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Ground-level Ozone Pollution

Ozone National Ambient Air Quality Standards (NAAQS)

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Rule Summary

On December 23, 2020, EPA completed its review of the full body of currently available scientific evidence and exposure/risk information and decided to retain the existing ozone NAAQS. EPA’s decision is based on its judgment that the current NAAQS protect the public health, with an adequate margin of safety, including the health of at-risk populations, and protect the public welfare from adverse effects. The existing primary and secondary standards, established in 2015, are 0.070 parts per million (ppm), as the fourth-highest daily maximum 8-hour concentration, averaged across three consecutive years.

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