New Hampshire will use federal definitions for air pollution, not its own

New Hampshire is changing its state rules to match federal definitions for "hazardous air pollutant" and "regulated air pollutant." This means the state will now use the same list of harmful substances as the US environmental regulators when issuing permits.

For years, states could have their own definitions for what counts as a hazardous air pollutant, leading to different enforcement standards across the country. This change means New Hampshire's air quality rules will now align directly with federal requirements. Companies operating across state lines will face more consistent rules, and environmental groups will have a clearer standard to monitor.