155. The representative of the United States of America noted that in 2018 the United States Environment Protection Agency (EPA) had announced the Cleaner Trucks Initiative (CTI), a future rulemaking to update standards for nitrogen oxide (NOx) emissions from highway heavy-duty trucks and engines. He emphasized that EPA expected heavy-duty trucks would be responsible for one-third of NOx emissions from transportation in 2025. Updating these standards would result in NOx reductions from mobile sources and could be one important way to facilitate that areas across the United States of America meet air quality standards for ozone and particulate matter. Updating the standards would also offer opportunities to reduce the regulatory burden through smarter programme design. The work has been done in close coordination with the industry as well as federal States and with the interest of other countries. He concluded by ensuring that the United States of America would provide AC.3 with periodic updates on this rulemaking, as it would be developed.