Air Quality Advisories Caused By Inversion, Particulates

An unusual weather condition produced multiple air quality warnings across Northeast Ohio this week. Officials say levels of particulate matter in the air, combined with humidity and air temperatures, brought about the notices.

Northeast Ohio Area Coordinating Agency’s (NOACA) Joseph MacDonald monitors those conditions and issues advisories. The first half of this week saw light winds and high humidity, he said, along with an event called a temperature inversion. That's when air closer to the ground is cooler than the air above it.

An inversion keeps particulate matter and pollutants from dispersing, McDonald said.

“In some cases, you can have warmer air slide over cooler air because cooler air is heavier,” he says. “That warmer air aloft can actually trap air near the surface.”

Particulate matter comes from combustion, either from activities like burning wood and leaves or from combustion engines. But MacDonald said it’s unclear which particulates caused this specific incident.

“There’s no way to link what specific sources may have produced the elevated levels of fine particulate matter on this particular occasion,” he said.

The region hasn’t exceeded of the standard levels of particulate matter in the air since 2015, MacDonald said, and NOACA won’t know if this week’s levels reached that point until the Ohio Environmental Protection Agency provides a statewide report next year.

Particulate matter is just one reason for a potential air advisory. The EPA and NOACA also monitor levels of carbon monoxide, lead, nitrogen dioxide and sulfur dioxide in the air. Advisories can also be issued for high ozone levels, but MacDonald said those tend to occur between March and October. Levels of particulate matter are monitored year-round.

When an air quality warning is in effect, MacDonald said people should consider carpooling, using public transit, or other travel options that reduce the number of engines on the roads.