The United States Environmental Protection Agency (“EPA”) in a May 11th Federal Register Notice states in accordance with 40 CFR Part 53, it has designated a new equivalent method for measuring concentrations of nitrogen dioxide (“NO2”) in the ambient air. See 82 Fed. Reg. 21995.

EPA states it evaluates various methods for monitoring the concentrations of those ambient air pollutants for which the agency has established National Ambient Air Quality Standards (“NAAQS”) pursuant to the Clean Air Act.

The agency notes that monitoring methods that are determined to meet specific requirements for accuracy are designated by it as either reference methods or equivalent methods (as applicable). If determined to meet such requirements, they may be used under 40 CFR Part 58 by states and other agencies for determining compliance.

Note that a list of all reference or equivalent methods that have been previously designated by EPA may be found at

The May 11th Federal Register notice announces the designation of a new equivalent method for measuring concentrations of NO2 in ambient air. It is described as an automated method (analyzer) and is described in the announcement.

An application for an equivalent method determination for what the agency characterizes as a “candidate method” had been received by the agency on January 23, 2017. The analyzer is stated to be commercially available from the applicant:

2B Technologies, 2100 Central Avenue, Suite 105, Boulder, CO 80301

A copy of the Federal Register notice can be downloaded here.