Global Climate and Human Health Effects of the Gasoline and Diesel Vehicle Fleets.

The global gasoline and diesel fuel vehicle fleets impose substantial impacts on air quality, human health, and climate change. Here we quantify the global radiative forcing and human health impacts of the global gasoline and diesel sectors using the NCAR CESM global chemistry-climate model for year 2015 emissions from the IIASA GAINS inventory. Net global radiative effects of short-lived climate forcers (including aerosols, ozone, and methane) from the gasoline and diesel sectors are +13.6 and +9.4 mW m, respectively. The annual mean net aerosol contributions to the net radiative effects of gasoline and diesel are -9.6 ± 2.0 and +8.8 ± 5.8 mW m. Aerosol indirect effects for the gasoline and diesel road vehicle sectors are -16.6 ± 2.1 and -40.6 ± 4.0 mW m. The fractional contributions of short-lived climate forcers to the total global climate impact including carbon dioxide on the 20-year time scale are similar, 14.9% and 14.4% for gasoline and diesel, respectively. Global annual total PM- and ozone-induced premature deaths for gasoline and diesel sectors approach 115,000 (95% CI: 69,000-153,600) and 122,100 (95% CI: 78,500-157,500), with corresponding years of life lost of 2.10 (95% CI: 1.23-2.66) and 2.21 (95% CI: 1.47-2.85) million years. Substantial regional variability of premature death rates is found for the diesel sector when the regional health effects are normalized by the annual total regional vehicle distance traveled. Regional premature death rates for the gasoline and diesel sectors, respectively, vary by a factor of eight and two orders of magnitude, with India showing the highest for both gasoline and diesel sectors.