Homeowners know the saying, "water finds a way." Add wildfire smoke to that distinction, another savvy invader harming indoor quality, where people should feel protected from it.

The air quality in Minnesota is improving following a week of lingering wildfire smoke, though wildfires in Canada are still burning. Jeff Wagner spoke to an HVAC technician about how to keep smoke out of a home.

Wildfire smoke has been easy to spot in Minnesota this week, coating the Twin Cities in a brownish haze that obscured the downtown skylines. But experts in lung health are more concerned about the particles you can't see.