US EPA initiates new review of National Ambient Air Quality Standards for ozone

23 August 2023

The US Environmental Protection Agency (EPA) announced a new review of the National Ambient Air Quality Standards (NAAQS) for ozone. In October 2021, the EPA announced a reconsideration of the previous Administration’s decision to retain the NAAQS for ozone. The agency is incorporating the ongoing reconsideration into the new review.

Nationally, ozone air quality has been improving—between 2010 and 2022, the national average ozone concentrations have dropped 7%, according to the EPA. However, many areas are still designated as not meeting the current 2015 standards.

The new review will consider information about the latest ozone science and potential implications for the ozone NAAQS provided by the EPA’s Clean Air Scientific Advisory Committee (CASAC) and the Ozone Review Panel. The next steps include:

• Issuing a call for information in the Federal Register in the next few days;
• convening a public science and policy workshop in Spring 2024 to gather input from the scientific community and the public;
• in summer 2024, EPA will summarize the proceedings of the workshop to consider how the information gathered can be used to inform the next review;
• in fall 2024, the agency plans to release its Integrated Review Plan, Volume 2 to guide CASAC consideration and development of the Integrated Science Assessment.

The EPA established the current standards at a level of 70 ppb in 2015 and retained them in 2020, after concluding that there was little new information to suggest the need for revision. The CASAC, however, has identified studies published more recently and also recommended that the EPA conduct additional risk analyses that might support more stringent standards.

Source: US EPA