EPA publishes new multi-pollutant emissions standards

The Environmental Protection Agency (EPA) has published stricter emissions standards for both criteria pollutants and greenhouse gases (GHG) in light- and medium-duty vehicles under its Clean Air Act. These new standards would be implemented gradually from model years 2027 to 2032.

Recent advancements in emissions control technology, particularly in vehicle electrification and other advanced vehicle technologies, indicate to the EPA that implementing more rigorous emissions standards is both feasible and economically viable. These standards should result in significant improvements in public health and welfare. However, meeting these needs will necessitate substantial further reductions in both criteria pollutants and greenhouse gas emissions from the transportation sector. To address the public health effects of criteria pollutants such as particulate matter (PM), ozone, nitrogen oxides (NOX), and carbon monoxide (CO), ongoing reductions in these pollutants from transportation sources are imperative.

Overhaul of the GHG Program

In addition to pollutants, the EPA is making changes to its greenhouse gas (GHG) program in various ways. These changes include adjustments to off-cycle and air conditioning credits, considering upstream emissions for zero-emission and plug-in hybrid vehicles. Additionally, there will be updated vehicle certification procedures. The EPA also sets new standards for controlling refueling emissions from certain medium-duty vehicles and establish battery durability and warranty rules for plug-in vehicles. They are also adjusting rules about aftermarket fuel conversions, vehicle imports, emission tests, and fuel economy measurements.

What changes in the new program?

The criteria pollutants program includes stricter emissions standards, revisions to optional credit programs, provisions for durability and warranty of electrified and diesel engine-equipped vehicles, and enhancements to various elements of the existing light-duty program. These standards maintain the trend of reducing emissions levels over the past fifty years for criteria pollutants and the past decade for greenhouse gases. This trend reflects advancements in emissions control technology, enabling significant emissions reductions at reasonable costs.

Predicted benefits of stricter standards

Reducing vehicle emissions would lessen pollution near roads, particularly in areas with heavy traffic. People living, working, or attending school near busy roads face higher health risks due to elevated air pollutant levels. An EPA study found that approximately 72 million individuals reside near truck freight routes, which encompass major highways and roads where light- and medium-duty vehicles operate. Environmental justice research suggests that communities of color and low-income groups bear a disproportionate burden of exposure to elevated pollutant concentrations near major roadways.

See the final rule here.