Photo via @abpanphoto
Photo via @abpanphoto

If you noticed something strange in the Baltimore air the other day, you weren’t alone.

According to WBAL, many callers–the bulk of them coming from Parkville–called local fire departments reporting a strange haze, and an even stranger smell, looming along the horizon.

Officials from the Maryland Department of the Environment showed up, as did crews in hazmat uniforms. That level of caution turned out to be unnecessary: the weird smog turned out to be a weather phenomenon known as a temperature inversion, in which warm air traps a layer of cold air near the ground.

The source of the chemical-y smell? Temperature inversions are known for trapping polluted air near the ground, sometimes causing a build-up of pollutants–but not at the level of an airborne toxic event, thankfully.