Mississippi air quality today

No part of Mississippi is currently designated nonattainment for any federal air standard. The weather does much of that work. Summer here is humid and convective, and afternoons that cloud over and storm are not the clear, stagnant, strongly sunlit afternoons ozone chemistry builds fastest under. There is no terrain to work with either: no valley to invert overnight, no ridge to hold a plume against, and no cold, still winter season for fine particulate to accumulate in the way it does in the interior West.

A statewide clean sheet is also a statement about where the monitors are. Mississippi has no nonattainment area forcing a dense network into existence, so ambient monitoring sits in the places with population and industry and most of the state’s eighty-two counties are not measured at all. DeSoto County, on the Mississippi side of the Memphis metro, runs closest to the ozone standard, at 71 parts per billion in 2024 against a standard of 70. MDEQ works that one through EPA’s voluntary Ozone Advance program alongside the rest of the Memphis metropolitan area rather than under a nonattainment plan.

Smoke here is mostly deliberate. Prescribed fire is routine management in the southern pine, and the Mississippi Prescribed Burning Act sets the terms: a burning permit from the Mississippi Forestry Commission, a written prescription drawn up before ignition, and a certified prescribed burn manager present for the burn. Handling of the smoke belongs in that written plan rather than to the judgment of the day, which is a different regulatory posture from the wildfire states, where the smoke arrives without anyone having filed anything.