An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

News Releases

News Releases from Region 09

EPA Advances New Initiative to Reduce Polluting Emissions from Trucks in Arizona

Contact Information: 
Soledad Calvino ( )

PHOENIX — Today, at an event with Phoenix Mayor Gallego, officials from state and local agencies, and members of the American Trucking Association, the U.S. Environmental Protection Agency (EPA) announced steps to advance the national Cleaner Trucks Initiative (CTI) in Phoenix, Arizona. The CTI aims to establish through rulemaking more stringent emissions standards to reduce nitrogen oxide (NOx) and other pollutants from heavy-duty truck engines.

“Through this initiative, we will modernize heavy-duty truck engines, improving their efficiency and reducing their emissions, which will lead to a healthier environment,” said EPA Pacific Southwest Regional Administrator Mike Stoker. “The U.S. has already made major reductions in NOx emissions, but through this initiative we will continue to reduce emissions while spurring innovative new technologies, ensuring heavy-duty trucks are clean and remain a competitive method of transportation.”

The CTI rulemaking follows petitions from over 20 organizations, including state and local air agencies, to revise and promulgate more stringent NOx standards.

EPA held the event at a City of Phoenix Public Works Department (CPPWD) facility. Last year CPPWD received a $1 million grant from the EPA to replace ten diesel trucks with ultra-low emission NOx compressed natural gas (CNG) trucks. These upgrades are estimated to reduce NOx emissions by 1.8 tons, fine particulate matter by 0.1 ton, hydrocarbons by 0.1-ton, carbon monoxide by 0.4 ton, and carbon dioxide by 48.4 tons. The project will also conserve over 75,000 gallons of diesel fuel by employing ultra-low NOx emission CNG engine technology.

“Clean air is essential to the well-being of Phoenix’s residents and visitors and paramount to our continued success. As the fifth largest and fastest growing city in the nation, we must set a strong example in reducing emissions. Currently, the number one producer of emissions in the Valley is vehicles,” said Phoenix Mayor Gallego. “We are proud to partner with the EPA in our effort to reduce our city’s fleet emissions and educate other communities on the importance of a cleaner future.”

From 2007 to 2017, U.S. NOx emissions dropped by more than 40 percent, but there is more work to be done. Today, over 100 million people live in areas where ozone and particulate matter (PM) levels exceed air quality standards, and, according to EPA estimates, heavy-duty vehicles will continue to be one of the largest contributors to NOx emissions — a precursor of ozone and PM formation — from the transportation sector in 2025. Updating emissions standards will result in significant NOx reductions, which will aid communities across the country in bringing down ozone and PM levels to EPA’s National Ambient Air Quality Standards.

EPA last revised NOx standards for on-highway heavy-duty trucks and engines in January 2001. Pursuant to the Clean Air Act, the CTI will provide manufacturers sufficient time to comply with new standards and ensure that updated standards consider feasible emissions control technologies. Working together with state and industry partners, we can achieve environmental results through the pursuit of commonsense regulations that encourage economic growth.

EPA intends to publish a proposed rule in early 2020.

Learn more about the Cleaner Trucks Initiative here:

Learn more about EPA’s Pacific Southwest Region. Connect with us on Facebook and on Twitter.