Most of us spend a lot of our lives indoors — reports say that people in the US, the UK and Canada are inside about 90 percent of the time. Those same reports also note indoor air can be far more polluted than outdoor air, thanks to things like cooking emissions, building materials, cleaning supplies and pet dander. One way to clear the air is to increase ventilation, which can be as simple as opening up windows. But if the air outside is also unhealthy — such as from wildfires, smog or a high... Read this story