Air Quality Reaches 'Unhealthy' Levels

Residents may have noticed the smoky, reddish haze in the air and the faint smell of burning chemicals in recent days. This is a result of smoke blowing down from widespread wildfires in Canada, affecting air quality in Vilas and its surrounding counties as well as much of the Midwest.

Oneida County Health Department alerted members of the public via its Facebook page this morning (June 4) that air quality had reached "unhealthy" levels for sensitive groups due to particle pollution. This comes after safety notices went out to the public from Vilas and Oneida health departments on May 30 concerning people who may be prone to breathing issues, or those who are elderly or very young as the Air Quality Index moved into the Moderate to Unhealthy categories.

Air quality health is measured by gauging PM2.5 particles. According to Craig Czarnecki, Wisconsin DNR Air Management outreach coordinator, PM2.5 is also known as fine particle pollution —  a general term for a mixture of solids and liquid droplets suspended in the air.

"These fine inhalable particles are very tiny, with a diameter of 2.5 micrometers or less. There are many sources of particle pollution; the most common is combustion-related activities, such as the burning of fuel and wildfires," Czarnecki explained. "These particles can penetrate deep into the respiratory tract and even enter the bloodstream. This can cause health problems, particularly for those in sensitive groups, like people with heart and lung ailments, asthma, children, older adults, and outside workers." 

Data from Air Management's monitoring station in Forest County showed the Air Quality Index for PM2.5 during this weekend's wildfire smoke event ranged from Good (Green) to Moderate (Yellow). As of today, (June 2), levels were considered Moderate, meaning those who are unusually sensitive to particle pollution should consider reducing their activity level or shorten the amount of time they are active outdoors.

Fires have been raging in British Columbia, Manitoba and Saskatchewan, Canada, forcing large-scale evacuations. It is suspected the fires were mainly started by human activity. To keep up with air quality levels here, find the station monitoring data on the DNR's Air Monitoring webpage.

Unusually Intense Fires

Wildfires burning in Canada have had big effects on the Midwest for the last few summers by disrupting outdoor activities. But how does smoke from hundreds of miles away have such a big impact on our area? Czarnecki said that once the smoke separates from the direct impacts of the fire, those plumes can be transported long distances by high- and low-pressure systems.

"Although smoke plumes often remain elevated well above where we live and breathe, a low-pressure system’s frontal boundaries, or the general descending air from a high-pressure system, can sometimes lead to significant smoke impacts at the surface hundreds or even thousands of miles away from where the smoke originated," he said.

Wildfire smoke can sometimes carry with it a plastic-type smell due to the interaction of volatile organic compounds (VOCs) from the wildfire smoke with the ultraviolet radiation from the sun, Czarnecki explained. This reaction in the atmosphere can lead to the creation of benzene and formaldehyde, which is where that burning plastic odor comes from.

Canada is seeing unusually intense fires this year, and in larger numbers, leading to the production of something called pyrocumulus clouds. Czarnecki said that when fires are intense enough, their heat actually has the ability to produce convective (storm) clouds that otherwise would not form.

"In doing so, smoke and ash from the fires is forcefully injected into the upper-atmosphere where winds are stronger and can carry the smoke and ash over long distances. When conditions are right, this smoke and ash can then begin to descend towards the surface hundreds or even thousands of miles away, potentially impacting surface air quality," he said.

As these wildfires have only been happening for the last couple of years, Czarnecki said it's still too early to infer the long-term trends in wildfire activity, but any increase in the frequency, longevity or intensity of wildfire activity in the U.S. or Canada will increase the probability of negative impacts on Wisconsin's surface air quality.