(PAH) and Carbon Monoxide Inside a Car and a Subway-Train H. Fromme,' A

Home , Ethylbenzene

Aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAH) and carbon monoxide inside a car and a subway-train H. Fromme,' A. Oddoy," T. Lahrz,* M. Pilot/

^Institute of Environmental Analysis and Human Toxicology Invalidenstr. 60, D-10557 Berlin, Germany

E-Mail: [email protected]

^Berlin Senat Department for Health and Social Services

Abstract

Significant concentrations of volatile organic compounds can be present in the interior of vehicles due to emissions from materials being part of the interior fittings and to combustion and evaporation emissions of the fuel. Two times in 1995 and 1996 carbon monoxide (CO), carbon dioxide (CO:), aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAH), diesel motor emission (estimated as elementary carbon) were determined in the inside of a car (a two year old VW - Golf with a three-way catalyst) and in a subway-train. On each sampling day (in total 16 daily measurements in the car and 16 in the subway) the substances were determined in the breathing zone of the passengers from 7 a.m. to 4 p.m. under different meteorologic conditions (winter- and summertime). The car route followed the subway from the western borough of Spandau to the south-east borough of Neukolln, there and back. This sampling represented a realistic exposure model for driving in a high traffic and polluted area The electric subway-train (also two years in use) connected the same parts of Berlin ( 31 km underground)

At present only the results of the aromatic hydrocarbons, PAH (partial) and carbon monoxide can be presented in this paper. The mean values obtained during the two measurement periods inside the car were 22/22 ng/nf (maximum 26/35 ng/nv*) for benzene, 69/90 ng/nf for toluene, 38/69 ug/nf for m-,p-xylene, 15/25 ng/nf for o-xylene. 14/23 ug/nf for ethylbenzene and 1.0/3.2 ng/nf for benzo(a)pyrene. The mean values obtained in the subway were 5.4/7.4 ug/nv* (maximum 7/16 ug/nf) for benzene, 33/31 ng/nf for toluene, 15/12 ng/nf for m-,p-xylene, 5.4/4.7 ng/nf for o-xylene, 5.5/4.4 ng/nf for ethylbenzene and 0.7/4.0 ng/nf for benzo(a)pyrene A comparison between subway and car shows significantly lower concentrations of the aromatic hydrocarbons and higher concentrations of PAH in the subway train. In wintertime

728 Air Pollution Modelling, Monitoring and Management the concentrations of benzo(a)pyrene are three to four times higher than in summer and followed the changing of the ambient air concentrations. Our results -in agreement with other studies- demonstrate that car occupants rather than subway passengers were exposed to motor vehicle exhaust and evaporative emissions. An overall risk assessment for benzene shows that - even under the conditions of only a one-hour car ride per day - this exposure represents nearly 30% of the total benzene risk.

The mean levels of CO in the car were 6.1 + 3.9 ppm (summer) and 6.9 ± 7.4 ppm (winter) respectively, with peak concentrations of 70 ppm In the subway the values were 2.1 ±0.4 ppm (summer) and 1.9 ± 1.9 ppm (winter). In the car it cannot totally be excluded that critical COHb-levels (2.5%, for patients with coronary heart disease) will be exceeded.

1 Introduction

In the last years - especially after the break down of the Berlin wall - there have been an increase of traffic and density of motor vehicles in the city. Simultaneous air pollution problems associated with this tendency become more important. Many persons, e.g. commuters, spend a lot of time inside cars and/or subways and are exposed against volatile organic compounds and other emissions of motor vehicles. Therefore the main source of body burden and also for the carcinogenic risk of a city population might be using cars.

2 Material and methods

The sampling was carried out twice from August 21 to September 11, 1995 (summer period) and November 29 to December 19, 1996 (winter period). Carbon monoxide (CO), aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAH) were measured in the inside of a car (a two year old VW- Golf, 55kW, with a three-way catalyst) and in a subway-train. On each sampling day the substances were determined in the breathing zone of the passengers from 7 a.m. to 4 p.m. under different meteorologic conditions. The car was not equipped with a filter or air condition system, ventilation and heating were handled by the car driver.

The car route followed the subway from the western borough of Spandau to the south-east borough of Neukolln, there and back. This sampling represented a realistic exposure model for driving in a high traffic and polluted area The electric subway-train (also two years in use) connected the same parts of Berlin (31 km underground).

Air samples were collected on NIOSH®-tubes with personal air sampler (GIL- AIR-ex with constant flow module, Strohlein®) over the period of 8,5h with 0.3 1/min. The volatile aromatic hydrocarbons are desorbed from the charcoal in a sealed screw cap vial (4 ml) with 2 ml carbon-disulfide (CS%, aromatic-free,

Promochem) by shaking for 30 min Extracts were analysed by GC-FID (HP-5890, series II, Autosampler HP 7673, cold injection, CIS 3, Gerstel). GC-parameters were as follows: splitless injection, dual column GC with dual FID - detection. Capillary column: CPSIL

Air Pollution Modelling, Monitoring and Management 729

5 CB-MS (Chrompack, 60m, 0,32mm i.d., 1,0 pm film) and RTX - volatiles (Restek, 60m, 0,32mm id., 1,5 ^m film), column head pressure: lOpsi, temperature program: 35°C/2min. isothermal, rate: 9°C/min. - 125°C/5min. isothermal, 5°C/min. - 260°C. Evaluation of data by HP Chemstation with HP

3365 series II, quantification by external standards and 4 level calibration, calculation of air-concentrations by diffusion coefficients and sampling time (as described by Fa. Drager). Concerning quality assurance in particular the following program was carried out: check of desorption efficiency of aromatic compounds, comparison of results with different methods (columns with different polarity) and external laboratory, check of €82 and diffusive samplers (aromatic-free, other contaminants). Standardruns before, in between and after each samplesequence with concentrations of 0.1 - 0.3 -1.2 - 12 jig/ml CS] corresponding to air concentrations between 3 and 370 ng/nf. Standard-deviation was around 5% for the whole range of concentrations, limit of detection was 1 ^ig/iri* for each compound

PAH - sampling with dust (<10^m) by Gravikon PM 4 (Strohlein) on glass fiber filters (Macherey & Nagel, MN 85-90 BF, sampling time: 8 h, volume: 36 rri>), PAH - desorption from filter by ultrasonic treatment twice with 50 ml cyclohexane, careful removal of solvent and transfer in acetonitrile for HPLC.

HPLC - conditions: pump: HP 1050 (Hewlett Packard), column: MN ET 150/0,25"/3 Nucleosil -5C18 PAH, binary solvent program with H2O/Acetonitrile, detection with fluorimetric detector HP 1046 A with wavelength program. The limit of detection for Benzo(a)pyrene was 20 pg/nf

The detection of carbon monoxide was carried out by using the portable gas monitor Drager® Multiwarn P with electrochemical cells. The electrical signals of the sampler were transmitted to a data logger and analysed with a personal computer.

3 Results

In summer the mean daily temperature inside the car was 28°C (24 - 35°C) and in the subway 29°C (26 - 30°C) and in winter 23°C (18 - 25°C) in the car and 20°C (19 - 21°C). Outside the mean temperature in summer was 19.5 °C and

1.7 °C in the winter period. Only in the summer we find for the car a significant correlation between indoor temperature and the concentration of aromatic hydrocarbons, but there is no correlation between outdoor temperature and these substances.

Table 1 and 2 summarises the concentrations measured during the two sampling periods inside the car and the subway train. The mean levels of CO in the car were 6.1 ± 3.9 ppm (summer) and 6.9 ± 7.4 ppm (winter), respectively. In short periods peak values of 70 ppm were measured. In the subway (tube) the values

730 Air Pollution Modelling, Monitoring and Management

(mean and standard deviation) were 21 ±0.4 ppm (summer) and 1.9 ± 1.9 ppm (winter). A comparison between subway and car shows significantly lower concentrations of the aromatic hydrocarbons (for benzene 3 times lower and for the other aromatic compounds 5 to 6 times lower) and carbon monoxide (3 to 4 times lower) in the subway train.

Mean S.D. Median Max n 1995 1996 1995 1996 1995 1996 1995 1996 1995 1996 Benzene 21.5 21.6 2.3 7.1 20.9 20.6 26.3 35.0 8 8 Toluene 69.4 90.2 8.4 38.2 66.5 881 83.1 146 8 8 m-,p Xylene 376 68.9 4.2 272 36.0 676 44.9 103 8 8 o- Xylene 14.0 245 1.7 8.6 14.4 240 18.0 35.8 8 8 Ethylbenzene 116 22.8 1.5 8.7 13.0 22.4 16.2 34.4 8 8

CO 6.1 7.0 3.9 7.4 6.0 5.0 310 70.0 432 380

Table 1: Summary statistics for aromatic hydrocarbons (;ig/nf) and CO (ppm) inside the car (Mean = arithmetic mean; S.D. = standard deviation; Max = maximum)

Mean S.D. Median Max n [1995 1996 1995 1996 1995 1996 1995 1996 1995 1996 Benzene 5.4 7.4 1.3 1.9 5.4 7.9 7.4 10.3 8 8

Toluene 329 30.7 7.3 5.2 329 29.7 46.5 39.4 8 8 m-,p Xylene 15.0 12.0 5.0 2.4 14.0 11.4 24.4 15.3 8 8 o- Xylene 5.4 4.7 Li- 4 1.0 5.2 4.3 7.9 6.0 8 8 Ethylbenzene 5.5 4.4 2.1 5.1 4.1 9.5 5.5 8 8 L_l-0 CO 2.1 1.9 0.4 1.9 2.0 2.0 5.0 12.0 424 400

Table 2: Summary statistics for aromatic hydrocarbons (ng/rn^) and CO (ppm) inside the subway-train (Mean = arithmetic mean, S.D. = standard deviation; Max = maximum).

Figure 1 shows the mean concentrations of benzene for the eight sampling days of the two study periods.

Air Pollution Modelling, Monitoring and Management 731

summer 1995 winter 1996

Figure 1: Mean concentrations of benzene in the subway train and in the car

Table 3 summarises the PAH concentrations measured in the two transportation modes. A comparison between subway and car shows significantly higher

concentrations of these substances in the subway train No satisfactory explanation could be found yet. May be the bad ventilation and the use of diesel engines inside the tunnel system influenced the air concentrations. In wintertime the concentrations of benzo(a)pyrene are three to four times higher than in

summer and followed the changing of the ambient air concentrations.

Mean S.D. Median Max 1995 1996 1995 1996 1995 1996 1995 1996 Benzo(a)- 1.0 3.2 0.6 1.5 08 3.1 2.4 5.7 car pyrene 0.7 4.0 0.2 2.0 0.7 4.2 0.9 7.1 subway train 10.2 28.7 5.6 14.5 7.3 car I-PAH 228 21.7 570 30.2 67.JL 10.6 274 28.6 623 527 117 subway train

Table 3: Summary statistics for benzo(a)pyrene and the sum of PAH (US-EPA)

(ng/nf) inside the car and the subway-train (1995 n = 8, 1996 n = 8, Mean = arithmetic mean; S.D. = standard deviation; Max = maximum).

732 Air Pollution Modelling, Monitoring and Management

4 Discussion

Table 4 summarises the results of different studies for benzene concentrations inside cars. Our results are in agreement with this studies. It can be demonstrated that car occupants rather than subway passengers were exposed to motor vehicle exhaust and evaporative emissions. Stationary measurements outside underestimate the health risk and it is necessary to take into concideration all exposure pathways. An overall risk assessment for benzene shows that - even under the conditions of only an one-hour car ride per day - this exposure represents nearly 30% of the total benzene risk [6]. There is also a good agreement with the study of Chan et al in Boston subway trains. These authors obtained mean concentrations of 6.9 ug/m* for benzene (in Berlin 5.4 and 7.4 ug/m*) and 2.5 times higher concentrations (in Berlin three times higher) inside cars than in subway trains.

Source Year Location Benzene den Tonkelar [4] 1981 L Delft, Netherlands 30- 115 Rudolf [16] ? Frankfurt, Germany 15-40 (car) 10-13 (van) Liuetalfll] 1987788 Los Angeles, U.S. A 42 31 (summer);

50 (winter) Chan et al [2] 1988 Raleigh, U.S.A. 12 Chan et al fl 1989 Boston, U.S.A. 17 Pannwitz [14] 1989 Liibeck, Germany 70-120 Lofgrenet al [12] 1989 Goteborg, Sweden 57 van Wijnen et al 1990 Amsterdam, Netherlands 43-74 (city) [18] 12-25 (suburban) Weiseletal[19] 1991 New Jersey, New York, 18 (city)

U.S.A. 12 (suburban) Ullrich etal[ 17] 1991 Berlin, Germany 16-32 Chan et al [3] 1992 Taipai, Taiwan 173 R6mmeltetal[15] 1993/94 Munchen, Germany 15-32 Jo & Choi [7] 1994 Taegu, Hayang, Korea 25 (city) 14 (suburban) this study 1995/96 Berlin, Germany 22

Table 4: Benzene concentration in the interiors of vehicles (ug/nf).

The results that the carbon monoxide values in the car were 3 to 4 times higher than in the subway are in agreement with the observation from Knoflacher et al in Vienna [9] Carbon monoxide blocks hemoglobin molecules in red blood cells and deviates the oxygen dissociation curve to the left. Both processes disturb the oxygen transport in the blood and in tissues, respectively. The carbon monoxide values found in the air of the car are not as high that critical COHb-

Air Pollution Modelling, Monitoring and Management 733 values in the blood normally can be exceeded. Only if we suppose the ,,worst case" of a combination of long lasting CO peak values with a driver (non smoker) who has simultaneously a severe lung and a severe coronary heart disease a blood fraction of 2,5% COHb (lower limit of attacks of angina pectoris; [5], [8], [13]) could be exceeded.

Concerning Benzo(a)pyrene (BaP) there are only two other studies, where was measured this substance inside vehicles. In busses on a city route concentrations of 2.4 ngBaP/nf [15] and 1.0 - 4.4 ngBaP/nf [10] respectively, were found.

There is a good agreement with our results (1.0 ng/m* in summer, 3.2 \ig/m* in winter).

5 References

[1] Chan, C-C ; Spengler J.D., Ozkaynak, H & Lefkopoulou, M. Commuter

Exposure to VOC's in Boston, Massachusetts, J Air Waste Manage. Assoc., 1991,41, 1594-1600. [2] Chan, C-C ; Ozkaynak, H.; Spengler, ID & Sheldon, L Driver Exposure to Volatile Organic Compounds, CO, Ozone, and NO: under Different

Driving Conditions, Environ.Sci.Techno!., 1991, 25, 964-972. [3] Chan, C-C; Lin, S.-H. & Her, G.-R. Student's Exposure to Volatile Organic Compounds While Commuting by Motorcycle and Bus in Taipei City, J.Air. Waste Manage Assoc, 1993, 43, 1231-1238. [4] den Tonkelaar W AM & Rudolf, W Luftqualitat im Inneren von

Kraftfahrzeugen, Luftqualitat in Innenraumen, eds. Aurand K ; Seifert B.; Wegner J, pp 219-233, Gustav Fischer Verlag, 1982. [5] Dwyer, P.M. & Turino, G.M Carbon monoxide and cardiovascular disease, N.Engl.J.Med., 1989, 321, 1474-1475.

[6] Fromme, H. Gesundheitliche Bedeutung der verkehrsbedingten Benzolbelastung der allgemeinen Bevolkerung, ZblHyg , 1995, 196, 481- 494. [7] Jo, W.-K. & Choi, S.-J. Vehicle occupants' exposure to aromatic volatile

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108-115. [9] Knoflacher, H Schadstoffbelastungen bei verschiedenen Mobilitatsformen: Das Beispiel Wien, Internationales Verkehrswesen 1990, 42, 222-226 [10] Limasset, J-C; Diebold, F. & Hubert, G. Exposition des conducteurs de bus urbains aux polluants de la circulation automobile, The Science of the

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pp 317-320, Proceedings of the 8th World Clean Air Congress, The Hague, The Netherlands, 1989, Elsevier, Amsterdam [15] Rommelt, H.; Zielinski, M. & Fruhmann, G. Staub und Kfz-Abgase in stadtischen Nahverkehrsmitteln, Luftverunreinigung in Innenraumen, ed

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[17] Ullrich, D.; Seifert, B & Nagel, R Concentrations of Volatile Organic Compounds Inside New Cars, in Critical Issues in the Global Environment, International Environmental Management, Volume 7, Proceedings of the 9th World Clean Air Congress, Air & Waste Management Association;

Pittsburgh, Pennsylvania; 1992. [18] van Wijnen, J.H.; Verhoeff, A.P.; Jans, H.W.A. & van Bruggen, M. The exposure of cyclists, car drivers and pedestrians to traffic-related air pollutants, Int Arch Occup Environ Health, 1995, 67, 187-193. [19] Weisel, C.P.; Lawryk, N.J. & Lioy, P.J. Exposure to emissions from

gasoline within automobile cabins, Journal of Exposure Analysis and Environmental Epidemiology, 1992, 2(1), 79-96