EPA unveils new model to measure transportation emissions

Source: Amanda Peterka, E&E reporter • Posted: Wednesday, October 8, 2014

U.S. EPA today made available to states an updated computer model to measure different types of air pollution stemming from the transportation sector.

The new model will be available for use in all states but California, which uses its own computer program to quantify transportation emissions. EPA said states should start using the new model to shape required Clean Air Act pollution control plans, and in two years, the agency plans to require it for certain types of air quality analyses.

EPA first released information about the update in July, but officially made the new model available and started the clock ticking on the two-year grace period today in a Federal Register notice.

“It represents the agency’s most up-to-date assessment of on-road mobile source emissions,” EPA said.

EPA said the new model also represents its best tool for measuring greenhouse gas emissions from the transportation sector.

The Motor Vehicle Emission Simulator, first released in 2009 and last revised in 2010, is based on millions of emission test results, according to EPA. The latest revision takes into account new data on light- and heavy-duty vehicles, exhaust emissions and various fuel effects, including the air impact of adding ethanol to gasoline. It also incorporates new emissions standards, including EPA’s greenhouse gas standards for heavy- and light-duty vehicles, and the agency’s Tier 3 vehicle standards.

Compared to the older 2010 model, the new one generally shows greater decreases over time of volatile organic compounds, nitrogen oxides, particulate matter and carbon monoxide emissions from the transportation sector, according to EPA. Particulate matter concentrations, on the other hand, vary depending on the area of the country.

The two-year grace period applies to the use of the model for analyzing carbon monoxide, coarse particle and fine particle pollution hot spots. At the end of the grace period, MOVES14 will also be required for the regional emissions analyses done by states to show that highway and transit projects are consistent with air quality goals.

EPA said states should start using the model as soon as possible in their state implementation plans written to meet the federal ozone, carbon monoxide, particulate matter and nitrogen oxide standards. The Clean Air Act requires states to use the most up-to-date information and models in developing those plans, and the failure to use the new model to quantify transportation emissions could result in EPA finding states out of compliance with the statute.

But EPA also said it would give states that have done significant work in developing pollution control plans under the old model leeway to continue using the old model.