Air quality and health impacts from using ethanol blended gasoline fuels in China

China's government has announced the mandatory, nationwide use of ethanol blended gasoline fuels (E10, namely, 10% ethanol blend) by 2020. It is necessary to assess the air quality and health impacts of E10 gasoline in China. This study compares two E10 gasoline fuels, ELA (lower content of aromatics) and ELO (lower content of olefins), assuming 100% utilization in the Beijing-Tianjin-Hebei (BTH) and Yangtze-River Delta (YRD) regions in 2030. We found that reduced emissions of primary fine particulate matter (PM2.5) and increased emissions of NOx could be achieved by using both E10 fuels. For nonmethane volatile organic compounds (NMVOC), on-road emissions would be increased by 8% under Scenario ELA and reduced by 3% under Scenario ELO because of the different impacts of the two E10 fuels on evaporation. By using an atmospheric chemical transport model, the annual average reduction in PM2.5 concentrations is estimated to reach nearly 0.2 mu g M-3 in the urban areas under Scenario ELO, while the benefit of the decline of the ambient PM2.5 concentrations is smaller under Scenario EM (<0.1 mu g m(-3)). E10 fuels could increase ambient NO2 concentrations, and the greatest increase, up to 0.4-0.5 mu g M-3 (0.7%-1.5%), is estimated to occur in Beijing. For ozone (O-3) formation, the impacts of the two E10 fuels are different. Scenario EM is estimated to increase ambient O-3 concentrations while Scenario ELO would help reduce O-3, both exhibiting VOC-limited characteristics. We further found that positive health impacts could be achieved by using E10 fuels based on the estimated mortality attributable to long-term exposures to ambient PM2.5 and O-3. 1015 (679-1258) and 790 (522-991) premature deaths are estimated to be avoided in the BTH and YRD regions, respectively, by using the ELO fuel. Future analysis is recommended to investigate detailed species-resolved emissions, more fuel formulas and future vehicle technologies.