Notice is hereby given that the U.S. Environmental Protection Agency (EPA) has designated one new reference method for measuring carbon monoxide (CO), one new equivalent method for measuring particulate matter (PM) 2.5 micrometers ([micro]m) or less (PM<INF>2.5</INF>), one new equivalent method for measuring PM 10[micro]m or less (PM<INF>10</INF>), and one new equivalent method for measuring PM<INF>10-2.5</INF> in ambient air.
Source
https://www.federalregister.gov/documents/2026/07/15/2026-14237/ambient-air-monitoring-reference-and-equivalent-methods-designation-of-one-new-reference-method-andCanonical document at the regulator. Always cite this URL — not the Vantage detail page — in compliance evidence.