Air Pollution Exposure Disparities Related to Sustainable Aviation Fuel in California

MICHAEL KLEEMAN, Yiting Li, Colin Murphy, Jinwook Ro, University of California, Davis

     Abstract Number: 393
     Working Group: Identifying and Addressing Disparate Health and Social Impacts of Exposure to Aerosols and Other Contaminants across Continents, Communities, and Microenvironments

Abstract
Sustainable Aviation Fuel (SAF) made from renewable carbon is the most promising near-term option to reduce GHG emissions from the aviation sector. However, most facilities that produce SAF through lipid hydrotreatment also produce Renewable Diesel (RD) used by trucks in the goods movement sector. Limited feedstocks mean that increasing the production of SAF will reduce the production of RD. Both SAF and RD yield reduced emissions of criteria pollutants relative to their traditional fossil fuel analogs. SAF has lower sulfur content and reduced PM emissions compared to traditional Jet-A fuel. RD has lower PM and NOX emissions compared to traditional diesel fuel. The shift between SAF and RD affects pollutant emissions from on-road diesel trucks, off-road diesel equipment, and aircraft, which could possibly change the health co-benefits, and exposure disparity trends.

In this study, two energy scenarios were developed across California: (i) high SAF adoption featuring a 18.9% SAF blend rate and 30.4% RD blend rate, and (ii) low SAF adoption featuring a 6.8% SAF blend rate and a 45.8% RD blend rate. Future year 2030 air quality simulations were carried out for both emissions scenarios over 32 randomly-selected weeks between 2026-2035 (to account for effects of medium-term meteorological cycles such as ENSO). The UCD-CIT chemical transport model was used to track primary and secondary PM from aviation and diesel sources. Ambient concentration and population exposure to PM2.5, PM number concentration, sulfate, NOX were analyzed. Exposures to PM from on-road diesel, off-road diesel equipment, and aircraft, were then estimated for different socio-economic classes. The results from this study identify the trade-off between SAF and RD in California and compare the benefits of two future energy scenarios across socio-economic classes.