AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Reductions in Airborne PAHs with a Zero Emissions Vehicle Fleet
CYNTHIA WHALEY, Elisabeth Galarneau, Paul Makar, Wanmin Gong, Michael Moran, Craig A. Stroud, Junhua Zhang, Qiong Zheng, Environment and Climate Change Canada
Abstract Number: 347 Working Group: Regional and Global Air Quality and Climate Modeling
Abstract Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous toxic compounds released by biomass burning, industrial activities, and fossil fuel combustion, and they have been identified as pollutants of concern under the U.S. National Scale Air Toxics Assessment program and the Air Toxics in Canada project. Environment and Climate Change Canada’s operational air quality forecasting model, GEM-MACH, was modified to simulate atmospheric concentrations of benzene and seven PAHs: phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, and benzo(a)pyrene. In the model, PAHs are emitted from major point, area, and on- and off-road mobile sources and undergo gas-particle partitioning, atmospheric transport, cloud processing, oxidation, and dry and wet deposition.
The GEM-MACH-PAH high-resolution, limited-area model was run for three summer months, and three winter months in 2009 using two emissions scenarios. The first included all emissions in the two national inventories, and the second omitted on-road mobile emissions of all pollutants, thereby simulating a zero emissions on-road fleet. Hourly output on a 2.5-km grid covering southern Ontario and much of the north-eastern United States was produced. Model predictions of atmospheric concentrations, wet deposition, and gas-particle partitioning were evaluated against measurements from a high spatial resolution field campaign in Hamilton, Ontario, as well as network observations from Canada’s National Air Pollution Surveillance network, the U.S. National Air Toxics Trends Stations network, and the binational Integrated Atmospheric Deposition Network/Great Lakes Basin program.
The model experiment showed that on-road vehicles contribute a substantial fraction of benzene and PAHs at ground level where human exposure occurs. The model domain is home to more than 35 million people, and our results indicate that reductions in mobile emissions could reduce inhalation exposure to these pollutants significantly.