Spatial Assignment of Emissions Using a New Locomotive Emissions Model

• Published in: Environmental science & technology Vol. 45; no. 13; pp. 5846 - 5852
• Main Authors: Gould, Gregory M, Niemeier, Deb A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.2011
• Subjects: Air Pollutants - analysis; Air Pollution - statistics & numerical data; Applied sciences; Atmospheric pollution; California; Carbon Dioxide - analysis; Carbon Monoxide - analysis; Emissions; Energy and the Environment; Exact sciences and technology; Freight; Hazardous air pollutants; Hydrocarbons - analysis; Models, Theoretical; Nitrogen Oxides - analysis; Outdoor air quality; Particulate Matter - analysis; Pollutants; Pollution; Pollution sources. Measurement results; Railroads - instrumentation; Railroads - statistics & numerical data; Sulfur Dioxide - analysis; Transports; Vehicle Emissions - analysis; California; United States > US; Nitrogen oxide; Sulfur compounds; Locomotive; Hydrocarbon; Carbon dioxide; Motor vehicle; Pollutant emission; Modeling; Sulfur dioxide; Emission inventory; Greenhouse gas; Aerosols; Air pollution; Carbon monoxide; Rail traffic; Organic compounds
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es103660r

Estimates of fuel use and air pollutant emissions from freight rail currently rely highly on aggregate methods and largely obsolete data which offer little insight into contemporary air quality problems. Because the freight industry is for the most part privately held and data are closely guarded for competitive reasons, the challenge is to produce robust estimates using current reporting requirements, while accurately portraying the spatial nature of freight rail impacts. This research presents a new spatially resolved model for estimating air pollutant emissions (hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter less than 10 μm in diameter, sulfur dioxide, and carbon dioxide) from locomotives. Emission estimates are based on track segment level data including track grade, type of train traffic (bulk, intermodal, or manifest) and the local locomotive fleet (EPA tier certification level and fuel efficiency). We model the California Class I freight rail system and compare our results to regional estimates from the California Air Resources Board and to estimates following U.S. Environmental Protection Agency guidance. We find that our results vary considerably from the other methods depending on the region or corridor analyzed. We also find large differences in fuel and emission intensity for individual rail corridors.