Smoke School Information in Pennsylvania

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

Pending Acceptance.

Pennsylvania Visible Emissions / Opacity Standard

The opacity limit for Pennsylvania is No emission equal to or greater than 20% opacity for periods aggregating more than 3 min in any 1 hour; never equal to or greater than 60% at any time, as established under 25 Pa. Code Sec. 123.41(1)-(2); exceptions Sec. 123.42; alternative limits Sec. 123.45.

Compliance is demonstrated via EPA Method 9 (40 CFR Part 60, Appendix A; Chapter 139 of PA Code); observer certification required; Alternative Opacity Limitations (§ 123.45) available when source complies with mass-based PM limit.

Averaging period: Aggregate: >3 minutes in any 1 hour = violation; no single period may equal or exceed 20%

Pennsylvania uses an aggregate minutes approach: exceeding 20% opacity for aggregate >3 minutes in any 1 hour is a violation, similar to Delaware and Rhode Island rather than the common '6-minute block average' structure. PA also has an Alternative Opacity Limitation (AOL) process under §123.45 for sources that comply with mass PM standards.

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.