US EPA tightened the National Ambient Air Quality Standard (NAAQS) for ozone
last year to 0.07 parts per million. The previous ozone NAAQS, finalized in 2008, was 0.075 ppm. The NAAQS is the maximum amount of ozone in the ambient air (air external to buildings to which the general public has access) that is currently considered safe for human health.
The Clean Air Act requires US EPA to review each NAAQS every five years and to revise the standard when necessary. EPA publishes the NAAQS as regulations in 40 CFR 50. Who Enforces Air Quality Rules, and How?
Once EPA sets a new standard, what happens next? Per Section 107 of the Clean Air Act (CAA), air quality standards are enforced at the State level. Each state must evaluate air quality in its jurisdiction and implement a plan to improve and maintain acceptable air quality. Each state submits a State Implementation Plan (SIP) that outlines how State environmental agencies will enforce the regulations and protect air quality, which US EPA must approve.
To achieve this goal, state-level agencies divide their territory into Air Quality Control Regions (AQCR). These control regions are generally congruent with metropolitan areas or with major geographic features that impact air quality (e.g., mountain ranges).
A full list of the AQCRs in your state can be found at 40 CFR 51. What Happens When Clean Air Act Rules Change?
When EPA revises an existing NAAQS standard
(or creates a new one), each US state must revise its SIP to implement whatever changes are needed to:
a. Maintain the new standard in AQCRs that are already in attainment; and/or
b. Improve air quality in AQCRs that are now deemed to be in non-attainment of the new standard. Guidance on EPA’s New Ozone NAAQS Read more about the EPA’s new NAAQS for ozone, including a link to the Final Rule, here
The EPA has issued guidance
on how it plans to work with State and tribal air agencies to implement the new ozone NAAQS.
The EPA provides information on all of the ozone NAAQS (1997, 2008, and 2015) and how they were developed and implemented here
. What New Ozone Rules Mean for You
Ultimately, for industry, a revised ozone NAAQS means that both major and minor sources of ozone, in both attainment and non-attainment areas, can expect the ACQRs to impose new obligations, either through New Source Review (NSR) processes for construction and major maintenance or through Title V operating permits.
Build the expertise needed to make informed on-the-job decisions that help your site control pollution and maintain compliance. Interactive, easy to use, and available 24/7, the Clean Air Act Regulations
will help you get up to speed with new and changing EPA clean air rules and protect your facility from costly EPA enforcement.