Air quality and health implications of transitioning 30% of the US Midwest heavy-duty transport fleet from diesel to electric power

Abstract

BackgroundTransitioning to an electric vehicle fleet is an ongoing climate change mitigation action that will reduce tailpipe emissions but increase the energy demand for charging. The subsequent impact this would have on air quality is poorly understood. In this work, we study the effect of transitioning 30% of the heavy-duty fleet in the US Midwest to electric and analyse the corresponding effects on air pollution concentrations and their associated health impacts. MethodsWe scaled tailpipe, refuelling, and idling emissions from heavy-duty vehicles (HDVs) by 30% and estimated the additional energy demand needed for charging. The two-way coupled Weather Research Forecast and Community Multiscale Air Quality chemistry-climate model was used to simulate air pollution concentrations after these emission changes. Monthly simulations for each season were run at a 1·3-km resolution. We estimated the associated health impacts of resultant pollutant concentrations using concentrations response functions derived from epidemiological studies. FindingsCompared with a baseline scenario, we estimate that annual NO2 and PM2·5 concentrations will decrease by up to 4·91 parts per billion and 0·49 μg/m3, respectively, across the study domain. By contrast, differences in annual daily maximum 8-h running mean O3 (MDA8O3) concentrations are spatially heterogenous, with increases along major road networks and metropolitan areas (up to 1·45 parts per billion) and small decreases in less populated regions. We estimate that these changes will lead to a substantial number of NO2 and PM2·5-related avoided deaths and marginal increases in MDA8O3-related health effects. InterpretationOur results highlight the overall beneficial effect of electrifying HDVs on air quality and human health, despite an increase in energy demand. However, policies aimed to transition to an electric vehicle fleet should consider air quality changes with a focus on areas that could experience MDA8O3 increases, leading to adverse health effects. FundingUS National Science Foundation, Ubben Program for Carbon and Climate Science, and Northwestern University.