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Designation of One New Reference Method and Two New Equivalent Methods for Monitoring Ambient Air Quality.
United States Environmental Protection Agency (USEPA) has designated, in accordance with 40 CFR Part 53, one new reference method for measuring concentrations of oxides of nitrogen (NOX) in the ambient air and two new equivalent methods, one for measuring concentrations of ozone (O3) in the ambient air and one for measuring concentrations of sulfur dioxide (SO2) in the ambient air.
The new reference method for NOX is an automated method utilizing the measurement principle based on gas phase chemiluminescence and the calibration procedure specified in Appendix F of 40 CFR part 50. The new equivalent method for O3 is an automated method that utilizes a measurement principle based on non-dispersive ultraviolet absorption photometry. The new equivalent method for SO2 is an automated method that utilizes a measurement principle based on ultraviolet fluorescence.