PM2.5 and PM0.1 Exposure Analysis for Oregon's Clean Transportation Fuel Program: Public Health Impacts and Environmental Justice

YITING LI, Michael Kleeman, University of California, Davis

     Abstract Number: 314
     Working Group: Aerosol Exposure

Abstract
Emissions from mobile sources contribute to increased concentrations of airborne particles that cause excess deaths in cities across the United States. This public health burden falls most heavily on the population living closest to major transportation corridors, leading to exposure disparities between different socio-economic classes. Recent studies in California demonstrated that adoption of low carbon fuels can reduce the exposure disparities between socio-economic classes and improve air quality for all people. The state of Oregon recently began adoption of clean transportation fuel policies that are similar to those developed in California, which should likewise yield air quality improvements. Oregon’s policies encourage fuel producers and importers to reduce the carbon intensity (CI) of conventional liquid fuels to meet GHG emission targets. In 2020, Governor Kate Brown issued Executive Order 20-04 specifying a 20% CI reduction by 2030 and a 25% CI reduction by 2035.

Here we analyze the emissions and air quality outcomes of three future scenarios for transportation fuels in Oregon: (i) a Business as usual (BAU) scenario that does not encourage adoption of low carbon fuels, (ii) a Clean Fuel Program (CFP) scenario, which represents adoption and successful achievement of the proposed 25% CI reduction; and (iii) a maximum ambition scenario (CFP MAX), which evaluates a 37% CI reduction. Transportation emissions under all scenarios were analyzed using the MOVES model for every county in Oregon. Detailed emissions with 4 km spatial resolution were then developed for each scenario by scaling the National Emissions Inventory (NEI) for the year 2017 based on the factors from the MOVES analysis. Annual-average air quality in the year 2035 was simulated using the UCD/CIT chemical transport model that enables a detailed analysis of PM2.5, PM0.1, and O3. Exposure fields were analyzed using the BenMAP model to predict public health outcomes stratified by income categories and race / ethnicity categories. Adoption of low-carbon transportation fuels improves air quality in Oregon, yielding public health benefits of approximately $80M/yr. Adoption of low carbon transportation fuels furthermore reduce exposure disparities between residents in different income categories. Changes to exposure patterns based on race/ethnicity were more complex. Exposure patterns differ for PM2.5 and PM0.1 due to the combined effects of infrastructure configuration and population demographics within major cities in Oregon. Implications for the effects of low carbon transportation fuels in Oregon and other locations will be discussed.