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Accession Number PB2012-113990
Title In-Vehicle Air Pollution Exposure Measurement and Modeling.
Publication Date Jun 2012
Media Count 163p
Personal Author J. Wu R. J. Delfino
Abstract On-road concentrations of traffic-related pollutants are typically much higher than concentrations measured at ambient monitoring stations. This results in in-vehicle microenvironments contributing disproportionately to the total exposure with exposures frequently being as high as on-road concentrations. However, under conditions of low air exchange rate, pollutants with significant in-vehicle losses, such as particles, can have in-vehicle concentrations that are significantly lower than those outside the vehicle. We tested a large sample of vehicles selected to be representative of the California fleet for air exchange rate (AER) at various speeds and found that AER is a predictable function of vehicle age or mileage, speed, and ventilation setting choice (outside air, recirculation, or open windows). We demonstrated that AER is the dominant factor in determining the inside-to-outside ratio for pollutants like ultrafine particles. Models were developed that explain over 79% of the variability in AER and ultrafine particle indoor/outdoor ratios across the California fleet and across the expected range of normal driving conditions. To better determine on-road concentrations, we also conducted extensive on-road measurements using a mobile platform hybrid vehicle with real-time instrumentation. Models were developed and validated to estimate on-road traffic-related pollutant concentrations (variance explained was 37% to 73% depending on the air pollutant and modeling method). Models developed in this study can be combined with subject information about their vehicle, ventilation choices, and commute route to estimate in-vehicle exposures in future studies.
Keywords Air pollution control
Air quality
Concentration (Composition)
Environmental exposure
Health effects
Traffic control
Transportation sector

Source Agency California Air Resources Board Resources Agency
NTIS Subject Category 68A - Air Pollution & Control
85H - Road Transportation
Corporate Author California Univ., Irvine. School of Medicine, Department of Epidemiology.
Document Type Technical report
Title Note Final rept.
NTIS Issue Number 1225
Contract Number CARBRA-07-310

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