Analytical chemistry and vehicle emissions - American Chemical Society

Dennis Schuetzle and Trescott E. Jensen Ford Motor Company Dearborn, MI 48121

Donald Nagy and Arnold Prostak General Motors Corporation Milford, MI 48380

Albert Hochhauser Exxon Research and Development Company Linden, NJ 07036

Although emissions from current gasoline-powered motor vehicles have been reduced significantly since the 1960s, these emissions still account for a significant fraction of the hydrocarbons (HC) and nitrogen oxides (NO,) emitted into ambient air. HC and NO, react with sunlight to form ozone, a major component of photochemical smog ( I , 2). Motor vehicles are also a source of carbon monoxide emissions and toxic air pollutants (3).Approaches to reducing vehicle emissions include the use of reformulated fuels, alternative fuels, improved catalysts, modified e n gines, and better electronic engine control strategies. Recent legislation has been e n acted by the federal government and the state of California to require further reduction of vehicle emissions to improve air quality ( 4 ) . In October 1989 the three domestic automobile companies and 14 petroleum companies established a cooperative research program, the Auto/Oil Air Quality Improvement Research Pro gram (AQIRP), The goal of this program is to develop data regarding the potential reduction in total vehicle emissions and improvement in air quality that may result from the use of reformulated gasolines in existing vehicles, as well as the use of methanol fuel (e.g., 85%methanoV15% gasoline) in flexible-fueled (FFV) and 0003-2700/91/0363-1149A/$02.50/0 0 1991 American Chemical Society

variable-fueled (VFV) vehicles. By sharing resources, these organizations believed they would be better able to provide the technical expertise and state-of-the-art facilities to undertake such a complex research program in a short period of time. The specific research objectives of the Phase I program were to test 26 reformulated and two reference gasolines in 20 current (1989) and 14 older (1983-85) vehicles as well as two methanol blends (M10 and M85) and one industry-average fuel in 19 FFV or VFV passenger vehicles (5). These tests involved the collection and analysis of tailpipe exhaust and evaporative emissions during simulated city driving conditions. Detailed chemical speciation data were needed for modeling studies to predict the effect of fuels on air qual-

past 20 years to characterize vehicle none met the strinemissions (7-l2), gent requirements of this program. Analytical approach To satisfy the needs of this research program, analytical techniques must satisfy a number of requirements. They must be able to characterize the C C 12 hydrocarbons and oxygen ated hydrocarbons present in exhaust and evaporative emissions as well as in fuels and fuel blends. In addition, because emissions testing facilities typically used for measurement of regulated vehicle emissions (e.g., hydrocarbons, carbon monoxide, and nitrogen oxides) do not usually have the laboratory personnel or environment found in a research laboratory, the techniques required for this large workload need to be highly

ANALYTICAL APPROACH ity in major urban areas (such as Los Angeles, New York, and Dallas/Fort Worth). Analytical data were needed for more than 8000 samples over a nine-month period. The challenge to the analytical chemist was to develop highly automated and accurate procedures for the speciation of emissions that could be carried out 24 hours a day with a high degree of reliability in vehicle testing facilities. Vehicle emissions originate from the complete and incomplete combustion of fuel, engine oil evaporation, engine oil combustion, and fuel evaporation. As a result, these emissions are composed of hundreds of gas and p a r t i c u l a t e - p h a s e organic com pounds in the part - per - trillion to part-per-million range (3, 6). Although numerous analytical techniques have been developed over the

automated, user friendly, and rugged enough for vehicle testing facilities. The methods used for the emissions measurements are summarized in the box on p. 1150A. Flame ionization detection (FID), nondispersive IR, and chemiluminescence instruments have been used to measure emissions for more than 15 years. These techniques are typically accurate and reproducible to better than 10%for the measurement of emissions from current model vehicles (198991). This program concentrated on the development of GC techniques for C,-C,, hydrocarbons, ethers, and alcohols, and on HPLC techniques for C,-C, aldehydes and ketones. Several factors can influence the accuracy and reproducibility of vehicle emissions measurements. Important variables include those associ-

ANALYTICAL CHEMISTRY, VOL. 63, NO. 23, DECEMBER 1, 1991

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ANALYTICAL APPROACH ated with the test facility (vehicles, drivers, fuel consumption, dynamom eters, environmental conditions, and contaminants in the background dilution air) as well as those associated with the analytical technique (losses/ reactions in the sampling system; instrument noise, detection limits, selectivity, and response time; and accuracy of reference materials and species identification), One of the objectives of the analytical development program was to perform studies that could be used to determine how these various sources of variability can influence the accuracy and precision of the speciation measurements. The testing program was designed and sized in terms of

the number of vehicles, number of tests, and the fuel matrix so that valid statistical relationships could be derived between the composition of the fuel and emissions. It was necessary early in the program to establish requirements in terms of precision a n d accuracy. I n addition, computer software was needed that could control the instrumentation, automatically identify and quantify chemical species, and compile data sets for the modeling studies. To produce reliable atmospheric modeling results, it was determined that individual species needed t o be measured at the 0.05 ppm C levelapproximately 1.0 mg/mi tailpipe Federal Test Procedure (FTP) com-

ds used for emissions r-surements Analvte

Methc-l

-

Total hy bons Carbon monoxide/carbon ai Methane Total nitrogen oxides C,-C,, hydrocarbons and ethecs

ronatsp ;C ;hem iluminesce ;C

posite emission rate for C, specieswith better than +20% RSD for repetitive tests. The identified species should account for more than 85% of the total hydrocarbon mass emitted, and no more than 5% of the components at concentrations 2 0.05 ppm should be misidentified.

Emission sampling The old adage in analytical chemistry that “the development of proper sampling methodologies is at least 50% of the t a s k is particularly true for vehicle emissions measurements because the laboratory tests must simulate real-world conditions as closely as possible. Three different testing protocols were necessary to account for all emissions. Figure 1 depicts the sampling techniques used for tailpipe, evaporative, and evaporative running loss emissions. Although one facility could be designed to accommodate all three types of tests as shown in the figure, three separate facilities were used in these studies to simplify the collection of each sample type. Tailpipe emissions. The most common vehicle exhaust emission test driving schedule used i n the United States is the Environmental Protection Agency (EPA) Urban Dy-

r

Figure 1. Testing facility used for the sampling and analysis of exhaust, running loss, and evaporative emissioi.,. 1150 A


namometer Driving Schedule (UDDS), which is part of the FTP (13).This FTP driving schedule has three phases and was used in all of the AQIRP studies. The dynamometer shown in Figure 1is used to simulate the load a vehicle would encounter under actual road driving conditions. The tailpipe emission samples were diluted about 15:l or 30:l with filtered, humiditycontrolled air for gasoline or methanol blends, respectively. Humiditycontrolled laboratory air was used to prevent condensation of water and to allow cooling. The diluted samples were collected in three Tedlar bags during the corresponding cold start, stabilized, and hot-start phases of the 31.3-min FTP schedule. Some chemical species may be lost as a result of surface adsorption (e.g., formaldehyde) and reactions of labile species (e.g., 1,3-butadiene). Contamination may enter from surfaces (e.g., silicones), and background air (e.g., fuel). Prevention of water condensation becomes more of a problem when methanol/gasoline mixtures are used, because methanol combustion produces twice as much water as that of gasoline. Water condensation was minimized by increased dilution of the exhaust sample and/or dehumidification of the diluent air. To minimize any losses in the Tedlar bags, the samples were normally analyzed within 4 h following collection. Timelstability studies demonstrated that there was negligible loss of C,-C,, species during the first 4 h of collection. Even highly polar organic species such as methanol and formaldehyde showed good recovery (better than 90%) after storage in a Tedlar bag for up to 4 h (14). Evaporative emissions. Volatile hydrocarbons can also evaporate from various noncombustion sources such as the fuel tank cap, fuel tank, fuel lines, carbon canister, and various fuel system seals. To measure such evaporative emissions, the vehicle was placed in an environmentally controlled chamber for prescribed pe riods of time and under specific environmental conditions, and the gas tank was heated as part of the testing protocol. “Grab” samples were taken at the start and end of the test using impingers or Tedlar bags. Running loss emissions. Run ning loss emissions represent the evaporative loss of fuel during simulated driving conditions. The temperature of the fuel tank was controlled to simulate fuel tank temperature profiles obtained on the road, and a

point source method was developed for the measurement of vehicle running loss mass emissions. The technique required the design and fabrication of both the equipment to heat and cool the fuel system on the vehicle (to match the road temperature and pressure profiles for fuel in the tank) and the sample collection system for collecting vapors from specific “points” such as the charcoal canister fresh air vent, the fuel tank safety relief valve, and the fuel filler cap. The running loss test required that a test site be modified to enable the vehicle to be run on a chassis dynamometer at a test cell temperature of 95 OF. Extensive training of laboratory personnel was required to match the road temperature profiles for the fuel system in the test cell environment on a precise and repeatable basis. Operational, calibration, and quality assurance procedures were also developed, because they were not available as part of the normal emissions certification testing protocol. Speciation of emissions As shown in Figure 2, a variety of analytical techniques were developed for speciation of emissions. Most of the developmental work focused on the speciation of C,-C,, hydrocarbons and ethers, C,-C, aldehydes

and ketones, methanol, and ethanol. Speciation of hydrocarbons and ethers. Most of the hydrocarbon mass emitted from gasoline -fueled vehicles consists of C,-C,, hydrocarbons. When oxygen-containing fuel components, such as methyl tertbutyl ether (MTBE), ethyl tert-butyl ether (ETBE), or alcohols are used, the oxidation products of these components as well as the components themselves may also be present in emissions. Laboratory studies were undertaken to determine the detailed composition of the 26 reformulated and two reference gasolines. These fuels were found to contain about 200-300 different hydrocarbon species that were p r e s e n t at concentrations > 0.01 wt %. A multiple-column GC approach has been used by the EPA, the California Air Resources Board (CARB), and other investigators (7-12) to adequately resolve these complex samples. However, a multiple -column approach was considered unacceptable for the Phase I program because several gas chromatographs would be required for the analysis of each sample, calibration and quality assurance procedures would be difficult to carry out, and data merging would be complex. I n addition, a multitechnique approach would be too time-consuming to allow the

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Figure 2. Sample sources and analytical procedures for speciation of emissions. ANALYTICAL CHEMISTRY, VOL. 63, NO. 23, DECEMBER 1, 1991

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ANALYTICAL APPROACH analysis of 8000 samples in nine months. Although G C N S was considered a s a possible single-analysis a p proach, such a procedure would be costly and difficult to incorporate on a routine basis in vehicle emissions testing laboratories. In addition, a quantitative procedure using GC/MS would have required that a library of response factors be developed for each component, and daily calibration and quality control procedures would have been more complex. An optimized single - column GC analysis technique was therefore developed. I t was necessary to carefully assess the trade-offs between compound selectivity, detection limits, accuracy, precision, and the effect of these parameters on the accuracy of the modeling calculations. The analytical development studies focused on the GC and G U M S characterization of various test fuels and emissions to help establish an understanding of the relationship between fuel composition and tailpipe emissions. Exhaust emissions from vehicles, single -cylinder engines, and flame pulsators were used to help generate samples in this effort (15). A GC reference library that consisted of 141 compounds (including paraffins, olefins, alcohols, aldehydes, ethers, and aromatic hydrocarbons) was established over a period of about six months. Validation studies conducted before the initiation of the Phase I program demonstrated that these 141 compounds accounted for - 95% of the hydrocarbon mass in exhaust emissions. A 60-m x 0.32-mm i.d. (1-pm film) DB- 1capillary GC column was found to produce the optimum resolution for this library of compounds. A GC program that used a two-step linear temperature ramp (55-min total analysis time) was devised. All GC systems were equipped with split/ splitless injection and a n automated gas sampling valve with a 2.0-mL sample loop maintained at 110 "C. The split was 51, which resulted in a sample injection volume of 0.4 mL. This single - column gas chromato graph yielded good separations for C,-C, hydrocarbon species, which have presented co-elution problems with some other columns and temperature programs; near - baseline resolution of the C, hydrocarbons was observed. It was not expected that all significant species would be resolved in the single-column GC analysis of these chemically complex samples. There 1152 A

were three important unresolved coeluting pairs: benzene/l -methylcyclopentene, toluene/2,3,3- trimethyl pentane, and m-xylene/#-xylene. Further studies were required to de termine the importance of these coelutions on the atmospheric modeling results . GC/MS characterization was undertaken to determine the benzene/ 1-methylcyclopentene ratio in the exhaust and evaporative emission samples (16).Because 1-methylcyclopentene is much easier to combust and catalytically oxidize than benzene, only trace quantities of 1-methylcyclopentene were found in the exhaust emissions, compared with benzene. I n addition, benzene is formed in the engine via pyrosynthetic and free radical processes. Therefore, the contribution of 1-methylcyclopentene to the benzene peak was considered to be negligible in the tailpipe emission samples. The benzene/methylcyclopentene ratios in the evaporative (vapor phase) samples were found to be similar to their relative concentrations in the fuels, which is consistent with the similar boiling points of these species. The toluene concentration was cor rected by measuring the 2,3,4-trimethylpentane (234TMP) concentration and applying a correction factor. The he1 composition data showed that the 2,3,3-trimethylpentane (233TMP) concentration was close to that of 234TMP. Because 233TMP a n d 234TMP have nearly equivalent chemical reactivities, it was assumed that the ratio of 233TMP to 234TMP would remain relatively constant in the emission samples. Thus the tolu-

and ethanol


ene concentration was determined by measuring the toluene/233TMP and 234TMP peaks and applying the appropriate corrections. The relative concentration of the xylene isomers was nearly constant in the 26 reformulated gasolines (m-xylene/#-xylene: 2.4/1.0). This ratio was also found to be constant in the tailpipe and evaporative emission samples. One problem encountered in this development program was the short age of suitable computer hardware and software that could be used to effectively identify and quantify the 141 hydrocarbon species with a high degree of reliability and accuracy. A Hewlett-Packard Model 5890 gas chromatograph with a dedicated computer system represented a good starting point for further development. Additional software was developed to facilitate calibration, species identification, quantitation, and data reporting. Species identification was based on the comparison of retention times and retention index (RI) values. RI was calculated as RI = 100 n + 100 [(trcz., - tr(n))/(tr(n + 1) - tr(n,)l where t,, is the retention time of unknown species X , trc,, is the retention time of the n-alkane eluting prior to X, tr(lz+ is the retention time of the n-alkane eluting immediately after X, and n is the carbon number of the n-alkane with retention time trcn,. The qualitative accuracy of this procedure was confirmed with authentic standards and by GC/MS

.4nalysis of each standa in quadruplicate with control limit of +8% compared with leaelsquares fit Zontrol limits of +lo' at concentrations of 21.€I pg/mL, +25% at 0.06 ' pg/mL, and +50% at 50.06 pgim

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analysis. The detection limit was about 0.03 ppm C (signal-to-noise ratio of 3). Quantitative determinations of hydrocarbon concentrations above 0.05 ppm C were reproducible to better than 20% RSD. Under the t e s t i n g conditions u s e d i n t h e AQIRP, a concentration of 0.05 ppm C is equivalent to an emission rate of approximately 1.0 mg/mi. Speciation of aldehydes, ketones, and alcohols. Oxygenated hydrocarbons, such as aldehydes, ketones, and alcohols, require different sampling and analysis procedures than the aliphatic and aromatic hydrocarbons. C ,-C8 aldehydes and ke tone species were sampled in impingers containing a n acetonitrile solution of 2,4- dinitrophenylhydrazine (DNPH) derivatizing reagent, and the 2,4- dinitrophenylhydrazone derivatives were determined using HPLC. Methanol and ethanol were collected in impingers containing distilled water and determined by GCFID on a DB-WAX 30-m megabore capillary column. The 0.03-ppm detection limit was similar to that for the C,-C,, hydrocarbons. Characterization of fuels. As mentioned earlier, detailed speciation of the fuels and fuel feedstocks was necessary for development of the GC library data file. Once the testing program was under way, the fully blended fuels were characterized in detail by the Ford Research and Exxon Research and Engineering laboratories using GC and GC/MS. The composition data, which was in good agreement between the two laboratories, was averaged t o provide the final fuel speciation data set. In

addition, a number of other fuel properties, including total aromatics, total olefins, total saturated hydrocarbons, bromine number, Reid vapor pressure, sulfur content, carbon/ hydrogen ratio, density, and the temperature a t which a certain percentage of fuel is volatilized (Tg0),were measured ( I 7). Quality assurance Several quality assurance procedures were developed to ensure the highest possible reliability of the emissions measurements (see Table I). The GC retention time scale was calibrated daily by analysis of a 21-component gas reference material consisting of C,-C,, n-alkanes, ethylene, acetylene, 2 - methylbutene, 1,3-butadiene, benzene, isooctane, toluene, $-xylene and o-xylene. Although the concentration of each gas reference species was known within 2-4% (95% confidence limits), this mixture was not used as a quantitative reference material. Instead, methane and propane (2% accuracy) were used as quantitative standards. The response factor for all hydrocarbons, except methane, was assumed to be directly proportional to the number of carbons, as verified in previous studies (7).Peak areas were used for quantitation of the hydrocarbons, and the FID response was nearly linear for the C,C,, hydrocarbons within the concentration range expected for this study. Recovery studies. One of the best tests for assessing the validity of an analytical technique is to “spike” a sample with the analytes of interest, carry out the analytical procedure, and determine the recovery of the “spiked” analytes. Various standards

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Figure 3. Computer protocols for the transmission, collection, and processing of emissions data.


were injected into the exhaust or testing enclosure facility to determine the recovery of the sampling and analysis procedures. The recovery of methanol and hydrocarbons (propane) averaged from 93% to 98% for a series of experiments undertaken over several months. It was much more difficult to establish the recovery of formaldehyde because it is very polar and polymerizes easily. Injection of formaldehyde using a permeation tube or aerosolization of formaldehyde in solution gave recoveries averaging - 80%. Development of a new formaldehyde vapor injection system (18) resulted in recoveries that were consistently > 90%. Interlaboratory studies. Several interlaboratory round-robin and correlation studies were undertaken to help validate the analytical techniques. These studies were designed to distinguish differences among a n alytical techniques and variability among test facilities. A sample was prepared by the EPA Research Laboratory in Research Triangle Park, NC, for a hydrocarbon speciation interlaboratory roundrobin study. A small quantity of gasoline was injected into a gas cylinder filled with nitrogen and a low concentration of light hydrocarbon gases, and the tank was transferred among the Ford, GM, and EPA laboratories for analysis. The average hydrocarbon concentration as determined using a conventional total hydrocarbon FID analyzer was found to be 72.9 ppm C. The GC analyses showed that there were 95 components present at concentrations > 0.1 ppm C and that the average hydrocarbon mass accounted for was 71.2 f 1.9 ppm C (98% recovery). The variation in quantitative results among laboratories was dependent on the concentration of t h e species a n d ranged from 4.7% RSD for concentrations > 3.0 ppm C to 23.1% RSD for concentrations < 0.5 ppm C. Another round-robin study was undertaken for the speciation of aldehydes and ketones. Known concentrations of these species were prepared in methanol and analyzed by Ford, GM, and EPA. The agreement between laboratories was excellent; RSDs ranged from 0.17% to 3.69%. Database management. T h e testing program carried out during 1990 produced a very large data set that required development of a computer data strategy to facilitate data analysis. Figure 3 summarizes the computer protocols developed for

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ANALYTICAL APPROACH handling these emission databases. Each analytical instrument has its own data system for control and data acquisition. The data from these systems were fed to site host computers, then to Electronic Data Systems (EDS, a subsidiary of GM), where all the data were compiled into a common format. The data were then transmitted to Systems Applications Incorporated (SAI), where the working data set was converted to common units and put into a format that could be widely distributed and used. SA1 also provided the three - dimensional atmospheric model calculations for determining ozone formation. All data files have been made available to the member companies, EPA, CARB, and other interested parties.


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Analytical results Statistical analysis and atmospheric modeling studies have been under way since the Phase I testing program was completed in February 1991. Overall, the analytical techniques have met or exceeded the program’s requirements. The speciation procedures produced results with a high degree of reliability. The qualitative identifica tion of chemical species was better than 98% accurate above the 0.05 ppm (1.0 mg/mi) exhaust emission level. Although the analytical techniques could speciate u p to 151 chemical components, only about half that number of species was quantified in any one test. Figure 4 shows the distribution of species as a function of carbon number for the paraffins, olefins, aromatics, and oxygenates for 20 1989 vehicles using one of the test fuels. Forty-four paraffins, 20 aromatics, 18 olefins, and 9 oxygenates were quantified in this set of tests. During the one-year period of the Phase I study, a Ford Aerostar and a Chrysler Dynasty were used in correlation studies to determine if there were any differences in analytical results between the GM and Ford testing facilities. These vehicles were transferred between the laboratories on a regular basis during the entire Phase I studies. For several selected hydrocarbons determined by GC, the agreement between the two Iaboratories was excellent, even down to the 0.1-ppm emission level. Seasonal variability was also studied by determining formaldehyde emission during winter (2/904/90), summer (6/90-8/90), and fall (9/90- 11/90) periods a t the Michigan

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emission of this compound during different times of the year. The correlation between the GM and the Ford labs for the Dynasty was within the reproducibility of the technique in each laboratory (f14%) a t the 2.5 mg/mi emission level. As expected, the agreement between the two labs was not as good when the emissions levels approached the detection limit (- 0.5 mg/mi). The instrumental precision of the GC analysis was also compared with the total test system precision for the measurement of individual species. GC instrument precision was determined by repeated injections of reference compounds a t concentrations equivalent to the designated emis sion levels. Total test precision was determined from the speciation of emissions from repetitive vehicle tests using different facilities, vehicles, and instruments, Total test system precision averaged -24%, 22%, 15%, and 14% at the 0.5-1.0, 1-2, 2-10, and 10-40 mg/mi emission levels, respectively, for all vehicles (Figure 5). The GC instrumentation contributed < 25% to the total system variability above the 2 mg/mi level, and -55% to the variability at the 0.5-1.0 mg/mi level. One method used t o assess the quantitative recovery of hydrocar bons was a comparison of the total hydrocarbon emissions a s determined by the GC speciation and total FID hydrocarbon analyzer proce dures. Recoveries below 100% would indicate hydrocarbon losses during sampling, the absence of significant

chemical species in the speciation procedures, or inaccuracies in either the FID or the GC procedures. The recoveries were calculated by sum ming the concentrations of all hydrocarbon and oxygenated species as determined by GC and HPLC and comparing these results with the tot a l hydrocarbon values a s determined by the total hydrocarbon analyzer procedure. For this analysis, the FID values were corrected for unit responses to formaldehyde, methanol, methane, and MTBE. The agreement between these two methods was excellent; recoveries averaged 88.8%for the 1989 vehicles and 98.6% for the 1983-85 vehicles. The 1 5 1 species typically accounted for > 95% of the total mass of emissions. For both the current and the older fleets, the amount of unidentified material was significantly correlated with the T,, volatility level of the test fuel. For the current fleet, regression analysis showed that for fuels with high T,,, the analytical technique identified an average of 4.3% less material than for fuels with low Tgo.For the older fleet, the analytical technique identified 2.3% less material for the high T,, fuels than for the low Tg0fuels. This suggests that future improvements of the technique should include the addition of unidentified species to the GC library in the ClO-Cl2 range. Future studies Phase I1 studies will be continued over the next two years. Such studies will be undertaken to determine the

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Figure 5. C o m p a r i s o n of gas c h r o m a t o g r a p h i n s t r u m e n t p r e c i s i o n with t o t a l t e s t s y s t e m precision.


durability of emission control sys tems using reformulated gasolines. Other alternative fuels (e.g., compressed natural gas) will also be tested. Testing of emissions from advanced systems is scheduled to include low - emission vehicles and im proved FFVs. Other efforts will be undertaken to determine the effect of catalysts on the reduction of individual hydrocarbons as well as the effect of reformulated fuels on specific vehicle components (e.g., oxygen sensors). New and improved analytical techniques will be needed to support the Phase I1 programs. The Phase I GC method is being modified to improve detection limits by a factor of 10. This increased sensitivity is needed to measure the lower levels of emissions produced by advanced techno1ogy vehicles. A procedure is being developed for the simultaneous preand postcatalyst sampling of emissions while a vehicle is operating under cyclic conditions. A method is also being developed for the collec tion and analysis of particle emissions from reformulated and alternate-fueled vehicles. The success of this collaborative effort was the result of valuable input from many scientists and engineers from supporting organizations, regulatory agencies, and other firms. Special thanks are given to R. Bisaro, R. Brown, S. Cadle, E. Chladek, D. Chock, R. Gorse, C. Kizlauskas, W. Kreucher, F. Lipari, J. Loo, J. McLeod, R. Muntz, M. Salata, J. Richert, A. Schlenker, W. Siegl, and S. Swarin from the auto industry; C. Burton, W. Clark, F. DiSanzo, H. Doherty, M. Levon, K. Hoekman, G. Musser, R. Pauls, L. Rapp, R. Reuter, and A. Schubert from the oil industry; P. Rieger and J. Shikiya from CARB; K Knapp, J. Sigsby, S. Tejada, and F. Black from EPA, Research Triangle Park; A. Lloyd from the South Coast Air Quality Management District; W. Crowley, R. Denyszyn, and S. Miller of Scott Specialty Gases; P. Shore of Ricardo Consulting Engineers; L. S m i t h a n d M. Warner-Selph of Southwest Research Institute; and J. Pitts of Air Pollution Associates. In,addition, the authors appreciate the valuable comments on this manuscript from J. Benson, D. Brooks, V. Burns, W. Koehl, D. Lawrence, D. Meyer, and R. Pahl.

References (1) Finlayson-Pitts, B. J.; Pitts, J. N., Jr. Atmospheric Chemistry: Fundamentals and Experimental Techniques; John Wiley and Sons: New York, 1986. (2) Seinfeld, J. H. Atmospheric Chemistry and Physics of Air Pollution; John Wiley and Sons: New York, 1986. (3) Schuetzle, D.; Daisey, J. M. “Identification of Genotoxic Agents in Complex Mixtures of Air Pollutants” in Genetic Toxicology of Complex Mixtures; Waters, M. D. et al., Eds.; Plenum Press: New York, 1990. (4) “Federal Clean Air Act,” Title 11, Public Law 101-549, amended 1990 and The Low Emissions VehicleKlean Fuels

Program, approved by the California Air Resources Board, September 1990. (5) Burns, V. R.; Benson, J. D.; Hochhauser, A. M.; Koehl, W. J.; Kreucher, W. M.; Reuter, R. M. Presented at the Fuels and Lubricants Meeting of the Society of Automotive Engineers, Toronto, Ontario, Oct. 1991; paper 912320. (6) Schuetzle, D. Health Perspectives J. 1983,47,65-80. (7) Lipari, F. J. Chromatogr. 1990,503,51. (8) Sigsby, J. E.; Tejada, S. B.; Ray, W.; Lang, J. M.; Duncan, J. W. Environ. Sci. Technol. 1987, 21, 466-75. (9) Pelz, N.; Dempster, N. M.; Shore, P. R. J. Chromatogr. Sci. 1990, 28, 23035. (10) Rieger, P.; McMahone, W. Proceedings of the 84th Annual Meeting of the Air and Waste Management Association, Vancouver, British Columbia,June 1991; paper 91-107.3. (11) Warner-Selph, M. A. “Assessment of Unregulated Emissions from Gasoline Oxygenated Blends”; Southwest Research Institute Technical Report, July 1990. (12) Horn, J. C.; Hoekman, S. K. Proceedings of the Air and Waste Management Association Meeting, Anaheim, CA, June 1989; paper 89-9.3. (13) Code of Federal Regulations, No. 40, “Protection of Environment,” Parts 86-99 (July 1, 1989). (14) Andino, J. M.; Butler, J. Environ. Sci. Technol. 1991,25, 1644. (15) Kaiser, E. W.; Siegl, W. 0.; Henig, Y. I.; Anderson, R. W.; Trinker, F. H. Environ. Sci. Technol., in press. (16) Rasmussen, R. A.; Schuetzle, D.; Siegl, W. O., unpublished work. (17) Pahl, R. H.; McNally, M. J. Presented at the Fuels and Lubricants Meeting of the Society of Automotive Engineers, Tulsa, OK, Oct. 1990; paper 902098. (18) Schlenker, A. Chrysler Proving Ground, unpublished work.

Laboratory at Ford, received a Ph.D. in physical analytical chemistry f r o m Brigham Young University in 1977 and worked as a postdoctoral research fellow associate at Indiana University before joining Ford. His research interests include development of analytical methods for complex environmental mixtures and vehicle emissions.

Donald Nagy (left), manager of the test technologygroup at the General Motors Vehicle Emission Laboratory, received a B.S.E. degree in electrical engineering in 1973 and an M.S.E. degree in electrical engineering in 1975 from the University of Michigan. He spent eight years as a project engineer deskning large-scale automated vehicle emission test instrumentation.Prior to joining GM in 1976, he designed and developed space shuttle computer and electronics systemsfor the aerospace industry. Arnold Prostak (right), project engineer at the General Motors Vehicle Emission Laboratory, received a B.S. degree from the College of William and Mary in 1950; an M.A. degree from the Johns Hopkins Universityin 1955; and an M. S. degree in physics in 1960 and a Ph.D. in analytical chemistry in 1969 from the University of Michigan. He is primarily involved in developing instrumentation for measuring automotive emissions.

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Dennis Schuetzle (left), manager of the Analytical Sciences Laboratory at Ford Motor Company, received his B.S. degree from California State University (San Jose) in 1965. He received a Master’s degree from Stanford and the University of California-Berkeley while working at the Stanford Research Institute in 1968 and an interdisciplinary Ph.D. in analytical chemistry and environmental engineering from the University of Washington in 1972. He has edited three books, published more than 80 papers, and given more than 150 presentations on analytical and environmental chemistry. Trescott E. Jensen (right), principal research scientist in the Analytical Sciences

Albert Hochhauser, a regulatory and environmental afairs adviser in the Products Research Division of Exxon Research and Engineering Company, received a B.E. degree fiom Cooper Union in 1969, an M.E. degreefiom New York Universityin 1971, and a Ph.D. in chemical engineeringfiom Camegie-Mellon Universityin 1974. He is chairman of the Data Analysis and Report Writing Subcommittee of the Auto/Oil Air Quality Improvement Research Program. His current research focuses on gasoline properties and automotive emissions.


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Analytical chemistry and vehicle emissions - American Chemical Society

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