The EPA's Air Quality Index can tell you whether breathing outside air can be harmful. Here's how to read the scale to plan accordingly in Michigan.

An Air Quality Alert will be in effect through midnight Tuesday for Southeast Michigan, the state's Department of Environment, Great Lakes and Energy announced Monday. The alert is an extension of an existing alert that was issued statewide Saturday and expected to expire Monday night because of drifting wildfire smoke from Canada.

Shower and thunderstorm chances return Wednesday and Thursday with potential for heavy rainfall. There is a marginal (level 1 risk) for storms to reach severe limits on Wednesday. In the wake of a cold front, a cooler and less humid airmass builds in Friday through the weekend.