Ohioans woke up to a hazy, smoky sunrise on July 16 and 17, 2026, as a thick blanket of smoke from hundreds of Canadian wildfires drifted south, prompting a rare series of statewide air quality advisories and health warnings. The Ohio Environmental Protection Agency (Ohio EPA) issued a statewide Air Quality Advisory beginning at 7 a.m. on Thursday, July 16, with the expectation that smoke would enter northern Ohio in the early morning and potentially engulf the entire state by day’s end, according to the Ohio EPA and reporting from USA TODAY and local agencies.
The advisory did not end with Thursday. As the sun rose on Friday, July 17, the advisory was renewed for a second consecutive day, marking a prolonged period of hazardous air for the Buckeye State. The Mid-Ohio Regional Planning Commission (MORPC) compounded the warnings, issuing its fourth straight air quality alert for central Ohio, including Franklin, Delaware, Fairfield, and Licking counties. "Light winds will recirculate dense smoke across central Ohio," MORPC stated, noting that a morning inversion would trap smoke at the surface and pollutant carryover from the previous day would remain high.
The source of Ohio’s smoky skies was clear: more than 800 wildfires burning across Canada, particularly in northwestern Ontario and neighboring regions, with over 100 considered out of control as of July 15, according to USA TODAY. Smoke from these blazes swept across the Great Lakes, blanketing Ohio and threatening to move further east toward New Jersey and the Northeast.
As the smoke settled, air quality monitors across the state registered alarming numbers. The Air Quality Index (AQI)—the Environmental Protection Agency’s tool for communicating outdoor air quality and health—spiked into the “Unhealthy” and even “Hazardous” categories in several cities. On July 16, northern Ohio cities like Canton, Toledo, and Cleveland were under 'Code Red' alerts, with AQI readings between 151 and 200, signaling unhealthy to hazardous conditions. Cleveland fared the worst on July 17, with conditions labeled “Hazardous.” Youngstown registered as “Very Unhealthy,” while Akron and Columbus were “Unhealthy,” and Cincinnati and Dayton sat at “Unhealthy for Sensitive Groups.”
For those unfamiliar, the AQI scale runs from 0 to 500. Scores from 0-50 are considered “Good,” 51-100 “Moderate,” 101-150 “Unhealthy for Sensitive Groups,” 151-200 “Unhealthy,” 201-300 “Very Unhealthy,” and 301-500 “Hazardous.” A 'Code Red' alert, according to AirNow, means air quality is likely to be unhealthy for everyone, while 'Code Orange' signals risk for sensitive groups such as children, older adults, and those with heart or lung conditions.
The health implications of such poor air quality are significant. The Ohio EPA warned that when the AQI is in the “Unhealthy” range, “some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.” Wildfire smoke contains fine particulate matter that can irritate the eyes, throat, and lungs, and exacerbate conditions like asthma or heart disease. The National Weather Service echoed these concerns, stating, “Particles from wildfire smoke can cause minor symptoms, such as mild eye or throat irritation, or more serious heart and lung issues in some cases.”
As a result, authorities advised vulnerable populations—including children, older adults, pregnant individuals, and those with respiratory or heart conditions—to avoid all outdoor activities during the advisory. For the general population, the recommendation was to limit prolonged or strenuous outdoor activity, and to go inside if symptoms such as coughing or shortness of breath developed. “If you continue to experience adverse health effects, please contact your doctor,” the Ohio EPA urged.
Complicating matters further, the state was in the grip of a summer heatwave. The National Weather Service in Wilmington forecast high temperatures of 91 degrees Fahrenheit for July 17, with heat index values potentially reaching 105 degrees. The combination of extreme heat and wildfire smoke made outdoor conditions particularly dangerous, especially for those without access to air conditioning or adequate indoor shelter. Showers and thunderstorms were predicted after 5 p.m. on July 17, offering hope that the rain would help clear the smoke and improve air quality by evening.
With the air thick and hazardous, local agencies and health experts offered practical advice for minimizing exposure. The best protection, according to the Environmental Protection Agency and the Wisconsin Department of Natural Resources, is to stay indoors with windows and doors closed. Using an indoor air purifier, running air conditioning on recirculate with a high-efficiency filter, and avoiding activities that increase indoor pollution—like vacuuming, frying foods, or burning candles—were also recommended. If venturing outside was unavoidable, wearing an N95 mask could help reduce inhalation of fine particles.
For those looking to lessen their contribution to ozone and particulate pollution, MORPC suggested carpooling, biking, using public transit, and waiting until after 8 p.m. to refuel vehicles or mow lawns. “Avoid using gas-powered lawn equipment if possible,” the agency recommended. Even small changes, they argued, could help mitigate pollutant levels during such critical periods.
But what exactly is the AQI, and how is it measured? The Air Quality Index, as explained by AirNow, is measured much like a thermometer, but instead of temperature, it reflects levels of air pollution. The index incorporates data on ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide, providing a simple scale for the public to understand health risks. When air quality deteriorates, as it did in mid-July, the AQI offers a clear, color-coded warning system to help people make informed decisions about outdoor activities.
Even as the smoke began to clear with the arrival of evening showers, the episode served as a stark reminder of how interconnected environmental crises can be. Wildfires burning hundreds of miles away in Canada had direct, tangible impacts on the health and daily lives of Ohio residents. Authorities promised to issue an expiration notice when air quality improved and the smoke had left the region, but the experience left many wondering how often such advisories might become the norm in the future.
For now, Ohioans are keeping an eye on the sky—and the AQI—hoping for clearer, healthier days ahead.