Investigation of volatile organic compounds and phthalates present in the cabin air of used private cars

Environment International 35 (2009) 1188–1195

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Environment International j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / e n v i n t

Investigation of volatile organic compounds and phthalates present in the cabin air of used private cars Otmar Geiss ⁎, Salvatore Tirendi, Josefa Barrero-Moreno, Dimitrios Kotzias European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21027 Ispra (Va), Italy

a r t i c l e

i n f o

Article history: Received 9 June 2009 Accepted 31 July 2009 Available online 3 September 2009 Keywords: VOC Benzene Plasticisers Automobile emissions In-vehicle exposure

a b s t r a c t The presence of selected volatile organic compounds (VOCs) including aromatic, aliphatic compounds and low molecular weight carbonyls, and a target set of phthalates were investigated in the interior of 23 used private cars during the summer and winter. VOC concentrations often exceeded levels typically found in residential indoor air, e.g. benzene concentrations reached values of up to 149.1 µg m− 3. Overall concentrations were 40% higher in summer, with temperatures inside the cars reaching up to 70 °C. The most frequently detected phthalates were di-n-butyl-phthalate and bis-(2-ethylhexyl) phthalate in concentrations ranging from 196 to 3656ngm− 3. © 2009 Elsevier Ltd. All rights reserved.

1. Introduction Volatile organic compounds, i.e. aromatic compounds and alkanes, constitute the biggest portion (Sato, 2004; Fedoruk and Kerger, 2003; Lawryk et al., 1995) of pollutants in the vehicle cabin. Among the VOCs found, benzene is a well-known carcinogen (Group A), while ethylbenzene and styrene are classified as potential carcinogens to humans (Group 2B) by the International Agency for Research on Cancer (IARC) (1987, 2002). Only a few studies have been conducted in private used cars up to now. Past in-vehicle VOC exposure studies primarily focussed on measurements in public transport vehicles and were often carried out in developing countries, where the types of vehicles and fuel are rather different from those in Europe. One report (Air Quality Sciences Inc., 2006) indicates that the levels of airborne chemicals in new cars are significantly higher than recommended for today's indoor environments. Dor et al. (1995) found that the exposure level of monoaromatic hydrocarbons inside a private car is 2–3 times higher than in other means of transportation. It is also pointed out that some of the pollutants inside vehicles come from the exhaust fumes of neighbouring vehicles, penetrating the cabin either naturally or by ventilation. In the USA, Grabbs et al. (2000) screened four new cars after keeping them closed for 1 h to assess the nature of VOCs associated with new vehicle interiors. The initial VOC concentrations of approximately 300–600 µg m− 3 decreased by approximately 90% after three weeks of testing. He found toluene, ethylbenzene, the xylenes and undecane to be present in all cars. Yoshida and ⁎ Corresponding author. E-mail address: [email protected] (O. Geiss). 0160-4120/$ – see front matter © 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.envint.2009.07.016

Matsunaga (2006) reported that internal concentrations of most of the aliphatic hydrocarbons were at the same levels as outdoor concentrations in winter, but in summer, in-car indoor concentrations were higher than the outdoor ones. You et al. (2007) determined the types and quantities of chemicals in new and old vehicles under static conditions. A room-size environmental chamber was utilised to provide stable accurate control of the required environmental conditions (temperature, horizontal and vertical airflow velocity and background VOC concentration). The resulting predominant VOC species were toluene, xylenes, some other aromatic compounds and various C7–C12 alkanes. In a 5-year old vehicle, the concentrations of the top five compounds were: toluene (32.2 µgm− 3), D-limonene (14.4 µgm− 3), butylated hydroxytoluene (BHT) (14.1 µgm− 3), m/p-xylene (10.2 µg m− 3) and n-undecane (9.3 µg m− 3). Leung and Harrison (1999) measured concentrations of benzene, toluene and the xylenes inside of passenger cars while driving along major roads in the city of Birmingham (UK) as well as immediately outside the car and at the roadside. A comparison of concentrations measured in the car with those determined immediately outside showed little difference (I/O-ratio 1.17). The ratio of in-car to roadside concentration was rather higher (I/O-ratio 1.55). Chien (2007) examined inter-brand, intra-brand and intra-model variations in VOC levels inside new cars, also taking into account the temperature inside the vehicle cabin and the trim level of the cars. He reported significant variations in concentrations among the brands and within the models. Individual VOC levels ranged from below the detection limit to thousands of µg m− 3. Chan et al. (2003) measured VOCs in public transportation vehicles in Guangzou (China) and found that commuter choice of public transport greatly affected exposure to VOCs. For example, the mean exposure level of benzene in taxis (33.6 µgm− 3) was the highest, followed by air-conditioned buses (13.5 µgm− 3).

O. Geiss et al. / Environment International 35 (2009) 1188–1195

Semivolatile organic compounds like phthalates are ubiquitous components of the indoor environment (Weschler and Nazaroff, 2008). Some phthalates are manufactured in high volumes and find a wide use in plastic components. Phthalates are not chemically bound in the plastics, but are freely mobile and leachable, so over time, they can be released from soft plastic products into the environment. However, limited information is available on the presence of phthalates inside cabin air. A few past studies focussed on the measurement of phthalates in the air of residential indoor environments. Rudel et al. (2003) sampled indoor air and dust in 120 homes and found concentrations in the air of 52–1100 ngm− 3 dibutyl phthalate (DBP), 59–1000 ngm− 3 di-(2-ethylhexyl) phthalate (DEHP), 31–480 ng m− 3 butylbenzyl phthalate (BBP) and 130–4300 ngm− 3 diethyl phthalate (DEP). Fromme et al. (2004) tested the occurrence of persistent environmental contaminants in the air of 59 apartments and 74 kindergartens in Berlin (Germany). He found concentrations of 1083 ngm− 3 DBP, 191 ng m− 3 DEHP, 37 ng m− 3 BBP, 807 ngm− 3 DEP and 1182 ngm− 3 dimethyl phthalate (DMP). Some attempts are being made to establish indoor air quality guidelines for passenger cars. For instance, the Japan Automobile Manufacturers Association (JAMA) is seeking to introduce a voluntary approach for reducing the concentration levels of volatile organic compounds (VOC) in the cabins of passenger cars. In this context, JAMA has recently drafted the “Vehicle Cabin VOC Testing Methods (for Passenger Cars)” as guidelines for conducting the necessary VOC measurements. Along with this, JAMA will also be launching the “Voluntary Approach to Vehicle Cabin VOC Reduction”—methods designed to satisfy the interior concentration level guideline figures set by the Ministry of Health, Labour and Welfare (MHLW) for 13 different substances. The approach has been applied to new models of passenger cars marketed since 2007. Similarly, the Chinese government decided to introduce a vehicle cabin VOC regulation in July 2007, including trucks and buses. In Europe, there is a growing awareness of cabin VOC emissions and several German Original Equipment Manufacturers (OEM) have set themselves VOC targets based on VDA (Verband der Automobilindustrie) test methods. The German TüV (TüV-Rheinland) awards the “Allergy Tested Interior” seal for car interior materials with very low emissions. Furthermore, the ISO TC 146 SC6 on Indoor Air Quality is developing a new measurement method for the determination of volatile organic compounds in car interiors (ISO/WD 12219-1 Indoor Air—Road vehicles —Part 1: Whole vehicle test chamber—Specification and method for the determination of volatile organic compounds in car interiors). The current study was carried out with the intent to determine the concentration of selected volatile chemicals in the interior of used, private cars in the two seasonal extremes of winter and summer. The cabins of twenty-three cars were monitored for 7 days in December and August 2007 by using passive samplers. Additionally, a target set of phthalates was measured by active sampling inside the passenger compartment in winter only. 2. Materials and methods 2.1. Chemicals All chemicals used were of analytical-grade. The mobile phase for the HPLC determination of carbonyl compounds from passive sampling was obtained using water from a Millipore Milli-Q system (Millipore Corporate Headquarters, 290 Concord Rd. Billerica, MA 01821, USA) and acetonitrile (Carlo Erba, 412392). The internal standard for the gas chromatographic determination of VOC was 2Fluorotoluene (Fluka, 47520). Extractions of the activated charcoal sorbent tubes were performed with carbon disulfide (reagent-plus, low benzene, Aldrich, 342270). The single compounds used for the preparation of the standard for the determination of VOC with GC/ FID were: benzene (Riedel-de Haen, 32212), n-heptane (Riedel-de Haen, 46164), methylcyclohexane (Riedel-de Haen, 46171), toluene

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(Fluka, 89680), n-octane (Fluka, 74820), ethylbenzene (Fluka, 03079), m-xylene (Riedel-de Haen, 46194), p-xylene (Fluka, 95680), styrene (Fluka, 85959), o-xylene (Fluka, 956620), α-pinene (Fluka, 80606), n-decane (Fluka, 30540), pseudocumene (Fluka, 82540), D-limonene (Fluka, 62118), n-undecane (Fluka, 94000), n-dodecane (Fluka, 44010). The carbonyl derivatives used for the HPLC determination were formaldehyde-DNPH (Supelco, 44-2597), acetaldehyde-DNPH (Supelco, 44-2434), acetone-DNPH (Supelco, 44-2436), propanal-DNPH (Supelco, 44-2708) and hexanal-DNPH (Supelco, 44-2614). The EPA phthalate ester mixture (48805-U, Supelco) containing dimethyl phthalate, diethyl phthalate, dibutyl phthalate, butyl benzyl phthalate, di-(2-ethylhexyl) phthalate and di-n-octyl phthalate was used for quantification of phthalates with GC/FID. The internal standard used for the determination of phthalates was 1-phenyldodecane (Fluka, 44178). 2.2. Vehicles under study The owners of the vehicles under investigation were colleagues who volunteered to take part in this study. This approach led to a set of cars of different origin and manufacturing year. Table 1 lists the general characteristics of the vehicles without reporting the car manufacturer. The table contains additional information on driver habits that could influence the chemical levels measured, e.g. smoking, use of deodorizers, open windows and the average daily time the driver spent in the car. All participants lived within a maximum of 20 km from the place of work (Ispra, located in the province of Varese, northern Italy) and none of the volunteers lived in a city. 2.3. Temperature and relative humidity measurements The temperature inside the car cabin was measured every 15 min over the whole period of investigation with Escort RH iLog data loggers (Product Code 60D32, Escort, New Lynn, Auckland, New Zealand) installed inside the vehicles. 2.4. Sampling 2.4.1. Volatile organic compounds Two kinds of passive sampling devices were installed in each car for a time period of 7 days (continuous sampling): the cartridge used for unselective adsorbance of volatile organic compounds on activated charcoal (Radiello, cartridge code 130, diffusive body code 120, supporting triangle code 121, Supelco 3050 Spruce Str., St. Louis, Mo, USA) and the selective carbonyl compounds-adsorbing cartridge (Radiello, Code 165, diffusive body code 120-1, supporting triangle code 121, Supelco 3050 Spruce Str., St. Louis, Mo, USA). 2.4.2. Phthalates Phthalates in the cabin air were measured by placing pumps (Zambelli, Model EGO TT, code PF11202, Bareggio (MI), Italy) on the back seat of the vehicles for approximately 16 h, thus trapping about 1 m3 air in the sampling tubes. The average flow was approximately 1 L min− 1. The sampling tubes were OVS-tenax sampling tubes (SKC, CatNo. 226-56) containing a glass fibre filter and two sections of tenax adsorbent separated by a foam plug. The measurements were made during the months of November and December 2007 and were not repeated in summer. 2.5. Sample preparation and analysis 2.5.1. Passive samplers for VOC determination 2.5.1.1. Passive samplers with activated charcoal adsorbent cartridges. Samples were prepared and analysed following the ISO/FDIS 16200-2 method (ISO/FDIS 16200-2, 2000). The gas chromatographic system

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O. Geiss et al. / Environment International 35 (2009) 1188–1195

Table 1 General information on investigated cars. CAR ID

Time in car/day [min]

Smoking in car?

Deodoriser in car?

Window opened while driving? (summer)

Year of manufacture

Cylinder Capacity [L]

Trim level

Overnight parking

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

60 30 15 15 60 50 60 40 100 10 10 20 30 20 45 35 20 20 30 120 10 40 30

No No No No No No No No No No No No No No No No No No No No No Yes No

No No No No Yes No Yes No No No No Yes No Yes No No No No No No Yes Yes Yes

WO AC WO WO WO AC WO WO AC WO AC WO WO AC AC AC AC AC AC WO AC WO WO

1990 2002 2006 2002 1999 2001 2002 2000 2003 1990 1989 2002 1998 2006 2004 2007 2002 2007 2001 2004 2003 2002 1997

1.1 1.8 1.1 2.0 0.9 3.2 2.8 1.6 1.6 2.3 1.4 2.0 1.8 1.6 1.9 1.9 2.2 1.3 2.0 2.0 2.2 1.0 1.9

Textile Textile Textile Textile Textile Textile Leather Textile Textile Textile Textile Textile Leather Textile Leather Textile Textile Textile Textile Textile Textile Textile Textile

Garage Garage Garage Garage Outside Garage Garage Outside Outside Outside Outside Outside Outside Garage Outside Outside Outside Garage Garage Outside Outside Garage Outside

WO: window open. AC: air conditioning running.

used was an Agilent 6890 equipped with a flame ionisation detector. The detection limit for all compounds lies between 0.2 and 0.3 µg m− 3. 2.5.1.2. Passive samplers with 2,4-dinitrophenylhydrazine (DNPH)covered silica cartridges (selective for carbonyl compounds). Samples were prepared and analysed following the ISO/FDIS 16000-4 method (ISO/FDIS 16000-4, 2004). The method was adapted to the needs of our measurements. Acetaldehyde, acetone, propanal and hexanal were determined in addition to formaldehyde. The liquid chromatographic system (HPLC) used consisted of an Agilent Series 1100 system (Agilent Technologies, Inc., Santa Clara, CA), composed of a G1312A binary pump, a G1379A degassing device, a G1329A Autosampler and a G1315B Diode Array Detector set at 360 nm. The chromatographic separation was performed on a Waters Nova-Pak C18, 60 Å, 4 μm (3.9 × 300) mm column (Waters Corp., Milford, MA). The detection limit for all carbonyls lies between 0.3 and 0.4 µg m− 3. 2.5.2. Determination of phthalates in the vehicle cabin The compounds under consideration were dimethyl phthalate, diethyl phthalate, dibutyl phthalate, butyl benzyl phthalate, di(2-ethylhexyl) phthalate and di-n-octyl phthalate.

OSHA (Occupational Safety and Health Administration) method 104 for the determination of phthalates in the air was adapted to the needs of our measurements. In particular, the amount of sampled air was increased. The pumps were placed inside the cars for approximately 16h starting from the late afternoon. At the end of the measurement period, the glass fibre filter, the tenax resin of the front section and the middle foam plug were transferred to a WISP vial. The tenax resin of the back section and the back foam was transferred to another WISP vial. Three millilitres of the desorbing solvent (toluene containing 1.5 mg L− 1 1-phenyldodecane as internal standard) was added and the samples were shaken for 45 min. This extract was then injected in the GC. The gas chromatographic system used was an Agilent 6890 equipped with a flame ionisation detector. The chromatographic parameters were: column, DB-5 (60 m length, 0.25 mm internal diameter, 1 μm film, Code 19091J-236 J&W Scientific, Agilent, Santa Clara, CA, USA); injector/ detector temperature, 270 °C; constant helium flow, 1.5 mL/min; split ratio 1:10; injection volume 2.5 μL; temperature programme: 150 °C for 1 min; Ramp, 15 °C min− 1 up to 325 °C, final temperature, 325 °C for 13 min; total runtime: 25.6min. The absolute detection limit was determined as being 50 ng mL− 1 extraction solution for all compounds. Extracting with 3 mL of extraction solution and sampling a volume of air of approximately 1000 L lead to a detection limit of 150 ngm− 3.

Fig. 1. Temperatures (min/max/average) measured over 7 days inside vehicles during the month of August (left chart) and December (right chart) 2007.

Table 2 Measured VOC concentrations in August 2007. Car ID

Benzene n-Heptane Methylcyclohexane Toluene n-Octane Ethylbenzene m/p-Xylene Styrene o-Xylene alpha-Pinene n-Decane 1,2,4-Trimethyl D-Limonene n-Undecane n-Dodecane Formaldehyde Acetaldehyde Acetone Propanal Hexanal benzene 0.3 35.1 36.1 4.9 3.8 2.4 46.1 3.5 5.1 3.2 4.4 6.9 1.0 5.7 4.9 0.6 2.6 5.3

bDL 6.3 9.7 10.4 3.4 6.1 11.8 2.1 1.9 1.1 1.7 1.9 0.6 1.5 3.7 0.4 0.8 4.0

3.6 558.4 325.3 27.3 21.4 28.0 315.2 16.5 64.3 10.1 68.2 45.8 7.6 47.5 13.2 3.3 15.9 16.9

6.7 1.1 1.3 7.8 25.3

4.4 0.5 0.5 1.3 9.8

27.6 113.4 69.2 88.9 289.6

Avrg 23.6 Min 2.0 Max 149.1 Median 7.9

9.7 0.6 46.1 4.9

3.8 0.4 11.8 2.0

98.8 3.3 558.4 36.9

bDL 12.2 9.4 5.5 2.7 1.1 13.3 0.9 1.8 1.2 1.7 3.2 1.3 3.2 5.5 1.2 1.5

0.3 60.2 35.0 3.5 3.9 4.0 49.1 2.3 7.5 1.9 10.0 4.6 2.2 9.5 1.4 0.6 2.5 1.2

1.0 219.4 132.1 12.7 13.0 15.1 179.3 7.9 28.2 5.1 37.3 16.2 6.9 33.6 5.7 1.8 8.2 4.2

bDL 2.9 1.7 4.6 4.1 0.5 4.3 2.3 bDL 0.5 0.5 0.3 1.8 0.9 5.2 bDL 1.7 0.3

0.4 62.3 39.1 4.4 4.5 5.5 62.0 2.4 9.2 2.0 12.8 6.7 2.5 11.9 2.7 1.1 3.3 1.6

bDL 0.4 1.0 0.5 1.1 5.3 1.0 0.4 0.6 bDL 0.7 0.7 0.4 0.4 bDL bDL bDL bDL

0.4 1.7 2.1 5.4 8.8 6.9 11.0 6.1 0.6 3.5 2.1 1.7 4.9 2.7 5.6 1.0 10.5 1.8

0.3 50.6 32.9 4.7 7.7 5.5 54.6 2.3 6.3 1.4 12.2 3.7 3.2 11.4 2.6 0.7 3.5 1.5

bDL 9.7 0.5 1.7 0.7 39.7 15.9 21.4 1.9 0.5 0.6 1.6 5.4 2.4 1.1 0.8 1.4 2.7

bDL 9.3 1.0 8.0 12.0 1.3 12.7 4.2 1.7 11.2 0 1.4 6.4 2.6 15.3 bDL 47.8 3.6

9.8 16.1 13.7 33.3 57.7 34.4 21.5 13.1 12.3 70.9 14.5 20.7 32.7 17.7 44.2 10.4 192.5 31.7

2.8 5.1

8.3 2.5 2.1 11.8 33.8

11.6 5.1 4.8 42.6 124.4

2.1 2.1 0.4 0.7 0.7

12.4 4.7 2.1 13.1 39.4

1.0 bDL 0.8 0.7 bDL

5.2 7.2 2.5 2.1 4.2

16.3 2.9 2.2 12.2 29.0

2.4 0 1.2 1.9 2.5

4.6 4.3 7.2 1.8 7.6

53.2 53.2 42.5 11.0 49.0

3.9 0.9 13.3 2.7

11.7 0.6 60.2 4.0

41.6 1.8 219.4 12.9

1.7 0 5.2 1.3

13.9 1.1 62.3 5.1

0.7 0 5.3 0.5

4.4 0.6 11.0 3.9

12.2 0.7 54.6 5.1

5.3 0 39.7 1.8

7.5 0 47.8 4.5

38.5 10.4 192.5 32.2

1.3

1.9 19.6 15.9 14.4 17.9 20.8 24.2 14.6 21.5 20.2 16.0 16.8 16.4 19.5 27.1 Not measured 24.3 16.0 43.6 13.6 27.7 34.6 19.6 23.6

0.4 18.2 57.3 15.0 15.3 14.4 13.5 10.9 17.4 21.1 18.0 65.1 13.5 24.0 13.4

1.5 13.5 55.8 22.0 14.2 15.9 16.7 14.0 29.0 27.1 12.6 56.0 9.6 17.1 30.9

0.3 6.2 41.4 8.9 14.5 5.6 7.3 5.0 10.7 11.2 7.4 32.1 8.9 10.7 7.8

0.8 5.7 24.1 13.4 12.2 18.9 13.3 12.2 17.3 7.0 10.9 21.0 23.9 28.8 19.1

13.4 22.7 12.1 18.5 27.7 27.5 10.8 16.2

21.1 11.3 46.2 18.8 19.1 23.3 9.3 20.8

5.3 18.7 3.6 8.5 25.6 10.5 3.8 8.9

15.1 36.0 17.5 9.5 11.0 44.0 8.3 5.5

21.3 13.6 43.6 19.6

21.2 10.8 65.1 16.8

22.9 9.3 56.0 19.0

11.9 3.6 41.4 8.9

17.0 5.5 44.0 14.3

O. Geiss et al. / Environment International 35 (2009) 1188–1195

Outside 1.3 1 149.1 a 89.3 2 8.2 3a a 7.5 4 5 6.7 a 78.7 6 a 3.2 7 8 12.2 9 4.1 10 13.6 11 17.8 12 2.1 13 3.2 a 5.8 14 15 2.0 16 6.1 17 9.7 a 18 a 9.4 19 20 4.6 21 4.2 a 23.5 22 23 57.6

All values given in µg m− 3. a Cars parked in a garage at night.

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Table 3 Measured VOC concentrations in December 2007. Benzene n-Heptane Methylcyclohexane Toluene n-Octane Ethylbenzene m/p-Xylene Styrene o-Xylene alpha-Pinene n-Decane 1,2,4-Trimethyl D-Limonene n-Undecane n-Dodecane Formaldehyde Acetaldehyde Acetone Propanal Hexanal benzene

Outside 1 2a 3a 4a 5 6a 7a 8 9 10 11 12 13 14a 15 16 17 18a 19a 20 21 22a 23 Avrg Min Max Median

4.4 0.7 0.3 90.7 24.6 7.1 67.1 25.7 5.4 10.0 3.0 2.2 6.4 1.5 0.7 6.8 1.5 0.6 15.6 7.6 2.2 11.6 4.4 2.4 7.3 1.7 0.5 Not anymore available 19.5 6.6 3.2 6.4 1.5 0.5 4.3 0.9 0.5 Not anymore available 8.0 2.4 3.1 7.0 1.2 0.8 5.5 1.1 0.6 9.4 2.5 1.3 8.2 1.6 0.8 6.4 1.7 0.8 Not anymore available 6.6 1.3 0.6 44.3 14.3 3.6 50.6 18.4 3.5 19.6 6.2 2.0 4.3 0.9 0.5 90.7 25.7 7.1 8.1 2.1 1.1

All values given in µg m− 3. a Cars parked in a garage at night

7.9 260.1 309.5 21.5 28.9 23.1 45.0 18.3 23.7

0 11.7 9.6 3.3 1.1 1.7 3.1 2.0 1.2

1.2 33.3 39.4 3.1 2.5 2.9 7.2 2.4 2.8

3.8 118.8 155.9 11.1 8.8 10.7 25.2 8.1 10.3

0.2 3.4 1.8 2.5 2.4 0.3 1.0 0.4 0.3

1.4 38.6 46.2 4.5 3.4 4.0 9.2 3.1 3.6

0 0 0 0.6 0.8 1.3 1.1 0.7 0.9

0 14.9 4.4 20.1 9.5 3.6 3.8 2.9 2.6

1.2 40.1 39.6 3.7 5.4 3.6 7.6 2.2 2.6

0 3.2 7.2 2.2 1.4 8.9 8.3 13.1 4.8

0.6 12.8 1.9 3.8 12.4 0.8 3.9 1.1 2.0

3.9 10.6 10.4 12.9 23.3 11.5 18.2 9.7 10.6

1.8 5.1 4.7 4.7 3.9 3.2 6.8 14.7 8.1

1.6 8.2 5.4 7.0 7.8 5.6 5.9 14.0 6.9

3.9 24.2 20.7 22.3 23.3 14.4 14.4 34.3 26.3

0.4 2.1 1.8 3.5 2.6 1.2 1.6 5.5 1.9

0.2 3.3 1.9 2.4 12.5 8.4 2.2 13.3 6.2

48.2 14.5 9.3

2.5 1.3 1.9

7.5 2.4 1.5

27.2 8.7 7.8

0.6 0.2 0.8

10.2 3.7 1.9

0.4 0.6 0.6

1.6 1.4 3.6

8.7 3.6 1.6

1.2 1.2 7.4

1.1 0.6 1.3

9.9 4.3 7.0

2.6 3.2 2.8

7.9 18.1 38.9

15.2 39.7 22.0

1.5 6.0 1.6

2.3 3.6 3.9

18.3 14.6 12.1 24.7 17.9 12.0

4.0 2.0 0.9 1.4 1.5 1.6

2.8 1.8 2.1 3.2 2.7 2.4

10.3 6.2 7.7 10.8 9.2 8.8

2.6 0.3 0.4 0.4 0.5 1.4

4.6 2.4 2.9 4.2 4.3 3.7

0.6 0.6 0.6 0.9 0.8 0.7

3.1 3.0 3.3 2.3 2.9 4.2

4.1 1.9 2.6 3.2 3.4 5.5

1.9 1.6 2.1 2.4 4.4 1.6

2.6 1.7 3.1 1.4 2.2 3.2

11.1 11.9 16.6 9.6 16.2 18.2

9.1 2.9 4.9 5.0 8.9 4.4

8.0 7.2 5.2 8.5 8.0 7.7

30.3 24.6 18.6 27.5 24.3 16.1

2.6 2.3 1.1 4.9 1.5 2.0

7.6 10.9 2.9 5.4 6.0 2.0

15.6 130.0 239.3 64.3 9.3 309.5 22.3

1.1 6.3 4.0 3.1 0.9 11.7 2.0

2.5 20.0 22.4 8.2 1.5 39.4 2.8

8.6 72.1 79.3 30.3 6.2 155.9 10.3

0.3 2.0 0.5 1.1 0.2 3.4 0.6

3.3 23.3 24.2 10.1 1.9 46.2 4.1

0.4 0.9 1.7 0.7 0 1.7 0.7

1.6 3.5 2.5 4.7 1.4 20.1 3.2

2.8 28.6 13.2 9.2 1.6 40.1 3.7

2.2 4.7 9.4 4.5 1.2 13.1 2.8

0.8 2.2 1.9 3.0 0.6 12.8 2.0

5.1 12.4 10.9 12.0 4.3 23.3 11.0

4.7 7.5

7.7 12.1

25.1 26.2

1.6 2.1

5.8 2.3

5.6 2.6 14.7 4.7

10.0 5.2 38.9 7.8

23.7 14.4 39.7 24.2

2.5 1.1 6.0 2.0

5.4 1.9 13.3 3.9

O. Geiss et al. / Environment International 35 (2009) 1188–1195

Car ID

O. Geiss et al. / Environment International 35 (2009) 1188–1195 Table 4 Median concentrations found in private houses in various European cities in the frame of the AIRMEX project (Kotzias et al., 2009) compared to median concentrations measured in this study inside the vehicle cabin. Compound

AIRMEX Project

This study (summer)

This study (winter)

Benzene n-Heptane Methylcyclohexane Toluene n-Octane Ethylbenzene m/p-Xylene o-Xylene a-Pinene n-Decane 1,2,4-trimethylbenzene D-Limonene n-Undecane n-Dodecane Formaldehyde Acetaldehyde Propanal Hexanal

1.9 0.7 0.5 6.5 2.1 1.1 2.8 1.2 6.1 15.6 1.1 9.5 2.3 15.6 19.7 11.2 2.7 24.4

7.9 4.9 2.0 36.9 2.7 4.0 12.9 5.1 0.5 3.9 5.1 1.8 4.5 32.2 19.6 16.8 8.9 14.3

8.1 2.1 1.1 22.3 2.0 2.8 10.3 4.1 0.7 3.2 3.7 2.8 2.0 11.0 4.7 7.8 2.0 3.9

All values given in µg m− 3.

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3. Results and discussion 3.1. Temperature measurements inside vehicles For a better understanding of the temperatures which can be reached inside vehicles, temperature data loggers were installed for a period of 7 days inside nine cars randomly selected among those investigated. Fig. 1 demonstrates that peak temperatures of almost 70 °C are reached when the car is parked in the direct sun in summer. Since no extremes were expected during winter, temperatures were recorded only in the interior of two cars representing different situations (car parked outside overnight and car parked in garage overnight). No significant difference was observed in the temperatures recorded. The high temperatures reached inside the vehicle cabins in summer have an effect on the presence of chemicals in the cabin air due to the increased out-gassing behaviour of low and medium boiling point compounds from materials used in the vehicle cabin. 3.2. Volatile organic compounds Passive sampling devices were placed inside the vehicle cabin over a period of 7 days in August and in December 2007, statistically considered to be the hottest and coldest months of the year in the area where the study was undertaken. Diffusion constants were corrected for temperature. As reference, a pair of passive sampling devices was exposed to ambient air in the parking place where all cars were parked during the daytime. Tables 2 and 3 show the concentrations found during August and December 2007 respectively. The same set of compounds was measured in the AIRMEX Project (Kotzias et al., 2009). This project was carried out with the aim to identify and quantify the principal air contaminants present in public buildings, including schools and kindergartens as

Fig. 2. Percentage variation in concentrations between summer and winter (2007) measurements.

Fig. 3. Comparison concentrations of VOC (except carbonyls)—ratio cabin/outdoor.

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well as private houses located in various European cities and to evaluate the exposure of the occupants to these pollutants. In the comparison of median concentrations found in the AIRMEX Project with the median concentrations measured in this study (Table 4) we found that most concentrations measured inside the cars are higher than those in private houses, with the exception of a-pinene, D-limonene, formaldehyde and hexanal. Commission Directive 2000/69/EC (European Commission, 2000) establishes a limit value, to be met by 2010, of 5 μg m− 3 (annual mean) of benzene in ambient air. The results of this study show that 68% of the concentrations measured inside the cars in August and 95% in December exceed this ambient limit value. Some results were not taken into consideration for statistical evaluations as the concentrations were not representative: the high concentrations found for car ID2 and car ID6 proved (by measuring concentrations in the garage) to depend directly from a concentration of BTEX in the garages where these cars were usually parked. The owner of car ID 22 habitually smoked cigarettes inside the car. 3.2.1. Seasonal variation of VOC concentrations measured inside the vehicle cabin The seasonal variation was calculated by summing the concentrations of all carbonyl compounds (formaldehyde, acetaldehyde, acetone, propanal and hexanal) and summing the concentrations of all the other VOCs of each car and then by comparing the average value (of all cars) of the sums for winter and summer. The outcome is that, in general, concentrations were significantly lower in December: Carbonyl compounds: on average 42% less compared to August All other VOCs: on average 36% less compared to August For a detailed identification of which compounds decreased or increased, the single values of both measurement sets (August and December) were compared directly by applying the following formula

Ratio =

cðcompound; winterÞ × 100: cðcompound; summerÞ

The average increase/decrease for each compound (average for all cars) is shown in Fig. 2. Fig. 2 shows that most of the compounds which increased in concentration in winter are substances that typically form during combustion processes (except D-limonene) and/or emission/evaporation of uncombusted fuel or penetration of roadway air (Chien, 2007). A possible explanation could be that a lower ventilation rate inside the car during the cold period causes BTEX to concentrate inside the vehicle. The compounds are not predominantly released from equipment parts used inside the vehicle. On the other hand, substances listed in the left part of the chart, lying below the zero-line, decreased in concentration in December, possibly due to the lower temperature inside the vehicle and related lower emission-rates. Many substances among those listed are known to be released from parts used inside the vehicle cabin (Chien, 2007). Potential interior sources include upholstery (carpets, seating surfaces, paint and sealants), details (deodorisers, surface treatments) and other sources such as lubricants. 3.2.2. Comparison of indoor/outdoor ratios in winter and summer time By summing concentrations of selected VOCs (benzene, n-heptane, methylcyclohexane, toluene, n-octane, ethylbenzene, xylenes, styrene, α-pinene, D-limonene, n-decane, n-undecane, n-dodecane and 1,2,4-trimethylbenzene) and carbonyl compounds (specifically formaldehyde, acetaldehyde, acetone, propanal and hexanal) and by dividing these sums by the concentration measured outdoors for the same compounds, vehicle cabin/

Table 5 Concentrations of phthalates measured in the air of vehicle cabins [ng m− 3]. ID car

Diethyl phthalate

Di-n-butyl phthalate

Bis(2-ethyl hexyl) phthalate

1 2 3 4 5 6 7 8 12 13 14 16 17 19 20 21 22 23

bDL bDL bDL 203 346 bDL 523 bDL bDL bDL 1400 bDL bDL 633 200 bDL bDL bDL

bDL bDL 435 617 537 bDL bDL 1630 bDL bDL 477 196 bDL bDL 201 bDL 396 bDL

bDL bDL 610 3656 bDL bDL bDL bDL bDL bDL 535 335 405 bDL 2317 bDL bDL bDL

outdoor ratios are obtained. The ratios of the summer and winter measurements are compared in Figs. 3 and 4. The I/O-ratio is always higher in summer than in winter for both carbonyl compounds and other VOCs. In winter, the ratio for carbonyl compounds ranges from 10.6 to 39.7 (median 15.4) and for the other measured VOCs from 1.4 to 68.6 (median 8.8). In summer, the ratios range from 3.7 to 10.4 (median 6.1) for carbonyl compounds and from 2.0 to 28.3 (median 3.1) for the other measured VOCs. The I/O-ratio of carbonyl compounds in both summer and winter is approximately twice that of the other measured VOCs. These results indicate an overall enrichment of chemical substances of both compound families in summer time, probably due to the higher temperatures inside the cars. 3.3. Phthalates measured in the cabin air of vehicles Phthalates were measured in the cabin air of the same vehicles investigated for their VOC concentrations. Table 5 shows the concentrations found. Dimethyl phthalate, butyl benzyl phthalate and di-n-octyl phthalate were detected in none of the cars. These findings are in the same range of concentration as the values found by Fromme et al. (2004) and Rudel et al. (2003).

4. Conclusions In this work the presence of selected volatile organic compounds (VOC) and phthalates in the cabin of used cars was investigated. The results obtained clearly indicate that high concentrations of VOCs are

Fig. 4. Comparison concentrations of carbonyl compounds—ratio cabin/outdoor.

O. Geiss et al. / Environment International 35 (2009) 1188–1195

accumulated in the vehicle cabin. The mean in-vehicle concentration of VOCs often exceeds concentrations typically found in residential indoor air (Kotzias et al., 2009; Geiss et al., 2008 and therein cited literature). The most abundant VOCs are the aromatic compounds (BTX) with benzene concentrations ranging from 2 to 149 µg m− 3, dodecane and low molecular weight carbonyls (e.g. formaldehyde, acetaldehyde, acetone). The most common phthalates measured were diethyl phthalate, di-n-butyl-phthalate and bis-(2-ethylhexyl) phthalate in concentrations similar to other indoor environments. The penetration of outdoor air, emissions from materials present inside the cabin and (possibly) leakages from the fuel distribution system are the main factors responsible for the elevated concentrations of the chemicals measured inside the vehicle cabins. The data presented in this paper clearly show the need to assess long term exposure to air pollutants and the related health risks for drivers and passengers. Acknowledgements Our acknowledgements go to all the volunteers who participated in this study by offering their car and time, namely, Camilla Bernasconi, Paolo Leva, Philippe Hannaert, Giorgia Beldì, Barbara Raffael, Eddo Hoekstra, Stelios Kephalopoulos, Francesca Serra, Athanasios Katsogiannis, Sandro Valzacchi, Diana Rembges, Vaidas Morkunas, MariaGrazia Sacco, Kimmo Koistinen, Alessandro Galluccio, Raffaella Morellini, Claudia Contini, Fabrizio Pariselli and Chema Moreno-Rojas. References Chan LY, Lau WL, Wang XM, Tang JH. Preliminary measurements of aromatic VOCs in public transportation modes in Guangzou, China. Environmental International 2003;29:429–35. Chien YC. Variations in amounts and potential sources of volatile organic chemicals in new cars. Sci Total Environ 2007;382:228–39. Dor F, Moullec YL, Festy B. Exposure of city residents to carbon monoxide and monocyclic aromatic hydrocarbons during commuting trips in the Paris metropolitan area. J Air Waste Manage Assoc 1995;45:103–10. European Commission. Directive 2000/69/EC of the European Parliament and of the Council relating to limit values for benzene and carbon monoxide in ambient air. Official Journal of the European Communities 2000;L313:12–21 13/12/2000.

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