The Environmental Protection Agency is on the verge of restoring California’s ability to set strict tailpipe emissions limits, according to news reports, while at the same time looking at adopting a version of the state’s stringent rules for heavy-duty trucks in an effort to cut smog-forming pollution.
The EPA’s restoration of California’s Clean Air Act waiver reverses the Trump administration’s revocation, and the new truck rule aims to drastically reduce nitrogen dioxide emissions from trucks.
Nitrogen dioxide pollution can cause and aggravate respiratory diseases, including asthma and certain kinds of cancer. It can also react with water and oxygen in the atmosphere to form acid rain. The last time the EPA updated emissions limits for heavy-duty trucks, in 2001, it cut nitrogen dioxide by 95 percent over 10 years. That caused nitrogen dioxide pollution to fall 40 percent nationwide.
California has long had the ability to set stricter emissions standards than the rest of the country because of its long history with harmful air pollution caused by cars and trucks. Under the Clean Air Act, other states can adopt the same stricter standards. Seventeen other states and the District of Columbia follow California’s emissions rules.
When Donald Trump took office, automakers petitioned the EPA under Scott Pruitt to review fuel economy standards, and he obliged. Ultimately, Pruitt and his staff rewrote the rules and rescinded California’s waiver, prompting lawsuits.
But scrutiny of the Trump-era rules revealed that in the process of rewriting the rules, EPA officials ignored the conclusions of their agency’s own scientists and relied on a flawed analysis of traffic fatality data to claim that cars and trucks with worse fuel economy were safer.
The California Air Resources Board is in the process of writing regulations that will phase out the sale of new gasoline and diesel cars and light trucks by 2035. Heavy-duty trucks will have to produce zero emissions by 2045. Twelve other states have announced that they’ll also follow California in requiring zero-emissions passenger cars and trucks by 2035.
In December, the EPA announced its own more stringent fuel economy standards that would increase fuel economy by 5–10 percent annually between model years 2023–2026. Less than five years from now, fuel economy stickers on new vehicles will average about 40 mpg, a significant increase from today’s average of about 25 mpg.
The move jibes with automakers’ increased interest in electric vehicles. While even the most efficient gas-powered cars and trucks struggle to exceed 40 mpg without hybrid assistance, even the least-efficient EV on the market today—the Porsche Taycan—hits an equivalent of 69 mpg.