Air quality alarm sparked by still air, melting snow

METRO DETROIT — A “perfect storm” of weather conditions and seasonal trends prompted state officials to issue an air quality alert over a mid-February weekend.

Michiganders were alerted to an air quality advisory for the weekend of Feb. 14-16 due to high concentrations of particulates about 2.5 micrometers in size, a group of hazards known collectively as PM2.5. This concentration of PM2.5 raised air quality indexes across the region into the 101-150 AQI range that indicates a health risk for sensitive groups such as the elderly, pregnant, children or those with medical conditions.

Air quality concerns as of late tend to be due to wildfire smoke, but no distant fires could be blamed for the buildup of particulates that sparked the mid-February alert. Alec Kownacki, a meteorologist with the Michigan Department of Environment, Great Lakes and Energy, says the causes are a blend of seasonal snow melts, windless air and normal emissions buildup.

“(On) the 12th or so we started seeing temperatures creep up into the 40s and the 50s across the entire weekend. We had multiple days with well above average temperatures and sunny skies — it was great weather for the middle of February,” Kownacki said. “But we also had high pressure sitting over us. What happens when there’s high pressure sitting over us (is) it creates a dome or a bubble in the atmosphere, so basically there is no air movement.”

The high temperatures and high pressure dome paired up with cooling caused by snow melting across lower Michigan, which caused an atmospheric inversion that traps air in lower altitudes. The inversion trapped the emissions from vehicles and other pollution sources near to the ground, creating conditions where fine particulates build up and lower the air quality.

While melting events like this are common for the back end of winter, it is the particular blend of elements that pushed the Feb. 14-16 weekend’s melt into potentially hazardous territory.

“It was basically just a perfect storm,” Kownacki said. “It was warmer temperatures over a snowpack that was melting, so you have that atmospheric inversion that sets up. And then you add the emissions from day-to-day life in southeast Michigan that’s accumulating over multiple days that’s just sitting there (and) not dispersing. Even a light breeze helps disperse those emissions and concentrations out of the area, but that wasn’t occurring.”

But what exactly was building up over the weekend? Kownacki says it was more industrial and vehicle related particulates — think car exhaust, factory emissions, tire rubber wearing away and similar such compounds — rather than the burnt-up plants and manufactured materials that make up wildfire smoke. That said, getting a lung full of fine particulate matter is undesirable no matter where those particulates come from.

“The particulate is way smaller than a human hair, so it gets into your blood stream,” Kownacki said. “It gets into your lungs. It’s not particularly good for human health, and that’s why we have our threshold for alerts (that) start at the orange level.”

Dr. Natasha Bagdasarian, chief medical executive for the state of Michigan, says lungs are not the only parts of the body at risk when inhaling polluted air.

“We actually see cardiovascular impact, people having impacts to their heart and other organs from repeat, routine exposure to this type of particulate matter,” Bagdasarian said. “This can even be associated with risk for early mortality and other types of outcomes.”

When the air quality index reaches 100 and higher, Bagdasarian recommends at-risk people remain indoors and reschedule any outdoor activities they have planned for the risk period. Those at lower risk should limit their time breathing air outside, either going out in short bursts or wearing a mask if they need to be out for an extended period of time. Once the AQI reaches 201 or higher, everyone should stay indoors.

Those looking to remain ahead of the air quality curve can sign up for notifications through airnow.gov and enviroflash.info to be alerted whenever air quality levels become potentially dangerous.