US environmental regulators clarify ozone measurement dates for states and tribes

US environmental regulators are correcting a previous rule about how to measure ozone in the atmosphere. This correction clarifies which state, local, and tribal agencies must use the new measurement standard by specific dates in 2025 and 2026.

Measuring ozone accurately is crucial for enforcing air quality standards. When the rules for measurement are unclear, it creates uncertainty for the agencies responsible for monitoring pollution. This clarification means those agencies now know exactly when they must adopt the new standard, which helps ensure consistent and enforceable air quality data across different jurisdictions.