Kareem Shaya

As boring as indoor air sounds, it's one of the most important health themes of the decade. According to the EPA, the air within homes can be more seriously polluted than the outdoor air in even the largest and most industrialized cities. And people spend approximately 90% of their time indoors. Particles less than 2.5 micrometers in diameter, also known as fine particles or PM2.5, pose the greatest risk to health. They can get deep into your lungs and some may even get into your bloodstream. From there, they can affect both your lungs and your heart. Indoor PM can be generated through: - cooking: PM2.5 exceeded 250 μg/m3 during some cooking activities (the WHO's guideline for a 24-hour average is 15) - candles: almost 60% of ultrafine particle exposure in homes that burn them - incense: fine particles in large quantities compared to other indoor sources - ultrasonic humidifiers: up to 350 μg/m³, depending on the water types used I've seen what indoor air can do with mold. Only years later did I discover that I'd been living in a mold-infested house. The good news is that most of it is fixable: open a window and run a range hood vented outdoors when cooking, use an evaporative humidifier, and run a HEPA purifier. My bet is we'll look back at indoor air as one of the biggest unforced errors in the health span of our generation.