The US Environmental Protection Agency (EPA) has approved two requests from the California Air Resources Board (CARB) for waivers to implement and enforce its Advanced Clean Cars II (ACC II) regulations for light-duty vehicles and its omnibus low nitrogen oxides (NOx) regulation for heavy-duty highway and off-road vehicles and engines, according to a news release on Wednesday December 18.

Under the Clean Air Act, California has the ability to adopt emissions requirements independent from EPA standards to meet the state’s significant air quality challenges. The state must seek a waiver from the EPA for new motor vehicle emission standards.

After reviewing the information provided by California, reviewing comments submitted by the public and applying the limited criteria for waiver review under the Clean Air Act, the EPA determined in each case that it would be appropriate to grant both waiver requests.

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