Emissions of nitrogen oxides (NOx) from road vehicles have fallen considerably in the United States since the Clean Air Act was passed in 1970, when they totaled 12.6 million tons. Since then, increasingly stringent standards have resulted in NOx emissions from road vehicles to fall to a low of 2.2 million tons in 2021. This was a reduction almost 80 percent compared with 2002 levels.
Heavy-duty trucks are a major source of transportation emissions in the U.S.. In November 2020, the EPA announced the launch of the Clean Trucks Initiative in a bid to decrease NOx emissions from HDVs.
Annual nitrogen oxide (NOx) emissions from road vehicles in the United States from 1970 to 2021*
(in 1,000 tons)
*On-road" or highway sources include vehicles used on roads for transportation of passengers or freight.
**2002 and 2005 MOVES data were used to update 2002-2007. The change in model resulted in noticeable changes in highway emissions from 2001 to 2002 for various pollutants
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Environmental Protection Agency. (February 10, 2022). Annual nitrogen oxide (NOx) emissions from road vehicles in the United States from 1970 to 2021* (in 1,000 tons) [Graph]. In Statista. Retrieved August 13, 2022, from https://www.statista.com/statistics/1234938/road-transportation-nitrogen-oxide-emissions-us/
Environmental Protection Agency. "Annual nitrogen oxide (NOx) emissions from road vehicles in the United States from 1970 to 2021* (in 1,000 tons)." Chart. February 10, 2022. Statista. Accessed August 13, 2022. https://www.statista.com/statistics/1234938/road-transportation-nitrogen-oxide-emissions-us/
Environmental Protection Agency. (2022). Annual nitrogen oxide (NOx) emissions from road vehicles in the United States from 1970 to 2021* (in 1,000 tons). Statista. Statista Inc.. Accessed: August 13, 2022. https://www.statista.com/statistics/1234938/road-transportation-nitrogen-oxide-emissions-us/
Environmental Protection Agency. "Annual Nitrogen Oxide (Nox) Emissions from Road Vehicles in The United States from 1970 to 2021* (in 1,000 Tons)." Statista, Statista Inc., 10 Feb 2022, https://www.statista.com/statistics/1234938/road-transportation-nitrogen-oxide-emissions-us/
Environmental Protection Agency, Annual nitrogen oxide (NOx) emissions from road vehicles in the United States from 1970 to 2021* (in 1,000 tons) Statista, https://www.statista.com/statistics/1234938/road-transportation-nitrogen-oxide-emissions-us/ (last visited August 13, 2022)
