Smoke School Information in Oregon

Oregon Acceptance Status for VirtualOpacity^® — EPA ALT-152A

Accepted.

Oregon Acceptance Letter »

Oregon Visible Emissions / Opacity Standard

The opacity limit for Oregon is 20% opacity (sources installed/constructed/modified on or after June 1, 1970, and all sources inside a special control area); pre-June 1, 1970 sources outside a special control area: 40% opacity through Dec. 31, 2019, then 20% opacity on and after Jan. 1, 2020, as established under OAR 340-208-0110.

Compliance is demonstrated via EPA Method 9 or equivalent; COMS data reduced to 6-minute averages; alternative monitoring method approved by DEQ that is equivalent to Method 9.

Averaging period: 6-min block average

Prior draft said pre-June 1, 1970 sources outside a special control area had 'no standard specified' -- this was incorrect. They are subject to 40% opacity through Dec. 31, 2019, then 20% opacity beginning Jan. 1, 2020. Wood-fired boilers have separate, more detailed provisions under the same rule. Verified against OAR 340-208-0110 primary text.

Last verified July 8, 2026

Note: Regulations change — always verify current requirements with your state's air quality agency before making compliance decisions. This page is for informational purposes and is not legal advice; consult a qualified attorney or environmental compliance professional for guidance specific to your facility.