Potential emission reductions by converting agricultural residue biomass to synthetic fuels for vehicles and domestic cooking in China

Abstract

Vehicle exhaust and transported biomass burning emissions are important air pollution sources in many urban areas, and domestic cooking with biomass fuels causes indoor air pollution in many rural areas. Using agricultural waste-generated synthetic fuels can reduce emissions both from vehicles and biomass burning. To estimate the potential benefits of synthetic diesel in Beijing, the emission factor model for the Beijing vehicle fleet was applied to estimate exhaust emissions for the 2015–2030 period. Compared with 100% petroleum diesel, a 20% synthetic diesel blend reduced diesel fleet emissions by 24% for carbon monoxide, 30% for total hydrocarbons, 5.5% for nitrogen oxides, and 19% for fine particulate matter with an aerodynamic diameter of ≤2.5μm (PM2.5) while using 100% synthetic diesel decreased emissions by 36% for carbon monoxide, 48% for total hydrocarbons, 10% for nitrogen oxides, and 34% for PM2.5. The use of biomass for producing synthetic fuels rather than burning in the field also reduces air pollution. Over 60g of PM2.5 agricultural open-field burning emissions are avoided per liter of synthetic fuel produced. Replacing solid crop residues with synthetic liquid fuels in household cooking would reduce PM2.5 emissions by more than 90%.