Steven H. Cadle's research while affiliated with General Motors Company and other places

Publications (93)

Article
This study proposed an interval mixed-integer semi-infinite programming (IMISIP) method for solid waste management under uncertainty. The uncertainty can be expressed as various constants, intervals, and functional intervals. The method is mainly based on the previous efforts on interval mixed-integer linear programming (IMILP) and semi-infinite pr...
Article
This study applied thermogravimetric analysis (TGA) technique to investigate the adsorption kinetics of vapor-phase mercury chloride (HgCl2) on activated carbon. HgCl2 is mainly emitted from the incineration of municipal solid waste (MSW) and causes severe adverse effects on human health and environment. Activated carbon injection (ACI) is the best...
Article
A particulate matter (PM) transport model is developed to investigate coarse PM (PM10), fine PM (PM2.5), and very fine PM (PM1) transport mechanisms in urban street canopies under low-wind conditions. Two common building layouts (i.e., the open and staggered street canopies) are considered. Large eddy simulations with the subgrid-scale stress model...
Article
The Coordinating Research Council (CRC) convened its 18th On-Road Vehicle Emissions Workshop March 31-April 2, 2008, with 104 presentations describing the most recent mobile source-related emissions research. In this paper we summarize the presentations from researchers whose efforts are improving our understanding of the contribution of mobile sou...
Article
Full-text available
The Coordinating Research Council, Inc. (CRC) held its 17th On-Road Vehicle Emissions Workshop in March 2007, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the role and contribution of mobile sources to ambient air qual...
Article
Full-text available
The Coordinating Research Council held its 16th workshop in March 2006, with 83 presentations describing the most recent mobile source-related emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the wor...
Article
Full-text available
The Coordinating Research Council held its 15th workshop in April 2005, with nearly 90 presentations describing the most recent mobile source-related emissions research. In this paper, the authors summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Partici...
Article
Weekly PM2.5 samples were simultaneously collected at a semi-residential (Tsinghua University) and a downtown (Chegongzhuang) site in Beijing from August 2001 through September 2002. The ambient mass concentration and chemical composition of PM2.5 were determined. Analyses including elemental composition, water-soluble ions, and organic and element...
Article
One-week integrated fine particulate matter (i.e., particles <2.5 microm in diameter; PM2.5) samples were collected continuously with a low-flow rate sampler at a downtown site (Chegongzhuang) and a residential site (Tsinghua University) in Beijing between July 1999 and June 2000. The annual average concentrations of organic carbon (OC) and element...
Article
Full-text available
Weekly PM<sub>2.5</sub> samples were collected for one year (1999-2000) in Beijing and Shanghai and the carbonaceous species analyzed to investigate and compare their time series patterns and possible sources in the two biggest cities of China. Weekly carbonaceous concentrations varied in wide ranges with 8.6-59µg m<sup>-3</sup> for OC and 1.5-25.4...
Article
Weekly PM2.5 samples were collected for one year in Beijing and Shanghai and the crustal elements analyzed to investigate the concentration levels and temporal variations of ambient fine mineral dust. The mass concentrations of Al, Si, Ca, Mg, and Fe exhibited similar significant weekly variations in both Beijing and Shanghai. The annual average PM...
Article
The Coordinating Research Council held its 14th Vehicle Emissions Workshop in March 2004, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories....
Article
Emission inventories are an essential tool for evaluating, managing, and regulating air pollution. Refinements and innovations in instruments that measure air pollutants, models that calculate emissions, and techniques for data management and uncertainty assessment are needed to enhance emission inventories. This workshop provided recommendations f...
Article
To understand the concentration levels and temporal variations of the mineral component of PM2.5 in the ambient air of Beijing, weeklong samples were simultaneously collected for one year at Qinghuayuan and Chegongzhuang. The concentrations of five major crustal elements Al, Si, Ca, Mg, and Fe exhibited similar significant weekly variations, with t...
Article
Full-text available
The Coordinating Research Council held its thirteenth Vehicle Emissions Workshop in April 2003, when results of the most recent on-road vehicle emissions research were presented. Ongoing work from researchers who are engaged in improving understanding of the contribution of mobile sources to ambient air quality and emission inventories is summarize...
Article
To understand concentration levels and sources of trace elements in PM2.5(particulate matter with aerodynamic diameters less than 2.5 microns) concentration and composition in the ambient air of Beijing, weekly samples were simultaneously collected for one year in Chegongzhuang and Qinghuayuan. Trace elements exhibited similar significant weekly va...
Article
In-use, light-duty vehicles were recruited in Cary, North Carolina for emissions testing on a transportable dynamometer in 1999. Two hundred forty-eight vehicles were tested in as received condition using the IM240 driving cycle. The study was conducted in two phases, a summer and winter phase, with half of the vehicles recruited during each phase....
Article
The Coordinating Research Council (CRC) held its 12th workshop in April 2002, with nearly 90 presentations on the most recent on-road vehicle emissions research. This paper summarizes the presentations from researchers who are engaged in improving understanding of the contribution of mobile sources to air quality. Participants in the workshop discu...
Article
Weekly PM2.5 samples were collected in Shanghai, China at two sites, Tongji University and Hainan Road. Sampling started in March 1999 and was conducted for 1 year. The ambient mass concentration and chemical composition of the PM2.5 were determined. Chemical analyses included elemental composition, water-soluble ions, and organic and elemental car...
Article
The water-soluble anionic species of PM2.5 at two sites in Beijing, China, were studied adopting a new technology to analyze the inorganic species and the water-soluble organic compounds (WSOC) in a run time. The two sites include one located downtown at an air quality monitoring station in Chegongzhuang with busy traffic, and one on the campus of...
Article
This paper describes the PM2.5 (participate matter with aerodynamic diameters less than 2.5 μm) concentration and composition in the ambient air of Beijing. Weekly samples were simultaneously collected for one year at the Chegongzhuang and Qinghuayuan sites in Beijing. The PM2.5 compositions at the two sampling sites were similar. The principal com...
Article
A year-long field study to characterize the ionic species in PM2.5 was carried out in Shanghai and Beijing, China, in 1999–2000. Weekly samples of PM2.5 were collected using a special low flow rate (0.4 l min−1) sampler. In Shanghai, SO42− NO3− and NH4+ were the dominant ionic species, which accounted for 46%, 18% and 17% of the total mass of ions,...
Article
The Coordinating Research Council (CRC) held its eleventh workshop in March 2001, focusing on results from the most recent real-world vehicle emissions research. We summarize the presentations from researchers engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants i...
Article
Weekly PM2.5 samples were simultaneously collected at a residential (Tsinghua University) and a downtown (Chegongzhuang) site in Beijing from July 1999 through September 2000. The ambient mass concentration and chemical composition of the PM2.5 were determined. Analyses included elemental composition, water-soluble ions, and organic and elemental c...
Article
The Coordinating Research Council (CRC) held its tenth workshop in March 2000, focusing on results from the most recent real-world vehicle emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to emission inventories. Participants in th...
Article
Twenty-four properly functioning and six high carbon monoxide emission light-duty gasoline vehicles were emission tested in Denver, CO, using the Federal Test Procedure (FTP), a hot start Unified Cycle (UC), and the REP05 driving cycles at 35 degrees F. All were 1990-1997 model year vehicles tested on both an oxygenated and a nonoxygenated fuel. PM...
Article
Current particulate matter (PM) emission factor models estimate brake wear particulate matter emission rates using data derived from asbestos brakes. However, most brake pads are now produced from nonasbestos materials. Little work has been performed on emissions from brakes using these materials. Therefore, a brake wear study was performed using s...
Article
Now that the U.S. Environmental Protection Agency has promulgated new National Ambient Air Quality Standards for PM2.5, work will begin on generating the data required to determine the sources of ambient PM2.5 and the magnitude of their contributions to air pollution. This paper summarizes the results of an Environmental Research Consortium program...
Article
In April 1999, the Coordinating Research Council sponsored a workshop focusing on our understanding of real-world emissions from motor vehicles. This summary presents the latest information on in-use light- and heavy-duty vehicle tailpipe and evaporative emissions, the effects of fuels on emissions, field programs designed to understand the contrib...
Article
In April 1999, the Coordinating Research Council sponsored a workshop focusing on our understanding of real-world emissions from motor vehicles. This summary presents the latest information on in-use light- and heavy-duty vehicle tailpipe and evaporative emissions, the effects of fuels on emissions, field programs designed to understand the contrib...
Article
A study of particulate matter (PM) emissions from in-use, light-duty vehicles was conducted during the summer of 1996 and the winter of 1997 in the Denver, CO, region. Vehicles were tested as received on chassis dynamometers on the Federal Test Procedure Urban Dynamometer Driving Schedule (UDDS) and the IM240 driving schedule. Both PM10 and regulat...
Article
A study to characterize particulate matter emissions from 195 in-use gasoline and diesel passenger vehicles was conducted during the summer of 1996 and the winter of 1997 in the Denver, Colorado region. Vehicles were tested as received on chassis dynamometers using the Federal Test Procedure (FTP) Urban Dynamometer Driving Schedule (UDDS). Both PM-...
Article
Full-text available
FTP-UDDS (urban dynamometer driving schedule) exhaust particulate matter (PM) emission rates were determined for 361 light-duty gasoline (LDGV) and 49 diesel passenger vehicles ranging in model year (MY) from 1965 to 1997. LDGVs were recruited into four MY categories. In addition, special effort was made to recruit LDGVs with visible smoke emission...
Article
The Coordinating Research Council (CRC) has sponsored a series of workshops over the last decade focusing on the most recent research on real-world vehicle emissions. This summary presents findings from the latest workshop by researchers engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the...
Article
One hundred three in-use vehicles identified as high hydrocarbon and/or carbon monoxide emitters by remote sensing and roadside visual, underhood checks during a 1995 South Coast Air Quality Management District program were tested on the IM240 cycle using a transportable dynamometer. Seventy-one of these vehicles were repaired as part of the progra...
Article
During the winter of 1994−1995, the State of Alaska Department of Environmental Conservation conducted a multi-faceted program designed to evaluate the impact of switching from regular gasoline to an E-10 fuel (gasoline with 10% ethanol) in Fairbanks. As part of that program, 10 in-use vehicles were tested on a chassis dynamometer at temperatures o...
Article
The Coordinating Research Council (CRC) has conducted a series of workshops on real-world vehicle emissions. This article summarizes findings from the most recent research regarding on-road emissions from mobile sources, presented at the CRC workshop held in March 1996. Among the topics discussed were efforts to improve and update emission models,...
Article
Twenty-three vehicles that were recruited by remote sensing and roadside inspection and maintenance (I/M) checks during the 1994 Clark and Washoe Remote Sensing Study (CAWRSS) were tested on the IM240 cycle using a transportable dynamometer. Six of these vehicles emitted visible smoke. Total gas-phase hydrocarbon (HC), carbon monoxide (CO), and nit...
Article
Second-by-second modal emissions data from a 73-vehicle fleet of 1990 and 1991 light duty cars and trucks driven on the Federal Test Procedure (FTP) driving cycle were examined to determine remote sensing errors of commission in identifying high emissions vehicles. Results are combined with a similar analysis of errors of omission based on modal FT...
Article
We will briefly discuss vehicle emissions and the vehicle emissions inventory before reviewing remote-sensing technology for exhaust emissions and remote-sensing applications that help characterize and minimize exhaust emissions in the real world. Remote sensing is the only method available that can measure the HC and CO exhaust emission rates of l...
Article
The CRC-APRAC On-Road Vehicle Emissions Workshop provided an informal atmosphere for the exchange of information on real-world vehicle emissions issues. Topics addressed included: emissions inventories; mobile source emission factor models; evaporative emissions; dynamometer studies of exhaust emissions; remote sensing studies; and tunnel studies o...
Article
White pine, Norway spruce and red spruce seedlings were exposed to nitric acid vapor concentrations of 10 to 120 ppb in constant stirred tank reactors. Nitric acid dry deposition rates were determined from both the change in nitric acid concentration in the reactor flow stream and from the amount of nitrogen recovered from the seedlings. Nitric aci...
Article
A conference was held on October 30-31,1990 to examine discrepancies between the output of vehicle emission factor models (MOBILE and EMFAC), field and laboratory measurements of vehicle emissions, and observed ratios of pollutants in urban atmospheres dominated by vehicle emissions. There was a general consensus that significant discrepancies exis...
Article
This report describes instrumentation that remotely measures the CO emissions from thousands of vehicles per day with a sensitivity of ± 1 percent CO in the exhaust, which is approximately 13 grams per mile of CO for new vehicles. A prototype of this instrument was used in Denver, Colorado in January 1989 during a study conducted in conjunction wit...
Chapter
Dry deposition refers to the transfer of gases and particles to ground-based surfaces, where they are removed. The two main reasons for studying dry deposition are: (1) The determination of the quantity of a species entering the environment. Interest usually centers on species such as SO4−2 or toxic trace metals that may harm components of aquatic...
Article
A field was conducted in Warren, MI, during the 1987/88 winter period to examined the reaction of HNO3 with particulate salt from road deicing. Samples of gases and particles were collected on a daily basis over a 4-month period. If HNO3 reacts with particulate salt, particles of sodium nitrate will be formed and gaseous hydrochloric acid will be r...
Article
Daily measurements the atmospheric cocnentrations of HNO3, NO3-, NO2, SO2, SO42−, NH4+, and several trace metals were made at the University of Michigan Biological Station over a 124-day period during the 1984–1985 winter. The composition of the daily precipitation was also determined. The relative contributions of scavenged NO3− and HNO3 to the pr...
Article
The General Motors Research Laboratories participated in both the field sampling and round-robin portions of the Carbonaceous Species Intercomparison study that was held in Glendora, CA, during the summer of 1986. Five samplers were operated during the field study. The average particulate elemental carbon (EC) concentrations determined from the fiv...
Article
Measurement methods for fine particle carbon were compared under field sampling conditions. Sampling methods included filtration, impaction, and adsorption-corrected filtration. Systems were operated side-by-side for nine consecutive days in the Los Angeles Basin. Analytical methods were compared separately. For organic carbon and total carbon, amb...
Article
Full-text available
The sources and sinks of organic carbon (OC) and elemental carbon (EC) were studied in the Detroit area during the 1983–1984 and 1984–1985 winters. Based on fuel usage and emission estimates, the largest carbon source was residential wood burning, which contributed 60% of OC emissions and 49% of EC emissions. Diesel vehicles contributed another 6%...
Article
Forest declines in Europe and the northeastern United States are widely believed to be associated with deposition of air pollutants, perhaps including nitric acid vapor. The experiments presented here, which were conducted in indoor chambers, involved measurement of steady-state rates of nitric acid deposition on foliage of seedlings of eastern whi...
Article
Particulate elemental carbon, organic carbon, and SO2−4 wintertime atmospheric concentrations were determined at a rural site in northern Michigan during two winters. Examination of the concentrations, based on both surface-wind direction and backward-trajectory analysis, indicated that concentrations were significantly influenced by the long-range...
Conference Paper
Unusual forest declines have been observed in Europe and at high elevations in the northeastern United States during the last several years. Since natural factors cannot explain all of the decline symptoms, researchers have concluded that air pollution is probably involved. Ozone damage, acid deposition, and excess nitrogen deposition have been pos...
Article
The retention of SO2 by nylon filters was determined in laboratory and field studies. Less than 4% of the SO2 was retained by nylon filters manufactured before May 1984. A change in filter material at that time appears to have greatly increased the retention of SO2 to values as high as 70%. Therefore, the SO2 retention by a nylon filter preceding a...
Article
Snowmelt and runoff were studied during the 1982-1983 and the 1983-1984 winters at the University of Michigan Biological Station, which is located near the northern tip of Michigan's lower peninsula. The first 50% of the snowpack acidity was released in meltwater and rainwater equal to 25% of the original snowpack water content. Interaction between...
Chapter
Wet deposition, dry deposition, and snowpack chemistry were studied during two winters at a rural location in northern Michigan and during one winter at an urban location in southern Michigan. The dry deposition rates were determined by measuring concentration changes in exposed snow samples. Dry deposition velocities were calculated from multi-day...
Article
Wet and dry deposition were monitored at the University of Michigan Biological Station in rural northern Michigan for three winters. Dry deposition was measured by both the conventional bucket method and by measuring increases in concentration in exposed, elevated snow samples. Average results of the two methods were in reasonable agreement. The cu...
Article
The composition of dew collected from a Teflon surface was compared to summer rainwater concentrations at a site in Warren, MI. This comparison showed that natural dew is similar to rainwater with the exception that dew has much higher concentrations of Ca2+ and Cl− and much lower acidity. Dry deposition rates of several species were measured to ar...
Article
Ambient particle and gas concentrations, wet deposition and dry deposition were measured in Warren, MI between December 18, 1983 and April 6, 1984. Dry deposition was measured to various surfaces in a cutoff bucket, including a snow surface, a snow/water surface during melting and a deionized water surface. Dry deposition velocities were calculated...
Article
A study of deposition velocities to snow was conducted during the 1982–1983 and 1983–1984 winters at the University of Michigan Biological Station in northern Michigan. Weekly measurements were made of dry deposition rates to snow and the atmospheric concentrations of the depositing species. SO2, with an average concentration of 2.2 ppb, was the do...
Article
Measurements of nitric acid, participate nitrate, strong aerosol acidity, and ammonia were made in Warren, Michigan for a one year period. Seasonal variations of these species were examined. The greatest variation was for ammonia, which was 8.5 times higher in summer than winter. The least variation was for particulate nitrate which had a summer ma...
Article
Measurements of ambient nitric acid and particulate nitrates were made by the dual-filter, denuder difference and penetration methods for 53 days during the summer of 1981 in Warren, Michigan. Nitric acid average concentrations determined by the penetration method (3.71 μg m−3) and the denuder difference method (3.11 μg m−3) were significantly lowe...
Article
Wet and dry deposition as collected by a bucket were measured at two sites in southeastern Michigan for two years. The precipitation had an average pH of 4.27 and a SO2−4 to NO−3 ratio of 2.0. Particulate dry deposition velocities of 0.6 cm s−1 for SO2−4 and NO−3 and > 2 cm s−1 for Cl−, Ca2+, Mg2+,Na+ and K+ were calculated. The ambient particle co...
Article
Recent reports have suggested that local sources exert a strong impact on precipitation chemistry. This idea was tested at two sites in SE Michigan which have very different local emissions: near the urban site SO2 emissions are 300 times higher, NOx emissions are 9 times higher, and TSP emissions are 56 times higher than near the rural site. Ambie...
Article
Weekly samples of wet deposition, dry deposition, and the snowpack were collected during the 1981–1982 winter at the University of Michigan Biological Station which is located near Pellston, Michigan. All the major acidic and basic species were determined. Comparison of the cumulative wet deposition acid loading to the snowpack loading as well as a...
Article
Snowcore and water samples were collected during the 1981 to 82 winter at two independent sites in Northern Michigan; the Little Pigeon River and McNearney Lake. Acidic and basic species were determined in all samples. Examination of the concentration vs depth profiles of snow cores showed that all species were stable in the snowpack until the spri...
Article
Dew samples were collected on inert surfaces during the summer and fall of 1982 in Warren, Michigan. This site is in a major urban area and is near heavily travelled roads. The median pH of the dew was 6.5, which can be compared to the average rain pH of 4.1 at the same site.-from Authors
Article
A comprehensive acid-deposition measuring station has been set up at the General Motors Technical Center site in Warren, Michigan. A second station is also being operated at a rural site near Lapeer, Michigan, which is approximately 54 km north of the Warren site. This report presents the results of this study for the June-September 1981 period.The...
Article
Several thermal and wet chemical methods of separating organic from elemental carbon in particulate samples were examined. It is concluded that none of them represents an ideal separation procedure and that only a method-dependent operational definition of organic and elemental carbon is possible at this time. The best separation method appears to...
Article
Measurements of ammonia, nitric acid and particulate nitrate were made at urban sites in Commerce City, Colorado, and Warren, Michigan and at rural locations near Abbeville, Louisiana and Luray, Virginia. The average ammonia and nitric acid concentrations over all sites were 1.7 ppb and 0.7 ppb, respectively. Diurnal patterns, determined at the Abb...
Article
Particulate elemental and organic carbon concentrations were determined on filters collected between 1972 and 1980 at ten United States’ sites representing urban, suburban, rural, and remote areas. The results showed that particulate elemental carbon is ubiquitous with mean concentrations ranging from 1.1 micrograms per cubic meter at the remote si...
Article
Methods for separating and measuring organic and elemental carbon in particulate samples collected on filters are evaluated. Included in this evaluation are solvent extraction, nitric acid digestion, optical absorption, and various thermal techniques. Emphasis is placed on the measurement of ambient samples, but samples from diesel- and gasoline-fu...
Article
The chemical and optical measurements collected at the General Motors Research Laboratories' site during the 1978 Denver “brown cloud” study are combined with data on energy consumption and emissions, as well as the use of tracer techniques, to estimate the contributions of the various sources to the fine paniculate mass (FPM) and the visual range...
Article
Size-segregated impactor samples of Denver's wintertime airborne particulate were analyzed for the major chemical species. These species are responsible for most of the pollution-related visibility reduction in Denver. Samples were collected three times a day during a 40-day field program in November-December, 1978. Each of the measured chemical sp...
Article
Size-segregated impactor samples of Denver’s wintertime airborne particulate were analyzed for the major chemical species. These species are responsible for most of the pollution-related visibility reduction in Denver. Samples were collected three times a day during a 40-day field program in November-December, 1978. Each of the measured chemical sp...
Article
Methods were investigated to measure exhaust emission rates of individual low-molecular-weight phenols from gasoline and diesel vehicles driven on a chassis dynamometer using the FTP driving cycle. An extraction procedure to isolate the phenols from exhaust scrubs was evaluated. Separation of individual phenols was done by gas chromatography, with...
Article
The sampling and chemical analysis of the ambient aerosol collected in Denver, CO, for a 40-day period during November and December, 1978 are described in this report. Parameters included 12-hr TSP measurements, 24-hr respirable and inhalable mass measurements, and 4-hr measurements of mass and chemical species (NO3−, SO4 =, NH4 +, organic and elem...
Article
A spectrophotometric method for total aliphatic amines and a gas chromatographic method for low molecular weight aliphatic amines were used to measure amine emissions in the exhaust of 17 cars which were driven on a chassis dynamometer using the 1975 FTP test. Because the extremely low concentration of amines resulted in problems with analytical se...
Conference Paper
An on-stream gas chromatographic technique was developed to analyze grab samples of diluted and undiluted vehicle exhaust for the reduced sulfur compounds which cause rotten-egg odors. This method was used to conduct a brief survey of two cars with modified carburetors, four customer cars with odor problems, and five experimental three-way catalyst...
Article
A massive experiment was conducted at the General Motors Proving Ground to measure the dispersion of sulfates generated by catalyst equipped vehicles. 352 cars equipped with catalysts and air pumps were driven on a 10 kilometer test track to provide a simulated freeway situation with a traffic density of 5462 cars/hour. Experiments were conducted o...
Article
General Motors has conducted an experiment at the Milford Proving Ground to measure the dispersion of automotive sulfate emissions from a simulated freeway. The 10 km North-South straightway, a straight, level track with a realistic median was used to simulate a four-lane freeway. A fleet of 352 cars driven on the track at 80 km/hr provided a traff...