The Environmental Protection Agency (EPA) proposed on Nov. 22 to tighten limits on nitrogen oxide emissions from fossil fuel-fired power plants as part of its efforts to reduce pollutants.
Nitrogen oxides can form smog when they react with other volatile organic compounds, and high exposure to these gases can lead to asthma and respiratory infections.
The agency estimates that the proposed rule could reduce nitrogen oxide emissions by 198 tons in 2027 and 2,659 tons in 2032, with expected net benefits of up to $46.4 million per year, although it doesn’t break down where the cost savings come from.
The EPA stated that the new standards will rely on the use of combustion controls and selective catalytic reduction, a technology that limits emissions of nitrogen oxides from combustion turbines.
The proposed rule will subcategorize combustion turbines based on their size, their load rates, and the type of fuel they burn (whether natural gas or non-natural gas) to consider their nitrogen oxide emission standards.
The enactment of the proposed rule remains uncertain until after the inauguration of President-elect Donald Trump in January. The EPA last updated its standards on nitrogen oxide emissions in 2006.
The proposed regulation was issued after the Environmental Defense Fund and Sierra Club filed a lawsuit against the EPA in 2022, accusing the agency of failing to fulfill its legal duty to review standards for nitrogen oxide emissions from new gas plants in 16 years.
Under the Clean Air Act, the EPA is required to review new source performance standards for industrial stationary sources, such as power plants, every eight years. The lawsuit resulted in a consent decree that requires the EPA to take final action by November 2025.
Holly Bender, chief energy officer at Sierra Club, has backed the EPA’s proposed rule, urging the Trump administration to finalize the new emission standards when it takes over next year.
“Ultimately, the healthiest option for families across the nation is for power plants to stop burning fossil fuels altogether and for utilities to invest in clean and reliable renewable energy,” Bender said in a statement.
According to the organization, the EPA’s current regulations allow gas-fired power plants to emit up to 15 parts per million of nitrogen oxides, which has remained unchanged for nearly two decades.
Julie McNamara, deputy policy director at the Union of Concerned Scientists, said the new rule will better protect public health and hold fossil fuel companies accountable for reducing air pollution.
“Technology has long been available to significantly lower NOx [nitrogen oxides] emissions from gas plants, but without strengthened standards in place, companies have been taking shortcuts that pad their profits at devastating public cost,” McNamara said.
Nitrogen oxides are sweet-smelling gases released into the air from the exhaust of motor vehicles and the burning of fuel or natural gas, according to the Centers for Disease Control and Prevention.
Everyone is exposed to small amounts of nitrogen oxides in daily life, but high exposure to these gases can lead to health problems, including respiratory issues, the agency notes.
