Columbus and the Crock-Pot of meteorological phenomena

Central Ohio has its share of smells: The aroma of doughnuts from the Kroger bakery on Cleveland Avenue, the yeasty scent of the Anheuser-Busch brewery on the North Side, pungent fumes carrying north from a Chillicothe paper plant. Now you can add a new stink to the mix: a mysterious rotten-egg odor that recently smacked folks in the nostrils all over the city.

In December, thousands of people called Columbia Gas to report an odor similar to a natural gas leak. The Columbus Division of Fire also received calls, as did the Delaware County Emergency Management Agency. But no leaks were detected. A mysterious countywide stench occurred in 2014, as well. Some agriculture experts wondered if the smell was caused by rotting radishes that farmers plant in their fields in the fall to add organic material to soil. Others blamed overflow pipes that empty raw sewage into the Olentangy River after heavy rains.

Whatever the source, the odor was made worse by a meteorological phenomenon called temperature inversion, according to weather experts. Under normal conditions, air temperatures decrease the higher you get in the atmosphere. During an inversion, however, warmer air tops cooler air, creating a lid of sorts that can trap odors. Think cabbage in a Crock-Pot.

Bryan Mark, state climatologist and a researcher at Ohio State University, says this can be worse in valleys, such as Salt Lake City, Los Angeles or Denver. “It can hold in pollutants, such as (soot),” he says. “That's why there are tall smokestacks—to punch through local inversions.”

There are more of these than you might imagine, Mark says. You know when you drive along the river in the fall or winter and see a layer of fog above the water? That's temperature inversion.