air pollution, air quality, ethanol, ethanol blending, gasoline, particulates
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New Report on Air Pollution From Gasoline Powered Vehicles

Submitted by EFC Team on December 28th, 2016

A new report by Energy Future Coalition Summer Fellow, Sadaf Sobhani, on “Air Pollution from Gasoline Powered Vehicles and the Potential Benefits of Ethanol Blending” is now available. The report provides a review of particulate, nitrogen oxide, and volatile organic compound pollution.


Each gallon of hydrocarbon-rich petroleum fuel that is used to power vehicles today produces nearly 20 pounds of carbon dioxide (CO2), resulting in the annual emission of over 1.5 billion metric tons of CO2, or roughly 1/3 of the total greenhouse gas emissions in the United States [1]. Efforts to curb climate change effects and reduce the greenhouse gas emissions from the transportation sector have resulted in stricter Corporate Average Fuel Economy Standards (CAFE) and policies such as the Renewable Fuel Standard (RFS) to develop alternative fuels. In addition to CO2 emissions and its global warming effects, the concerns regarding vehicle emissions include toxic compounds such as carbon monoxide (CO) and nitrogen oxides (NOx), which have significant epidemiological and environmental consequences. Control of hydrocarbons and CO first began in California in 1966, followed by standards set by the federal government in 1968. The 1970 amendment to the Clean Air Act (CAA) tightened the initial emissions standards and added NOx as the third major pollutant emitted by vehicle engines [2]. Under the current CAA, the U.S. Environmental Protection Agency (EPA) is required to set standards for six principal air pollutants: ozone, particulate matter, lead, CO, nitrogen dioxide and sulfur dioxide. Airborne pollutants, including both primary tailpipe emissions (e.g. CO) as well as secondary chemical species formed via atmospheric reactions (e.g. ozone), can travel into the respiratory system and through the human body, causing potentially chronic health effects. Ambient and indoor air pollution result in over 5 million deaths a year, globally. In 2013, air pollution was the 4th highest ranking risk factor for death in the world [3]. Although exhaust emissions regulation in the last 50 years has resulted in significantly lower concentrations of toxic airborne pollutants in the United States, an estimated 9,320 deaths in 2013 were attributed to air pollution exceeding the American Thoracic Society (ATS) recommended standards [4]. This statistic is comparable to the 10,076 alcohol-related traffic deaths that occurred in that same year, illustrating that air pollution control remains as a highly relevant national public health concern that
necessitates strong policies in parallel to those initiated to reduce CO2 emissions. This report reviews the recent literature on particulate matter, NOx, and volatile and semi-volatile organic compounds that result in ozone pollution. Emissions from automobiles are directly linked to fuel composition and engine technology, therefore this report also reviews the key concepts in engine performance (e.g. fuel octane rating, fuel injection technique, etc.). Results from numerous scientific studies are presented to show the current understanding of the sources and potential impacts of emissions from automobiles, focusing on the influences of specific gasoline components and ethanol-gasoline blending.

[1] United States Department of Energy, Energy Information Administration. How much carbon dioxide is
produced by burning gasoline and diesel fuel?
[2] Joseph T Kummer. Catalysts for automobile emission control. Progress in Energy and Combustion
Science, 6(2):177–199, 1980.
[3] Mohammad H Forouzanfar, Lily Alexander, H Ross Anderson, Victoria F Bachman, Stan Biryukov,
Michael Brauer, Richard Burnett, Daniel Casey, Matthew M Coates, Aaron Cohen, et al. Global,
regional, and national comparative risk assessment of 79 behavioural, environmental and occupational,
and metabolic risks or clusters of risks in 188 countries, 1990–2013: a systematic analysis for the global
burden of disease study 2013. The Lancet, 386(10010):2287–2323, 2015.
[4] Kevin R Cromar, Laura A Gladson, Lars D Perlmutt, Marya Ghazipura, and Gary W Ewart. American
thoracic society and marron institute report. estimated excess morbidity and mortality caused by air
pollution above american thoracic society–recommended standards, 2011–2013. Annals of the American
Thoracic Society, 13(8):1195–1201, 2016.


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