Life cycle air quality impacts of conventional and alternative light-duty transportation in the United States

Abstract

Commonly considered strategies for reducing the environmental impact of light-duty transportation include using alternative fuels and improving vehicle fuel economy. We evaluate the air qualityrelated human health impacts of 10 such options, including the use of liquid biofuels, diesel, and compressed natural gas (CNG) in internal combustion engines; the use of electricity from a range of conventional and renewable sources to power electric vehicles (EVs); and the use of hybrid EV technology. Our approach combines spatially, temporally, and chemically detailed life cycle emission inventories; comprehensive, fine-scale state-of-the-science chemical transport modeling; and exposure, concentration-response, and economic health impact modeling for ozone (O 3 ) and fine particulate matter (PM 2.5 ). We find that powering vehicles with corn ethanol or with coal-based or "grid average" electricity increases monetized environmental health impacts by 80% or more relative to using conventional gasoline. Conversely, EVs powered by lowemitting electricity from natural gas, wind, water, or solar power reduce environmental health impacts by 50% or more. Consideration of potential climate change impacts alongside the human health outcomes described here further reinforces the environmental preferability of EVs powered by low-emitting electricity relative to gasoline vehicles.S ociety is in the midst of a great effort to understand and mitigate anthropogenic greenhouse gas (GHG) emissions and their effects on the global climate (1-5). However, GHG damages are not the only environmental impact of human activities, and are often not even the largest. In transportation, for example, non-GHG air pollution damage externalities generally exceed those from climate change (6-8). Here, we explore the air quality impacts of several proposed transportation fuel interventions: liquid biofuels (9), electric vehicles (EVs) powered by conventional and alternative energy sources (3), biomass feedstocks to power EVs (10, 11), compressed natural gas (CNG) powered vehicles (5), and improved vehicle fuel economy.The air quality impacts of biofuels, transportation electrification, CNG vehicles, and improved fuel economy have been studied (refs. 7, 8, and 12-21; results are summarized in Table S1); our work advances prior research by combining estimates of life cycle emissions [i.e., emissions from production ("upstream") and consumption ("tailpipe") of the fuel] with an advanced air quality impact assessment. In addition, we incorporate greater spatial, temporal, and chemical detail than have prior research efforts. We also report non-GHG air quality life cycle impacts of biomass-powered EVs, which to our knowledge have not yet been described.We use a spatially and temporally explicit life cycle inventory model (22) to estimate total fuel supply chain air pollutant emissions for scenarios where 10% of US projected vehicle miles traveled in year 2020 are driven in 1 of 11 types of passenger cars: (i) conventional gasoline powered vehicles (abbrevi...

Global Association of Air Pollution and Cardiorespiratory Diseases: A Systematic Review, Meta-Analysis, and Investigation of Modifier Variables

“…Razeghi et al 41 examined the association between power generation, transportation, and air quality in the United States, and they found that O 3 and PM 2.5 decreased with the introduction of wind energy to the grid mix and the use of plug-in electric vehicles. Tessum et al 42 evaluated air quality (PM 2.5 and O 3 )-related human health impacts of fuel type including the use of electric vehicles, and the use of electricity from a range of conventional and renewable sources. The authors found that the health impacts varied by 80% depending on the use of fuel and electricity source.…”

Are There Environmental Benefits from Driving Electric Vehicles? The Importance of Local Factors

“…In contrast to prior work, we report damages within the county of emission, within the state of emission, and in total (across all receptors). 10 Babaee, Nagpure, and DeCarolis (2014); Graff Zivin, Kotchen, and Mansur (2014); Michalek et al (2011);and Tessum, Hill, and Marshall (2014) analyze the benefits of electric vehicles at the aggregate level. Li et al (forthcoming) consider variation in damages from electric vehicles but assume uniform damages from gasoline vehicles.…”

Advances and critical aspects in the life-cycle assessment of battery electric cars

“…67,76,107,108 Chinese LCA studies, however, partly quantify CO 2 emission advantages for BEVs in their home country 109 where electricity is largely produced from coal. A collaborative US-Chinese LCA study assessed the use of BEVs in six Chinese provinces as unfavorable with respect to their carbon footprint, which may, however, improve in the future because of advances in power plants' emissions control.…”