Final notice to revise the secondary National Ambient Air Quality Standard (NAAQS)
Posted by [email protected] on Jan. 7, 2025 / 2020 Blogs, 2024 Blogs
EPA’s Administrator signed a final notice to revise the secondary National Ambient Air Quality Standard (NAAQS) for oxides of sulfur (SOX) and retains the existing secondary standards for oxides of nitrogen (N oxides) and particulate matter (PM), aligning standards with the best-available science and ensuring air pollution concentrations remain at historically low levels. The revised standard will take effect 30 days after EPA’s decision is published in the Federal Register.
EPA is revising the current 3-hour secondary SO2 standard to be an annual standard of 10 parts per billion (ppb) averaged over three years. EPA is retaining without revision the existing secondary standards for N oxides (annual standard of 53 ppb) and PM (annual PM2.5 standard of 15 micrograms per cubic meter (µg/m3)). More information: https://www.epa.gov/so2-pollution/secondary-national-ambient-air-quality-standards-naaqs-nitrogen-dioxide-no2-and
