COLUMBUS, Ohio (WCMH) — Dozens of cities across the Midwest, including monitoring sites throughout Ohio, attained all-time maximum smoke pollution levels in June that originated with Canadian wildfires, transported southward by unseasonably strong northwesterly winds aloft.

The wildfire season in Canada has burned nearly 46 million acres, nearly three times higher than in any season since records began in 1983, according to the Canadian Interagency Forest Fire Center.

Although the extensive blazes have tapered considerably in recent weeks after an active September with cooler weather and seasonal precipitation, there are still dozens of smoldering fires that are slowly burning out.

An eerie smoke-filled haze filtered sunlight at times and triggered symptoms normally associated with allergies such as sneezing, coughing and watery eyes. Even worse, there are potential health hazards when the Air Quality Index, or AQI, rises above 100.

When smoke plumes blotted out the sun for days at a time, the AQI topped 300 at several monitoring sites, which is considered hazardous for anyone spending time outdoors without a protective mask.

Small particles contained in wildfire smoke reaching the surface and inhaled can enter the bloodstream via the lungs, which can aggravate asthma and other respiratory conditions. The elderly population, people with compromised immune systems and children are at a greater risk of health problems related to air pollution.

Ohio EPA’s Division of Air Pollution Control is responsible for protecting public health by regulating Ohio’s air quality, according to spokesperson James Lee.

“Ohio EPA and eight local air agencies operate and maintain a network of monitoring sites that collect air quality data across the state,” Lee said.

He wrote in an email that more than 100 monitoring sites located across Ohio monitor pollutants including “ozone, small particulates (PM2.5), larger particulates (PM10), sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead.”

Harmful ground-level ozone resulting from a chemical reaction when sunlight interacts with vehicle exhaust, refineries and power plants has been monitored in central Ohio for more than two decades.

Jennifer Van Vlerah, assistant chief at Ohio EPA Division of Air Pollution Control said, “We also have a site that reads particular matter in the air” at the Maple Canyon Fire Station 6 in Columbus.

Lee said that the air monitoring data is “electronically uploaded into Ohio EPA’s air quality database and transmitted every hour of every day to the national AirNow website, which provides continuous real-time air quality data. An interactive smoke map became widely available online in the past year initiated by the U.S. Forest Service and Environmental Protection Agency.

The recent addition of more sensors provided hourly updates that indicated historically high levels of particle pollution, or PM2.5, with diameters generally of 2.5 micrometers or less, occurred in two episodes in June in many Ohio communities.