The PM Challenge

• By: AWMA
• On: 09/01/2026 14:27:41
• In: EM Articles
• Comments: 0

by Eric L. Hiser

In February 2025, EM devoted an issue to “The PM Challenge” that reviewed the evolution of the particulate matter National Ambient Air Quality Standards (NAAQS) from total suspended particulate (TSP) through PM10 and PM2.5, and discussed the various measurement techniques for PM's various forms, including filterable particulate matter measured by Methods 5, 201 and 201A among others; condensable particulate matter measured by Method 202, and secondary particulate matter formed by the atmospheric interaction of nitrogen oxides (NOx), sulfur dioxide (SO2), and in some cases, volatile organic compounds (VOCs) and ammonia (NH3).

The February 2025 issue focused on measurement issues, including a report by David Nash and Paul Van Rooy on  the U.S. Environmental Protection Agency's (EPA) efforts to improve measurement; concerns with existing technologies and their limitations outlined by Rich Trzupek from Alliance Technical Group, a stack tester; and the challenges in trying to use these data to model future conditions by Bill Jones with Blue Sky Modeling.

This issue picks up from that issue and builds out both promising developments in understanding PM data to better control and permit sources of PM, as well as some of the continuing limitations of the methods and steps sources can take to address those limitations. 

Continue reading the full September 2026 issue of EM.