For comparison to the standard, averaged ambient concentrations of carbon monoxide must be rounded to the nearest integer in parts per million (ppm). Fractional parts of 0.5 or greater must be rounded up. Concentrations of carbon monoxide in ambient air as measured by an approved method, must not exceed:

1. (1) 9 ppm as an eight-hour average concentration more than once per year at any site.

2. (2) 35 ppm as a one-hour average concentration more than once per year at any site.

   NOTE: This rule is included in the State of Oregon Clean Air Act Implementation Plan that EQC adopted under OAR 340-200-0040

Statutory/Other Authority

ORS 468 & 468A

Statutes/Other Implemented

ORS 468A.025

History

DEQ 6-2001, f. 6-18-01, cert. ef. 7-1-01
DEQ 14-1999, f. & cert. ef. 10-14-99, Renumbered from 340-031-0025
DEQ 4-1993, f. & cert. ef. 3-10-93
DEQ 24-1991, f. & cert. ef. 11-13-91
DEQ 8-1988, f. & cert. ef. 5-19-88 (corrected 9-30-88)
DEQ 37, f. 2-15-72, ef. 3-1-72