OAR 340-202-0070: Ambient Air Quality Standards: Sulfur Dioxide

Concentrations of sulfur dioxide in ambient air as measured by an approved method for each averaging time must not exceed the following concentrations: (1) Annual average: 10 ppb as a three-year average of annual arithmetic means for any calendar year at any monitoring site as determined by appendix T of 40 C.F.R. part 50, and as measured by the reference method described in appendix A-1 of 40 C.F.R. part 50 or as measured by an equivalent method designated in accordance with 40 C.F.R. part 53. (2) 1-hour average: 75 ppb as a three-year average of the annual 99th percentile of the daily maximum 1-hour average concentrations recorded at any monitoring site as determined by appendix T of 40 C.F.R. part 50, and as measured by a reference method based on appendix A-1 of 40 C.F.R. part 50, or as measured by an equivalent method designated in accordance with 40 C.F.R. part 53. NOTE: This rule is included in the State of Oregon Clean Air Act Implementation Plan that EQC adopted under OAR 340-200-0040. NOTE: View a PDF of referenced EPA Methods by clicking on "Tables" link below. [ED. NOTE: To view attachments referenced in rule text, click here to view rule.]