Canadian wildfire smoke transported by northerly winds has driven Columbus AQI into the very unhealthy to hazardous range (200–300+), primarily via elevated PM2.5 concentrations, according to real-time AirNow and Ohio EPA monitoring. This follows a statewide advisory effective July 16, 2026, with similar intrusions noted in prior seasons when stagnant high-pressure patterns limit dispersion. Ground-level ozone formation may add to levels under hot, sunny conditions, though particle pollution dominates the current spike. Traders are tracking National Weather Service wind shifts and potential precipitation that could clear smoke by late week, alongside MORPC daily forecasts and AirNow updates that often resolve markets tied to 100 AQI thresholds. Historical analogs show rapid AQI drops once smoke plumes shift.