Indoor Air Quality & Radon Resources

Why mold grows indoors, where it hides, the humidity level that stops it (below 60%), its health effects, and how to clean it up and keep it from coming back.

Pollen seasons are now 20 days longer. See when tree, grass and weed pollen peak, how pollen gets into your home, and simple ways to reduce it indoors.

What are VOCs? Where they come from (paint, furniture, cleaning products), how they affect health, what TVOC levels mean, and how to lower them at home.

Ideal indoor humidity is 30–50%. See what 55%, 60% and 70% mean for mold and health, the right level in winter, and how to raise or lower humidity.

What do PM1, PM2.5 and PM10 mean? See the difference between particle sizes, safe PM2.5 levels indoors, where particles come from, and how to reduce them at home.

Is the CO2 level in your home too high? See safe ppm levels, the symptoms of high CO2, what causes it, and simple ways to reduce it, including in your bedroom.

Radon is an invisible gas and the leading cause of lung cancer in non-smokers. See a radon levels chart in pCi/L and Bq/m³, what's safe, and when to act.