Court Upholds AQMD Zero-Emission NOx Rule

On July 2, a federal appeals court upheld a rule by the South Coast Air Quality Management District’s setting a zero-emission Nitrogen Oxide (NOx) standard for water heaters and industrial boilers used in large facilities and manufacturing facilities. The rule will eventually get more than 1 million pieces of equipment to zero-emissions and reduce NOx pollution approximately 5.6 tons per day—roughly equal to eliminating half of all LA area auto emissions. When fully implemented, the boiler rule will avoid over 2,800 early deaths, 11,800 cases of asthma, and 300,000 lost work and school days, yielding over $95 billion in health benefits.

The rule was adopted on June 7, 2024 to achieve compliance with federal ozone standards under the Clean Air Act, was challenged by industry in a lawsuit filed that December, and upheld by a trial court on July 18, 2025, after which it was appealed.

“We secured a huge victory for clean air in the nation’s smog capital,” said Candice Youngblood, Senior Attorney at Earthjustice, which represented People’s Collective for Environmental Justice, Industrious Labs, and Sierra Club as intervenors. “The courts have rejected a cynical effort to stop one of the Los Angeles region’s most significant air pollution reduction rules in decades.”