PB85-172567 Sampling of Automobile Interiors for Organic Emissions (U.S.) Environmental Protection Agency Research Triangle Park, NC Feb 85 "V I } ------- PB85-172567 Sampling of Automobile Interiors for Organic Emissions (U.S.) Environmental Protection Agency Research Triangle Park, NC Feb 85 V I ntS m ------- PB85-172567 EPA/600/3-85/008 February 1985 SAMPLING OF AUTOMOBILE INTERIORS FOR ORGANIC EMISSIONS hy David Dropkin Emissions Measurement and Characterization Division Atmospheric Sciences Research Laboratory U.S. Environmental Protection Agency Research Triangle Park, North Carolina 27711 ATMOSPHERIC SCIENCES RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S. ENVIRONMENTAL PROTECTION AGENCY RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711 ------- TECHNICAL REPORT DATA (Pitau rrad lmttnitix«t ox tht rrveru btfon complaint) 1. REPORT NO. 3. EPA/600/3-85/008 MR 1 7 2 5 b 7 /AS SAMPLING OF AUTOMOBILE INTERIORS FOR ORGANIC EMISSIONS ft. REPORT DATE February 1985 7. AUTHOR!*) David L. Dropkln •. PERPORMINO ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAMI AND AOORESS Atnwspherlc Sciences Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Research Triangle Park, N.C. 27711 10. prooram IlImCJvV k6. C9YA1C/01-0028 (FY-85) ii. C0NTrtA£T/6HAhV 12. SPONSORING AOENCV NAME ANO AOORCSS Atmospheric Sciences Research Laboratory - RTP, NC Office of Research and Development U.S. Environmental Protection Agency Research Triangle Park, N.C. 27711 In-house 14. SPONSORING AGENCY CODE EPA/600/09 IS. SUPPLEMENTARY NOTES f' 16. ABSTRACT A study was undertaken to determine the concentrations of N-n1trosam1nes (specifically N-n1trosodimethylamine and N-n1trosomorphol1ne), hydrogen cyanide, and other volatile organic compounds emitted from the interiors of new cars. The three cars tested were placed 1n an enclosed shed and heated with infrared tungsten lamps to simulate the temperature rise (heat bu1ld-up) 1n the Interior of the cars as 1f the cars were sitting outdoors on a hot sunny day. The air Inside the car as well as the air inside the shed was sampled during the entire temperature rise of "heat bu1ld-up" cycle (ambient, ambient to 60eC, and 60°C). These air samples were pulled through cartridges containing adsorbents such as Thermosorb (specifically to collect for N-n1trosamines) and Tenax (used to collect volatile organic compounds), as well as pulling the air through implngers and also Into Tedlar bags to analyze for hydrogen cyanide. Low concentrations of N-n1trosodimethylamine and N-n1trosomorpho- Une were measured In the car Interiors during the heating process, but higher concentrations of these same N-nitrosamines were measured outside of the cars. No hydrogen cyanide was detected Inside of or outside the two cars tested for this compound. A significant background (mainly gasoline vapors) was obtained for the measurement of other volatile organic compounds, which prevented any meaningful comparison between the car Interior and shed emissions. This report covers a period from May, 1980 to February, 1981 and work was completed as of February, 1981. 17. KBV WORDS ANO DOCUMENT ANALYSIS ». DESCRIPTORS b.IDENTIFIERS/OPEN ENOEO TERMS e. COSATi Field/Croup 18. DISTRIBUTION STATEMENT RELEASE TO PUBLIC 19. SECURITY CLASS (Tint Rtpottt UNCLASSIFIED 21. NO. Of PACES 29 20. SECURITY CLASS /TIM page I UNCLASSIFIED 22. PRICE tPA£«m 2IJ0-1 (R««. 4->7) "ivioul coition •• OilOlITt ------- NOTICE The information in this docunent has been subject to the United States Environmental Protection Agency's peer and administrative review and has been approved for publication as an EPA docunent. Mention of trade names or ccmercial products does not constitute endorsement or recommendation for use. ii ------- ABSTRACT A study was undertaken to determine the concentrations of N-nltrosamlnes (specifically N-n1trosod1methylam1ne and N-n1trosomorphol1ne), hydrogen cyanide, and other volatile organic compounds emitted from the Interiors of new cars. The three cars tested were placed In an enclosed shed and heated with infrared tungsten lamps to simulate the temperature rise (heat build-up) in the interior of the cars as if the cars were sitting outdoors on a hot sunny day. The air inside the car as well as the air inside the shed was sampled during the entire temperature rise of "heat build-up" cycle (ambient, ambient to 69°C, and 60°C). These air samples wrre pulled through cartridges containing adsorbents such as Thermosorb (specifically to collect for N-nitrosamines) and Tenax (used to collect volatile organic compounds), as well as pulling the air through impingers and also into Tedlar bags to analyze for hydrogen cyanide. Low concentrations of N-nitrosodimethylamine and H-nitrosomorpholine were measured in the car interiors during the heating procesi, but higher concentrations of these same N-n1trosamines were measured outside of the cars. No hydrogen cyanide was detected inside of or outside the two cars tested for this compound. A significant background (mainly gasoline vapors) was obtained for the measurement of other volatile organic compounds, which prevented any meaningful comparison between the car interior and shed emissions. This report covers a period from May, 1980 to February, 1981 and work was completed as of February, 1981. iii ------- CONTENTS Abstract 111 Figures v1 Tables v11 Acknowledgment v111 1. Introduction 1 2. Conclusions 2 3. Recommendations A 4. Experimental Procedures 5 Cars tested 5 Enclosed shed 6 Testing procedure 9 GC/MS parameters 12 5. Results and Discussion 14 References 19 v ------- FIGURE Number Page 1 Shed Mode #EPS 76, Horiba, volume 1600 ft^ 6 2 Placement of infrared heaters 1n evaporative shed .... 7 3 Side window opposite driver's side showing placement of sampling probes 9 vi ------- TABLES Number Page 1 Characteristics of test cars 4 2 Normal test cycle analyses for NDMA and NMOR 13 3 Analyses for NDMA and NMOR after two days of heat build-up 14 vi i ------- ACKNOWLEDGEMENT The author acknowledges the assistance of Mssrs. J. Lang, N. Perry, J. Duncan, R. Snow, J. Falrcloth, and P. Klllough of Northrop Services Inc. for their work in the preparation of the shed and cars and in collection of samples for this study. The author also acknowledges the assistance of Mr. J. Sigsby, Dr. R. Bradow, of the Atmospheric Sciences Research Laboratory for their general technical suggestions and Mr. K. Krost of the Environmental Monitoring Systems Laboratory. vi i i ------- SECTION 1 INTRODUCTION Low concentrations of potentially carcinogenic organic vapors such as vinyl chloride, N-nitrosam1nes, and benzene have previously been Identified 1n the Interiors of many cars driven in this country (1,2,3). The emissions of these vapors have been attributed to the materials and adhesives used in the interiors of cars for seating, dash boards and trims. Many different types of plastics, (4,5) rubber (6), vinyl fabrics and adhesives are used in a diversity of manufacturing processes to reduce the costs of producing new cars and to reduce the weight of these cars (for improved gas mileage). It is, therefore, useful to investigate the potentially carcinogenic interior emissions from these cars. The purpose of this study was to identify and quantitate some of these interior emissions in new model cars, especially N-nitrosamines, hydrogen cyanide (HCN), and other volatile organic compounds. Three cars, a 1980 Buick Skylark, a 1980 Mazda 6LC, and a 1981 Plymouth Horizon, were placed in an enrobed shod and the interior air of these cars as well as the shed air was sampled before, during and after the cars were heated. Each car was heated to 60°C by focusing six tungsten filament heat lamps on the Interior of the car in order to simulate the temperature rise or "heat build-up" inside a car when it is sitting outdoors on a hot sunny day. The use of an enclosed shed allowed for a controlled environment in order to reduce the potential for outdoor air contamination (7,8). 1 ------- SECTION 2 CONCLUSIONS N-n1trosam1nes were detected 1n the Interior air of all the cars while the cars were heated and at steady state (60°C) temperature. The levels of N-n1trosam1nes measured Inside the autos ranged from an average of <0.04 to 3 0.37 ug/m for N-n1trosod1methylam1ne (NOMA) to an average of f 0.06 to 3 3 0.25 ijg/m for N-n1trosomorpholine (NMOR); limits of detection were 0.04 »/g/m 3 for NDMA and 0.06 pg/m for NMOR. The concentrations of these N-n1trosam1nes measured in the shed, however, were on average two times greater than those measured 1n the interior. The cars were subjected to the heating cycle for two days before the usual sampling test cycle was performed (with and without having first purged the Interiors with air from outside the shed) in order to determine 1f an increased amount of these compounds could be produced by "aging" the cars. The N-nitrosam1ne levels measured under these "drastic" conditions were higher 1n most cases. The levels of N-nitrosam1nes measured 1n the shed, however, were usually greater than those measured 1n the Interior. Measurements of N-n1trosamines in the trunk of the Buick Skylark were on average one and one-half to two times the concentration measured in the shed. These values, however, were obtained even when the spare tire was removed, indicating that other possible sources of N-nitrosamines must be present. No HCN was detected 1n either the Interior of the cars tested or in the shed during the entire heating cycle. The results of the thermal desorption-Gas Chromatographic/Masr. Spectrometry (GC/MS) analyses of the tenax cartridges indicated that small quantities of gasoline were still present in the cars even though the gas ------- tanks were removed and the fuel lines emptied. These gasoline vapors and the vapors of laboratory solvents such as methylene chloride and tetrachloroethylene In high concentrations did not permit evaluation of whether other potential carcinogenic or toxic compounds were being emitted from the Interior of the cars tested. 3 ------- SECTION 3 RECOMMENDATIONS Further study of a larger, more statistically significant sample 1s recommended before any conclusions can be made concerning N-nltrosamine emissions In the Interiors of new cars. Instead of purging the shed with air outside the shed, hydrocarbon-free air, nitrogen, or helium should be used as well as removing the carburetor and fuel lines from the cars 1n order to define clearly the other volatile organic emissions. Other potential emissions such as vinyl chloride, aldehydes, and ketones should be measured 1n this controlled environment. 4 ------- SECTION 4 EXPERIMENTAL PROCEDURES CARS TESTED Three cars were tested 1n this study. These cars were chosen for testing based on their availability. Two of the cars were rented from a local car dealer and the third was obtained from a car rental agency. The characteristics of the test cars are listed 1n Table 1. To prepare the cars for testing, the gasoline tanks were removed and the cars were operated until the gasoline supply was exhausted. Table 1. Characteristics of Test Cars S 8B:S388:SS8ISS8BSSS88S88SSS8S888B830SSS88S8SB&8esSBS Country No. of and date miles of Model of manu- speedo- Type of Model Ye5r facture meter Interior Tire Month manu- tested facturer Skylark 1980 4 door sedan USA (3/80) 82.3 Tan vinyl 10/80 Goodrich Mazda 1980 2 door 6LC Japan (4/80) 28.0 Black vinyl 8/80 Bridge- stone Plymouth 1981 Horizon 2 door hatchback USA (10/80) 1574 Red vinyl 12/80 Fire- trim, red cloth seats ------- ENCLOSED SHED The testing and sampling were performed using an enclosed shed (Figure 1), which had been erected for the study of evaporative emissions. The shed is constructed of aluminum walls and floor and has a sheet of Tedlar for the celling. The shed has been constructed so that it is "leak tight." Periodically, the shed 1s checked to insure no leaks have developed by injecting known concentrations of propane and then measuring the total hydrocarbon concentration at one hour intervals for 4 to 5 h using a calibrated total hydrocarbon analyzer. The shed is located in an area of a building that also contains a dynamometer facility and wind tunnel. This building contains many research laboratories that are also involved in programs concerning the collection and identification of air pollutants. There Is no physical separation between the test area and the laboratories in this building. The dynamometer was not in operation and no other cars were observed in the testing area at the time of this study. Tungsten quartz lamps (Fostoria Industries, Inc., Fostoria, Ohio) were used to heat the interiors of the cars. These lamps are the same as those used to dry fresh paint on cars. The heaters consisted of six quartz tungsten tubular infrared lamps contained in a #19 guage steel panel shell finished inside and out with a green baked synthetic enamel. The reflectors were made of a gold porcelain coating. The electrical connections were made using Teflon-insulated, stranded copper wire to the procelain connectors on the lamp housing. The placement of the lamps is indicated 1n Figure 2. The distance from the lamps to the roof of the car was approximately 3 ft. At this distance, it required two hours to heat the interio'S from ambient temperature to 60°C. Four lamps were focused to heat the roofs of the cars. Two other lamps were focused to heat both the roof and the interior, but were placed opposite to 6 ------- AlUMIMUW floor ANO WAllS Figure 1. Shed. Horiba. Inc., model EPS76, volume: 1600 fA 7 ------- Figure 2. Placement of heating lamps in evaporative shed. 8 ------- where samples would be collected. The light intensity of each lamp, and therefore the amount of heat produced, was controlled by Varlacs outside of the shed. A shed was constructed outside the building where the actual testing was to be performed 1n order to determine the expected final interior temperature and the time required to obtain this final temperature for a typical sunny day in the middle of June. The shed consisted of a wood frame covered with Tedlar film that was sealed with Visqueen tape. The average ambient temperature for the three days measured ranged from (10 to 21°C) at 9:00am and from (30 to 32°C) at 11:00am. The vehicle Interior temperatures were measured by a thermobouple positioned in the fronc seat. With all the vehicle windows closed, interior temperatures ranged from 56 to 64°C. In an afternoon test when the ambient temperature ranged from 29 to 31°C, the vehicle interior temperature ranged from 49 to 61N.D.(2)°C. TESTING PROCEDURE The placement of the sampling probes is shown in Figure 3. Thermocouples were also placed at the same locations in which samples were to be collected in order to monitor the temperatures at each particular sampling location. The sampling was performed at three different temperatures. The first sample was collected at ambient temperature, the second was collected during the heat build up and the third was collected one half hour after the temperature in the interior stabilized at 60°C. Some samples were also collected in the trunk of the Skylark with and without the spare tire. The "worst case" test situation was done by performing the "heat build up" cycle with the cars in the shed for two days without sampling and allowing 9 ------- Figure 3. Passenger window showing placement of sample probes. In ------- the cars to remain 1n the shed for the two days. On the third day the air was sampled, with and without having first purged the car Interior or shed air, following the usual "heat build up" procedure. The cartridges used for sampling and analysis of the volatile organic compounds and nltrosamlnes were placed Inside the cars. Preliminary tests had Indicated that at an Interior temperature of 60°C there was no difference between collecting samples In cartridges placed inside the car and collecting samples from the interior through 1/4 in. Teflon tubing with the sampling cartridges placed outside the shed. After ambient temperature sampling was completed, these cartridges were removed from the shed. When the sampling during the "heat build up" was completed, the pumps were shut off for these cartridges. They were removed after the 60°C sampling test had also been completed. The trunk of N.D.(2)the Skylark was sampled with and without the spare tire during this study. Before the testing was initiated, the shed (with no car inside) was heated to 60°C for an entire day and then allowed to cool to ambient overnight. This procedure was repeated for several days. The shed was then flushed each day with room air. The day prior to testing, background samples from the shed (with no car inside) were collected at ambient, ambient to 60°C, and 60°C. A Thermosorb sampling system was used to collect for potential N-n1trosamine emissions as this system has been demonstrated as the method of choice for retaining 100% of any pre-loaded N-n1trosamines (9,10). The Thermsorb cartridges used to collect the air samples were supplied and analyzed by the Thermo Electron Corp. (Waltham, Mass.). Air samples were collected at a flow rate of 1 1/min using calibrated flowmeters. 11 ------- Two completely separate methods were used to measure HCN: one method Involved collecting the air in a Tedlar bag and then analyzing a sample of this bag using a GC coupled to a chemiluminescent detector (11), the other method involved collecting the air sample into an impinger containing 25ml of 0.625N NaOH and analyzing the samples using a colorimetric chemical analysis system (12). The limit of detection for HCN by the GC method 1s 10 ppb and is 25 ppb for the colorimetric method. These limits of detection were determined by Stump (13) when he compared and adapted three different methods (1- GC-chemiluminescent detector system (11), 2- colorimetric method(12), and 3- The use of an optical gas filter correlation spectrometer) to analyze for HCN in automobile exhaust. Tenax cartridges were prepared as described elsewhere(l). The air samples collected in the Tenax cartridges were analyzed using a Nutech Model 320 thermal desorption system coupled to an H.P. Model 5992A gas chromatograph/mass spectrometer (GC/MS) system. The sampling rate for the collection of air through the Tenax cartridge was 300 ml/min, as measured by calibrated flow meters. GC/MS PARAMETERS The GC column was a 25 m by 0.32 1.d. SP 2000 fused silica capillary column (Hewlett Packard). Helium was used as the carrier gas and it was controlled at 3 ml/min using a Tylon flow controller. The GC temperature programming parameters were as follows: Initial temperature, 30°C; initial time, 8.0 mln; program rate, 4°C/min; final temperature, 150°C; and final time, 5.0 min. The mass spectrometer parameters were as follows: scan speed, 690 amu/s; ionizing voltage, 70 eV; and electron multiplier, 2600 V. The Nutech desorption unit parameters were as follows: cartridge desorption 12 ------- temperature, 240°C; cartridge desoprtlon time, 5.0 m1n; helium flow through cartridge, 15 ml/m1n; cold trap temperature, -150°C; and final temperature of that trap, 190°C. ------- SECTION 5 RESULTS AND DISCUSSION The results of the analyses for the N-n1trosam1nes (NOMA and NMOR) are listed in Tables 2 and 3. No NDMA or NMOR was detected in the shed (without the car inside), at ambient, ambient to 60°C, or at 60°C, or in the air surrounding the shed. Also, there was no hydrogen cyanide detected in these background samples. In general, the results indicate the NDMA and NMOR were emitted at low concentrations when the interiors of these cars were heated from ambient to 60°C. In almost all cases, greater quantities of NDMA and NMOR were measured in the shed air than in the cars' Interior during every test cycle. At ambient only NDMA was detected in the interior of the Plymouth Horizon. At 60°C NDMA was detected and measured in all of the car interiors and only in the Mazda was NMOR not detected. The average interior concentration of NDMA and NMOR emitted at 60°C were lower, 0.17 ug/m^ NDMA and 3 3 <0.13 ug/m NMOR, than the levels measured in another study (2), 0.3 ug/m NDMA and 0.67 ug/m3 NMOR. The NDMA emitted from the interior of the Plymouth Horizon increased from 3 trace levels to 0.55 ug/m for the three times the car was heated. No NMOR was detected during this experiment. Only one sample of the interior of the Skylark and Mazda was obtained during the "heat build up" so that no determination could be made of an increase or decrease in NDMA emission over time. The data from the "aging" testing indicates, however, that little if any NDMA was produced during the two times the cars were heated. 14 ------- Table 2. Normal Test Cycle Analyses for NOMA and NMOR Car (condition)0**1 Interior NDMA, (uq/m ) Shed Trunk Interior NMOr!? (uq/m ) Shed Trunk Skylark Ambient temperature* Heat build up 60°C Mazda Ambient temperature Heat build up 60°C N.D.f(2)9 0.37(1) 0.18(3) N.D.(3) tr(l) 0.18(3) 0.18(2) 0.16(1) 0.48(3) tr(3) 0.21(1) 0.40(3) 0.15(2) N.D.(1) 0.54(3) N.R. N.R. N.R. 0.14(2) N.D.(l) 0.25(3) N.D.(3) N.D.(1) N.D.(3) N.D.(2) N.D.(l) 0.42(3) N.D.(3) N.D.(l) tr(3) N.D.(2) N.D.(1) 0.39(3) N.R. N.R. N.R. cn Horizon Ambient temperature Heat build up 60°C 0.16(3) 0.30(3) 0.16(4) N.D.(l) 0.13(1) 0.61(4) N.R. N.R. N.R. N.D.(3) N.D.(3) N.D.(3) N.D.(1) N.D.(3) 0.19(4) N.R. N.R. N.R. :=sacB=s: a b c d e f g h i '"LD = ^U/"1 '"LD = wg/m^ Trunk temperature was 46°C when interior temperature was 60°C Duration of experiments: ambient temperature, one hour; heat build, two hours; 60°C, one hour Car initially equilibrated in shed over weekend; average of one sample obtained with and one sample obtained without purging of car and shed N.D. = not detected Number in parentheses is number of times experiment was run N.R. = no sample collected. 3 T Trace value < 3 x NDMA <0.12 yg/m ; NMOR <0.18 gg/m ------- Table 3. Analyses for NDMA and NMOR After Two Days of Heat Build Up Car (condition)0*^ noma! (uq/m ) NMOR^ (wq/m ) Interior Shed Trunk Interior Shed Trunk Skylark Ambient temperaturee N.D.f (2)9 0.15(2) 0.18(2) N.D.(2) N.D.(2) N.D.(2) Heat build up N.D.(2) 0.19(2) 0.38(2) N.D.(2) N.D.(2) 0.23(2) 60°L 0.33(4) 0.36(2) 0.64(2) 0.34(4) 0.42(2) 0.60(2) Mazda Ambient temperature N.D.(3) N.D.(3) N.D.h N.D.(3) N.D.(3) N.R. Heat build up tr(2)1 0.45(2) N.R. N.D.(2) 0.22(2) N.R. 60°C 0.22(2) 0.51(2) N.R. N.D.(2) 0.32(2) N.R. a b c d e f 9 h 1 Lld =0.04 ug/m Lld "0.06 yg/m3 Trunk temperature was 46°C when Interior temperature was 60°C Duration of experiments: ambient temperature, one hour; heat build, two hours; 60°C, one hour Samples collected with and without spare tire. After two days heat build up, car and shed were not purged N.D. = not detected Number in parentheses Is number of times experiment was run N.R. = no sample collected. Trace value < 3 x NDMA < 0.12 ug/m3; NMOR < 0.18 ug/m3 ------- The Individual N-nltrosamine concentrations measured from the air collected Inside the trunk of the Skylark were greater than the concentrations measured either 1n the Interior of the car or the shed for almost all the tests. The spare tire of the Skylark was removed before the second "aging" test was performed because the spare tires have been suspected as a source of N-n1trosam1nes (6). The levels of N-n1trosam1nes measured after this test, however, were not significantly different than the values obtained when the spare tire was 1n place. The trunk of the Skylark has a physical barrier separating It from the interior; the Plymouth Horizon and Mazda are hatchbacks. The individual levels of N-nitrosam1nes detected 1n the Interior of the Skylark, however, were relatively higher in most of the test cycles than the levels measured in the other two cars. The results of the worst case "aging" tests did not appear different than any of the other tests, Indicating a steady-state emission of N-n1trosam1nes even when the interiors of these cars were heated and were not purged. The HCN collection and analyses were performed on the Skylark and Mazda. No HCN was determined to have been emitted from the Interiors of these two cars. The results indicate that even relatively high (60°C) temperature and "worst case" conditions such as baking out the car for two days without purging the interior did not produce any detectable HCN. The analyses of the shed and car interior air samples collected on Tenax cartridges were performed later 1n the testing program. The cartridges were stored 1n a -20°C freezer until analyzed. The subsequent analyses of many of these cartridges Indicated that the sampling time could have been reduced to approximately one quarter of the actual sampling rate because overloading of the column was observed on the total ion chromatogram. 17 ------- The results of the thermal desoprtlon - 6C/M5 a'.alyses of these Tenax cartridges did Indicate that low quantities of gasoline vapors were still present 1n the cars even though the gas tanks were removed and the fuel lines were emptied. Benzene and toluene were usually the compounds of greatest abundance In the total 1on chromatograms. The areas (total abundance) of the other peaks associated with the components of gasoline Increased as the cars were heated which further Indicates that these vapors were present 1n the cars. The freons and laboratory solvents such as methylene chloride, 1.1,1 trlchloroethylene and carbon tetrachloride were also detected 1n varying concentrations throughout this study. Tetrachloroethylene had the greatest abundance when a background sample of the shed (with no car Inside) was collected and analyzed. This compound was also detected 1n varying concentrations in all the other samples analyzed. 18 ------- REFERENCES 1. U.S. Environmental Protection Agency. Organic Emissions from Automobile Interiors. Interagency Energy Environment Research and Development Program Report, EPA-600/7-77-149, December, 1977. 2. Rounbehler, D.P., J. Reisch, and D.H. Fine. N1trosam1nes 1n New Motor Cars. Fd. Cosmet. Toxicol. 18(2): 147-151, 1980. 3. U.S. Environmental Protection Agency. Sampling of Automobile Interiors for Vinyl Chloride Monomer. EPA Office of Research and Development, I.j- •.<. ial Environmental Research Laboratory, EPA-600/2-76-124, 1976. 4. Canadian Plastics. Outlook for ABS 1n the Automotive Industry. Can. Plastics, October, 1978. p. 40. 5. Plastics World. Whats Down the Line for the Materials Mix in Detroit. Plastics World, November, 1978. pp. 37-52. 6. Fajtn, J.M., G.A. Carson, D.P. Rounbehler, D.H. Fine, V. Relnhold, and K. Belmann. N-Nitrosamines in the Rubber and T1re Industry. Science 205, 1979. 7. Fine, D.K., Rounbehler, D.P. Pelizzari, E.D. Bunch, J.E., Berkeley, R.W., HcGee, J., Bursey, J.T., Sawickl, E., Krost, !(., and BeMarrais, S.A. Dimethyl N1trosam1ne in Urban A1r. Bull. Environ, eentam. Toxicol., 15, 639, 1976. 15 ------- 8. Pitts, J., and R. Metcalf, eds. N-N1troso Compounds In the Environment. In: Advances In Environmental Science and Technology, Vol. 10. John W11ey an Sons, Inc., 1980. 9. Rounbehler, D.P., J.W. Relsch, J.R. Ccombs, and D.H. Fine. N1trosam1ne A1r Sampling Sorbents Compared for Quantitative Collection and Artifact Formation Anal. Chem. 52, 273-276 (1980). 10. Fine, D.H., D.P. Rounbehler, E. Sawicki, and K. Krost. Determination of Dimethyl Nitrosamines in Air and Water by Thermal Energy Analysis: Validation of Analytical Procedures. Environ. Sci. Tehchnol. 11:577-580, 1977. 11. Fontijin, A., A.J. Sabadell, and R.J. Ronco. "Homogeneous Chemiluminescent Measurement of Nitric Oxide with Ozone. Anal. Chem. 42, 575-579 (1976). 12. Eptein, J., Estimation of Microquantities of Cyanide Anal. Chem. 19, 1710174 (1947) 13. Stump., F.D. and W. Ray, Comparison of Some Hydrogen Cyanide Methodologies for Analyzing Automobile Emissions. Unpublished (1978). 20 ------- |