Health benefits of decreases in on-road transportation emissions in the United States from 2008 to 2017.

Decades of air pollution regulation have yielded enormous benefits in the United States, but vehicle emissions remain a climate and public health issue. Studies have quantified the vehicle-related fine particulate matter (PM2.5)-attributable mortality but lack the combination of proper counterfactual scenarios, latest epidemiological evidence, and detailed spatial resolution; all needed to assess the benefits of recent emission reductions. We use this combination to assess PM2.5-attributable health benefits and also assess the climate benefits of on-road emission reductions between 2008 and 2017. We estimate total benefits of $270 (190 to 480) billion in 2017. Vehicle-related PM2.5-attributable deaths decreased from 27,700 in 2008 to 19,800 in 2017; however, had per-mile emission factors remained at 2008 levels, 48,200 deaths would have occurred in 2017. The 74% increase from 27,700 to 48,200 PM2.5-attributable deaths with the same emission factors is due to lower baseline PM2.5 concentrations (+26%), more vehicle miles and fleet composition changes (+22%), higher baseline mortality (+13%), and interactions among these (+12%). Climate benefits were small (3 to 19% of the total). The percent reductions in emissions and PM2.5-attributable deaths were similar despite an opportunity to achieve disproportionately large health benefits by reducing high-impact emissions of passenger light-duty vehicles in urban areas. Increasingly large vehicles and an aging population, increasing mortality, suggest large health benefits in urban areas require more stringent policies. Local policies can be effective because high-impact primary PM2.5 and NH3 emissions disperse little outside metropolitan areas. Complementary national-level policies for NOx are merited because of its substantial impacts-with little spatial variability-and dispersion across states and metropolitan areas.

Assessing the health impacts of electric vehicles through air pollution in the United States.

The environmental consequences of electric vehicles (EV) have been extensively studied, but the literature on their health impacts is scant. At the same time, fine particulate matter (PM2.5), for which transportation is a major source, remains an important public health issue in the United States. Motivated by recent developments in epidemiology and reduced-form air pollution modeling, as well as reductions in power plant emissions, we conduct an updated assessment of health benefits of light-duty vehicle electrification in large metropolitan areas (MSAs) in the United States. We first calculate MSA-specific mortality impacts per mile attributable to fine particles from internal combustion engine vehicle (ICEV) tailpipe emissions of PM2.5, SO2, NOx, NH3, and volatile organic compounds, and power plant emissions of PM2.5, SO2, and NOx. We complement these with changes in greenhouse-gas emissions associated with vehicle electrification. We find that electrification leads to large benefits, even with EVs powered exclusively by fossil fuel plants. VMT-weighted mean benefits in the 53 MSAs are 6.9 ¢/mile ($10,400 per 150,000 miles), 83% of which (5.7 ¢/mile or $8600 per 150,000 miles) comes from reductions in PM2.5-attributable mortality. Variability among the MSAs is large, with benefits ranging from 3.4 ¢/mile ($5100 per 150,000 miles) in Rochester, NY, to 11.5 ¢/mile ($17,200 per 150,000 miles) in New York, NY. This large variability suggests incentives should vary by MSA and presents an opportunity to target areas for EV deployment aimed at maximizing public health benefits. Impacts are smaller when EVs disproportionately replace newer ICEV models but EVs still lead to positive benefits in all MSAs. Vehicle electrification in urban areas is an opportunity to achieve large public health benefits in the United States in the short term.