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FACTORS EFFECTING EXPOSURES TO VOCS DURING COMMUTING IN CALIFORNIA
Citation:
Sheldon, L S., A W. Rea, A F. Vette, C. E. Rodes, D. Whitaker, P. Jenkins, S. Hui, AND S. Freun. FACTORS EFFECTING EXPOSURES TO VOCS DURING COMMUTING IN CALIFORNIA. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Description:
On the average, Californian's spend between one and three hours each day commuting. The contribution from in-vehicle exposures to air toxics may be a significant component of total air exposure. Although pollutant concentration data are important for exposure assessments, only limited data exist for passenger vehicles. To address this limitation, a study was conducted to measure concentrations of selected air toxics during commuting. Thirteen volatile organic chemicals (VOCs), including 1,3-butadiene, benzene, and MTBE were measured inside two vehicles during 32 driving trips in the cities of Los Angeles and Sacramento. Two-hour integrated samples were collected concurrently inside the vehicles, just outside the vehicle, along the roadway where the vehicle traveled, andat ambient monitoring sites. The driving scenarios were designed to evaluate the association between in-vehicle pollutant levels and factors such as the carpool lane, traffic congestion, vehicle type, roadway type, time of day, and ventilation setting.
In-vehicle pollutant levels were generally higher in Los Angeles than Sacramento. In Los Angeles, the average in-vehicle concentration of benzene and MTBE range from 10 to 22 g/m3 and 20 to 90 g/m3, respectively. In general, VOC concentrations were similar inside and outside of the vehicle. Vehicle VOC concentrations were higher than at roadway sites which were higher than at the ambient site. Vehicle type and ventilation setting had little effect on in-vehicle concentrations. Other factors such as roadway type and traffic density did have an effect. Details on the exposure estimated during commuting and factors that affect exposure will be given.
This work was not funded by the U.S. Environmental Protection Agency, and therefore, the contents do not necessarily reflect the views of the Agency and no official endorsement should be inferred.