AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Regional Climate and Air Quality Impacts of Particulate Emissions from Gasoline Direct-Injection (GDI) Vehicles
SOROUSH ESMAEILI NEYESTANI, Gabriel Kooperman, Rawad Saleh, University of Georgia
Abstract Number: 134 Working Group: Carbonaceous Aerosol
Abstract Due to their enhanced fuel economy, the market share of Gasoline Direct-Injection (GDI) vehicles has increased noticeably over the past decade. However, compared to the traditional port-fuel injection (PFI) engines, GDI engines have been shown to emit higher levels of particulate matter, especially black carbon (BC). BC is an efficient absorber of solar radiation and is a prominent global-warming agent, second only to carbon dioxide. The competing effect of reducing carbon dioxide emissions but increasing BC emissions raises a question regarding the net climate impacts of GDI vehicles. Here, we estimate the regional (over the United States) air quality and climate impacts of switching the U.S. fleet from PFI to GDI vehicles.
We used the Weather Research and Forecasting model coupled with chemistry (WRF-Chem), which simulates both chemical transport and radiative transfer. The simulations were performed at a 12 km resolution and for a period of two months (January and July) in 2011 to take into account the seasonal variability. Using the EPA’s National Emission Inventory (NEI) for 2011 as a base case, we modified the vehicle emission profiles using GDI emissions data obtained from measurements. By comparing the base case (PFI) with the modified one (GDI), we calculated changes in carbonaceous aerosol concentrations and the consequent radiative effect. Our results indicate that shifting the fleet to GDI vehicles leads to a net warming effect over the U.S., with radiative effect as large as 0.5 W/m2 over cities with high transportation activity. Furthermore, using PM2.5 concentrations obtained from the simulations and the concentration-response factor employed by EPA, we calculated spatially resolved PM2.5 caused morality rates. The results indicate that due to the increase in PM2.5 emissions, a shift from PFI to GDI would double the rate of premature deaths attributed to gasoline vehicle emissions.