November to March is the season of inversion conditions in Cache Valley, according Environmental Health Scientist Josh Greer of the Bear River Health Department.
He explains what creates the inversion.
”We get cold air trapped on the valley floor, with warm air above it,” Greer says. “The warm air basically caps that cold air, puts a lid on it. That’s what’s meant by inversion.
“Typically, we see warmer air at the valley floor and cooler air as you go up in altitude. But the inversion is a complete opposite of that.”
While the warm air traps the cold air below, it also traps pollutants. Greer describes the forces that can move the inversion out.
”If we get a good, good snowfall, if we get rain, it will actually clean some of these particles out of the air. But, we get differences in the pressure, too. We have high pressures and low pressures. And once we get those differences with the storm it really helps clear things out.”
Greer says in some parts of Utah high numbers of ozone in the air can cause health challenges. But in Cache Valley it is high numbers of PM 2.5 micron-sized particulates which are so small they become suspended in the air and can do damage to lung tissue.
Greer says about 50 percent of pollution that adds to our PM 2.5 numbers in Cache Valley comes from vehicles.
Those concerned with their health during times of inversion have found sites like air.utah.gov.