenley Park. One of the additional sampling sites was located at the National Energy Technology Laboratory, located approximately 18 km southeast of downtown Pittsburgh. Fine particulate matter (PM2.5) mass, gas-phase volatile organic material (VOM), particulate semivolatile and nonvolatile organic material (NVOM), and ammonium sulfate were apportioned at the two sites into their primary and secondary contributions using the U.S. Environmental Protection Agency UNMIX 2.3 multivariate receptor modeling and analysis software. A portion of each of these species was identified as originating from gasoline and diesel primary mobile sources. Some of the organic material was formed from local secondary transformation processes, whereas the great majority of the secondary sulfate was associated with regional transformation contributions. The results indicated that the diurnal patterns of secondary gas-phase VOM and particulate semivolatile and NVOM were not correlated with secondary ammonium sulfate contributions but were associated with separate formation pathways. These findings are consistent with the bulk of the secondary ammonium sulfate in the Pittsburgh area being the result of contributions from distant transport and, thus, decoupled from local activity involving organic pollutants in the metropolitan area.
Journal of the Air & Waste Management Association, 2007
As part of the Gasoline/Diesel PM Split Study, relatively large fleets of gasoline vehicles and d... more As part of the Gasoline/Diesel PM Split Study, relatively large fleets of gasoline vehicles and diesel vehicles were tested on a chassis dynamometer to develop chemical source profiles for source attribution of atmospheric particulate matter in California's South Coast Air Basin. Gasoline vehicles were tested in cold-start and warm-start conditions, and diesel vehicles were tested through several driving cycles. Tailpipe emissions of particulate matter were analyzed for organic tracer compounds, including hopanes, steranes, and polycyclic aromatic hydrocarbons. Large intervehicle variation was seen in emission rate and composition, and results were averaged to examine the impacts of vehicle ages, weight classes, and driving cycles on the variation. Average profiles, weighted by mass emission rate, had much lower uncertainty than that associated with intervehicle variation. Mass emission rates and elemental carbon/organic carbon (EC/OC) ratios for gasoline vehicle age classes were influenced most by use of cold-start or warm-start driving cycle (factor of 2-7). Individual smoker vehicles had a large range of mass and EC/OC (factors of 40 and 625, respectively). Gasoline vehicle age averages, data on vehicle ages and miles traveled in the area, and several assumptions about smoker contributions were used to create emissions profiles representative of on-road vehicle fleets in the Los Angeles area in 2001. In the representative gasoline fleet profiles, variation was further reduced, with cold-start or warm-start and the representation of smoker vehicles making a difference of approximately a factor of two in mass emission rate and EC/OC. Diesel vehicle profiles were created on the basis of vehicle age, weight class, and driving cycle. Mass emission rate and EC/OC for diesel averages were influenced by vehicle age (factor of 2-5), weight class (factor of 2-7), and driving cycle (factor of 10-20). Absolute and relative emissions of molecular marker compounds showed levels of variation similar to those of mass and EC/OC.
Journal of the Air & Waste Management Association, 2007
A survey of monthly average concentrations of sulfur dioxide (SO2) and hydrogen sulfide (H2S) at ... more A survey of monthly average concentrations of sulfur dioxide (SO2) and hydrogen sulfide (H2S) at rural locations in western Canada (provinces of Alberta, British Columbia, and Saskatchewan) was conducted in 2001-2002, as part of an epidemiological study of the effects of oil and gas industry emissions on the health of cattle. Repeated measurements were obtained at some months and locations. We aimed to develop statistical models of the effect of oil and gas infrastructure on air concentrations. The regulatory authorities supplied the information on location of the different oil and gas facilities during the study period and, for Alberta, provided data on H2S content of wells and flaring volumes. Linear mixed effects models were used to relate observed concentrations to proximity and type of oil and gas infrastructure. Low concentrations were recorded; the monthly geometric mean was 0.1-0.2 ppb for H2S, and 0.3-1.3 ppb for SO2. Substantial variability between repeated measurements was observed. The precision of the measurement method was 0.005 ppb for both contaminants. There were seasonal trends in the concentrations, but the spatial variability was greater. This was explained, in part, by proximity to oil/gas/bitumen wells and (for SO2) gas plants. Wells within 2 km of monitoring stations had the greatest impact on measured concentrations. For H2S, 8% of between-location variability was explained by proximity to industrial sources of emissions; for SO2 this proportion was 18%. In Alberta, proximity to sour gas wells and flares was associated with elevated H2S concentrations; however, the estimate of the effect of sour gas wells in the immediate vicinity of monitoring stations was unstable. Our study was unable to control for all possible sources of the contaminants. However, the results suggest that oil and gas extraction activities contribute to air pollution in rural areas of western Canada.
Journal of the Air & Waste Management Association, 2007
A methodology for estimating vehicular emissions comprising a car simulator, a basic traffic mode... more A methodology for estimating vehicular emissions comprising a car simulator, a basic traffic model, and a geographical information system is capable of estimating vehicle emissions with high time and space resolution. Because of the extent of the work conducted, this article comprises two sections: In Part 1 of this work, we describe the system and its components and use examples for testing it. In Part 2 we will study in more detail the emissions of the sample fleet using the system and will make comparisons with another emission model. The experimental data for the car simulator is obtained using on-board measuring equipment and laboratory Fourier transform IR (FTIR) measurements with a dynamometer following typical driving cycles. The car simulator uses this data to generate emission factors every second. These emission factors, together with information on car activity and velocity profiles of highways and residential and arterial roads in Mexico City in conjunction with a basic traffic model, provide emissions per second of a sample fleet. A geographical information system is used to localize these road emissions.
Journal of the Air & Waste Management Association, 2007
A simple method for correcting for the loading effects of aethalometer data is presented. The for... more A simple method for correcting for the loading effects of aethalometer data is presented. The formula BC CORRECTED ϭ (1 ϩ k ⅐ ATN) ⅐ BC NONCORRECTED , where ATN is the attenuation and BC is black carbon, was used for correcting aethalometer data obtained from measurements at three different sites: a subway station in Helsinki, an urban background measurement station in Helsinki, and a rural station in Hyytiälä in central Finland. The BC data were compared with simultaneously measured aerosol volume concentrations (V). After the correction algorithm, the BC-to-V ratio remained relatively stable between consequent filter spots, which can be regarded as indirect evidence that the correction algorithm works. The k value calculated from the outdoor sites had a clear seasonal cycle that could be explained by darker aerosol in winter than in summer. When the contribution of BC to the total aerosol volume was high, the k factor was high and vice versa. In winter, the k values at all wavelengths were very close to that obtained from the subway station data. In summer, the k value was wavelength dependent and often negative. When the k value is negative, the noncorrected BC concentrations overestimated the true concentrations.
Journal of the Air & Waste Management Association, 2007
Vehicle emission inventory is a critical element for air quality study. This study created system... more Vehicle emission inventory is a critical element for air quality study. This study created systemic methods to establish a vehicle emission inventory in Chinese cities. The methods were used to obtain credible results of vehicle activity in Beijing and Shanghai. On the basis of the vehicle activity data, the International Vehicle Emission model is used to establish vehicle emission inventories. The emissions analysis indicates that 3 t of particulate matter (PM), 199 t of nitrogen oxides (NO(x)), 192 t of volatile organic compounds (VOCs), and 2403 t of carbon monoxide (CO) are emitted from on-road vehicles each day in Beijing, whereas 4 t of PM, 189 t of NO(x), 113 t of VOCs, and 1009 t of CO are emitted in Shanghai. Although common features were found in these two cities (many new passenger cars and a high taxi proportion in the fleet), the emission results are dissimilar because of the different local policy regarding vehicles. The method to quantify vehicle emission on an urban scale can be applied to other Chinese cities. Also, knowing how different policies can lead to diverse emissions is beneficial knowledge for other city governments.
Journal of the Air & Waste Management Association, 2007
In this paper, the deterioration of catalysts in small, four-stroke, spark-ignition engines is de... more In this paper, the deterioration of catalysts in small, four-stroke, spark-ignition engines is described. The laboratory testing performed followed a proven test method that mimics the lifetime of a small air-cooled utility engine operating under normal field conditions. The engines used were single-cylinder, 6.5-hp, side-valve engines. These engines have a nominal 125-hr lifetime. The effectiveness of the catalysts was determined by testing exhaust emissions before and after the catalyst to determine the catalyst's efficiency. This was done several times during the lifetime of the engines to determine the deterioration in the performance of the catalysts at lowering pollutant emissions. Additional testing was performed on the catalysts to determine wear patterns, contamination, and recoverable activity. The results indicate that considerable catalyst deterioration is occurring over the lifetime of the engine. The results reveal that soot buildup, poisons, and active surface loss appear to be the contributing factors to the deterioration. These results were determined after analyzing the exhaust emissions data, scanning electron microscope results analysis, and the impact of regeneration attempts. An ANOVA statistical analysis was performed, and it was determined that the emissions are also impacted, to some degree, by time and the engine itself.
Journal of the Air & Waste Management Association, 2007
A sensitivity analysis was conducted to characterize sources of uncertainty in results of a molec... more A sensitivity analysis was conducted to characterize sources of uncertainty in results of a molecular marker source apportionment model of ambient particulate matter using mobile source emissions profiles obtained as part of the Gasoline/Diesel PM Split Study. A chemical mass balance (CMB) model was used to determine source contributions to samples of fine particulate matter (PM2.5) collected over 3 weeks at two sites in the Los Angeles area in July 2001. The ambient samples were composited for organic compound analysis by the day of the week to investigate weekly trends in source contributions. The sensitivity analysis specifically examined the impact of the uncertainty in mobile source emissions profiles on the CMB model results. The key parameter impacting model sensitivity was the source profile for gasoline smoker vehicles. High-emitting gasoline smoker vehicles with visible plumes were seen to be a significant source of PM in the area, but use of different measured profiles for smoker vehicles in the model gave very different results for apportionment of gasoline, diesel, and smoker vehicle tailpipe emissions. In addition, the contributions of gasoline and diesel emissions to total ambient PM varied as a function of the site and the day of the week.
Journal of the Air & Waste Management Association, 2007
Alkylphenol polyethoxylates (APEOs) have been widely used as nonionic surfactants in a variety of... more Alkylphenol polyethoxylates (APEOs) have been widely used as nonionic surfactants in a variety of industrial and commercial products. Typical compounds are nonylphenol polyethoxylates (NPEOs) and octylphenol polyethoxylates (OPEOs), which serve as precursors to nonylphenol (NP) and octylphenol (OP), respectively. NP and 4-t-OP are known to have endocrine disrupting effects on fish (medaka, Oryzias latipes), so it is important to know the concentrations of APEOs in the environment. Because the analytical characteristics of these compounds depend on the length of the ethoxy chain, it is necessary to use appropriate compounds as internal standards or surrogates. We synthesized two 13C-labeled surrogate compounds and used these compounds as internal standards to determine NPEOs and OPEOs by high-performance liquid chromatography (LC)-mass spectrometry. Method detection limits were 0.015 microg/L for NP (2)EO to 0.037 microg/L for NP(12)EO, and 0.011 microg/L for OP(3,6)EO to 0.024 microg/L for OP (4)EO. NPEO concentrations in water from a sewage treatment plant were less than 0.05-0.52 microg/L for final effluent and 1.2-15 microg/L for influent. OPEO concentrations were less than 0.05-0.15 microg/L for the final effluent and less than 0.05-1.1 microg/L for influent.
Journal of the Air & Waste Management Association, 2007
The 1999/31 Elemental Carbon Directive sets strict rules on the disposal of untreated municipal s... more The 1999/31 Elemental Carbon Directive sets strict rules on the disposal of untreated municipal solid waste in the European Union countries and forces a reduction of the biodegradable quantities disposed off to landfills up to 35% of the amount produced in 1995 in the coming decade. More environmentally friendly waste management options shall be promoted under the framework of the Community Waste Strategy ([96] 399 Final). In this context, the production and thermal use of solid recovered fuels (SRFs), derived from nonhazardous bioresidues and mixed- and mono-waste streams, could be a key element in a future waste management system. Within the scope of the European Demonstration Project, RECOFUEL, SRF cocombustion was demonstrated in two large-scale lignite-fired coal boilers at RWE power station in Weisweiler, Germany. As a consequence of the high biogenic share of the cocombusted material, this approach can be considered beneficial following European Directive 2001/77/EC on electricity from renewable energy sources (directive). During the experimental campaign, the share of SRF in the overall thermal input was adjusted to approximately 2%, resulting into a feeding rate of approximately 25 t/hr. The measurement campaign included boiler measurements in different locations, fuel and ash sampling, and its characterization. The corrosion rates were monitored by dedicated corrosion probes. The overall results showed no significant influence of SRF cocombustion on boiler operation, emissions behavior, and residues quality for the thermal shares applied. Also, no effect of the increased chlorine concentration of the recovered fuel was observed in the flue gas path after the desulfurization unit.
Journal of the Air & Waste Management Association, 2007
Journal of Geophysical Research, 2003
1] The first of the U.S. Environmental Protection Agency's (EPA) Particulate Matter (PM) Supersit... more 1] The first of the U.S. Environmental Protection Agency's (EPA) Particulate Matter (PM) Supersites projects was established in Atlanta, GA, during the summer of 1999 in conjunction with the Southern Oxidants Study. The short-term primary focus was a one month intensive field campaign to evaluate advanced PM measurement methods for measuring PM mass and the chemical and physical properties of PM. Long-term objectives are being met through coordination and cooperation with existing programs in Atlanta and the southeastern United States. Three categories of PM instruments were deployed during August 1999: time-integrated or discrete filter-based methods like those used in EPA's PM2.5 Chemical Speciation Network; continuous or semicontinuous species specific methods, most of which are still in development; and single particle mass spectrometers, the most advanced methods looking at the chemical composition of single particles. The focus of this paper is on comparison of the discrete filter-based methods. Samples were collected by 12 discrete filter-based samplers on an every other day basis during the study period at the Jefferson Street Southeastern Aerosol Research and Characterization (SEARCH) study site. Samples were analyzed for PM2.5 mass, sulfate, nitrate, ammonium, organic carbon, elemental carbon, and trace elements, the latter by XRF. Samplers used a variety of filters; denuder-filter combinations in the case of nitrate and organic carbon, particle size fractionating devices, and flow rates. Ambient concentrations for most species were sufficiently above detection limits for testing comparability among samplers, with nitrate being the most notable exception for the major components having an average reported value of 0.5 mg/m 3 . Several trace species, e.g., As and Pb, also were often below limits of detection of the analysis method. Results indicate that real differences exist among the samplers tested for most species, with sulfate and ammonium being the exceptions, under the conditions tested. Differences are due to sampler design, and in the case of elemental carbon, also due to the use of different chemical analysis methods. Comparability among most of the samplers for a given species was: mass (±20%); sulfate (±10%); nitrate (±30-35%); ammonium (±10-15%); organic carbon either with or without denuders (±20%) or including samplers both with and without denuders (±35-45%); elemental carbon (±20 to ±200%, the latter if different analysis methods are used); and minor and trace elements (±20-30%). A net organic carbon-sampling artifact on quartz-fiber filters was estimated from the comparison of denuded versus undenuded samples and is in the range of 1-4 mg/m 3 . Citation: Solomon, P., et al., Comparison of integrated samplers for mass and composition during the 1999 Atlanta Supersites project,
Advances in Environmental Research, 2003
This paper reports on the results from the first 6 months (from November 1999 to April 2000) of a... more This paper reports on the results from the first 6 months (from November 1999 to April 2000) of an ongoing monitoring study of fine particulate air pollutants at the Department of Energy's Office of Science and Technology (OST) NETL sampling site, 30 km southwest of Pittsburgh city center, Pennsylvania. This study is part of a 2-year sampling program for PM characterization, under the auspices of The University Coal Research Program of the National Energy Technology Laboratory (NETL), US Department of Energy in Pittsburgh, PA, USA. Samples were collected daily with a Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) to determine PM composition, including the semi-volatile organic compounds (SVOC) and ammonium nitrate lost 2.3 from particles during sampling. Average fine particulate composition during the 6-month period was: constructed PM , 19.4 mg m ; ammonium sulfate 4.3 mg m ; non-volatile organic material, 6.9 mg m ; elemental carbon, y3 y3 y3 2.3 0.4 mg m ; SVOC lost from particles during sampling, 6.1 mg m ; retained ammonium nitrate, 1.4 mg m ; lost y3 y3 y3 ammonium nitrate, 0.3 mg m . Results from the PC-BOSS sampler are also compared with those obtained from a y3 Federal Reference Method PM sampler, and a Tapered Element Oscillating Microbalance monitor, both of which 2.5