Southwest Ohio Air Quality Agency warns Middletown may face federal PM2.5 nonattainment; local monitors show overnight spikes

Carrie Caslin, an environmental specialist with the Southwest Ohio Air Quality Agency, told the Middletown Board of Health on Feb. 11 that recent monitoring near local steel and coke facilities shows elevated fine particulate levels and overnight spikes that may push parts of Hamilton and Butler counties into nonattainment for the updated federal annual PM2.5 standard.

Caslin said the U.S. Environmental Protection Agency last year revised the annual PM2.5 standard from 12 micrograms per cubic meter to 9, and that the Yankee Road and BPG monitors in Middletown “are above [the] annual standard right now,” making the region look likely to move toward nonattainment. She said that determination would trigger additional actions the state and local air agencies must take.

Why it matters: Nonattainment status would require statewide and local planning and could bring new regulatory and mitigation steps — historically including motor-vehicle…