AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Comparing Real-time Simultaneous In-car and Outdoor Particulate and Gaseous Concentrations with a Range of Ventilation Scenarios, Road-types and Traffic Densities
ANNA LEAVEY, Nathan Reed, Sameer Patel, Kevin Bradley, Pramod Kulkarni, Pratim Biswas, Washington University in St Louis
Abstract Number: 239 Working Group: Urban Aerosols
Abstract Increasing commuting times is a modern trend. Advanced automobile technology, improved communication routes, and increases (or decreases) in wealth have enabled (or forced) people to travel increasing distances to work. In the US, average one-way commutes are approximately 30 minutes. Traffic is a major source of particulates and organic pollutants and consequently peak concentrations tend to occur near to or on roads. This is where an individual may receive a disproportionately large fraction of their total daily personal exposures. While there have been numerous commuter exposure studies assessing multiple commuting modes, few studies have focused on car commutes, and fewer still have sought to understand where and why the highest exposures occur.
The objective of this study was to collect real-time simultaneous particulate and gaseous measurements outside and inside of an on-road car operating with either windows open or closed, fan on or AC on, and traveling along different road types with varying traffic densities. The parameters effecting both outside concentrations and outdoor : indoor ratios were then examined. Fifty-four commutes were conducted between September and November, 2014. Mean (SD) indoor total particle counts, PM $_(2.5), lung-deposited surface area and carbon monoxide concentrations were 13,245 (7,615)ptcm$^(-3), 30.4 (6.5)micro-grams m$^(-3), 84.9 (55.6) micro-meter$^(2)m$^(-3) and 1.1 (2.4)ppm respectively, although mean CO concentrations as high as 11ppm were observed. Indoor particle number size distributions demonstrated geometric mean diameters of between 20-30nm, smaller than what is currently reported in the literature. Indoor concentrations were lower and less variable when windows were closed, however travelling behind a gross polluter, for example a school bus, significantly increased exposure levels. Results indicate that a car’s ventilation significantly influences indoor pollutant levels, and that a driver can mitigate their own exposure even whilst traveling through high concentration hotspots.