10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Assessing the PM2.5 Imbalance between a Far and Near-Road Location: High Temporal Frequency Source Apportionment and the Role of Black Carbon
UWAYEMI SOFOWOTE, Robert Healy, Yushan Su, Jerzy Debosz, Michael Noble, Anthony Munoz, Cheol H. Jeong, Jon M. Wang, Nathan Hilker, Greg J. Evans, Philip K. Hopke, EMRB, Ontario Ministry of the Environment and Climate Change
Abstract Number: 129 Working Group: Source Apportionment
Abstract The differences in PM2.5 concentrations between two adjacent stations, one situated near a major highway and the other much farther were used to develop a protocol for determining the impact of highway traffic on particulate matter concentrations at the roadside. The near-road station was 2.5. This particulate matter difference, formally called the PM2.5 imbalance was subjectively defined as a case wherein |Near-road PM2.5 - Farther from road PM2.5|/Near-road PM2.5 ≳50%. Of interest was the variation of factors (sources) obtained from source apportionment analyses of the speciation data from the roadside station during these imbalance events. One of the factors, a black carbon factor was determined to be the major cause of the PM2.5 imbalance and was very prominent for the case when PM2.5 concentrations at the near-road station were greater than the farther-station PM2.5. We then regressed the black carbon concentrations observed during these specific events against other traffic-related and meteorological parameters with nonlinear optimization algorithms in our attempts to model any potential relationships. We noted that the traffic counts of heavy duty vehicles (predominantly diesel-powered) dominated the relationship with black carbon while contributions from light duty vehicles were negligible during these [PM2.5]Near-road > [PM2.5]Farther events at the near-road station. This work discusses the most critical ways that highway traffic can contribute to local ambient PM2.5 concentrations that commuters are exposed to and should inform policies and strategies for particulate matter pollution reduction at the roadside.