Use a home air quality monitor to measure PM2.5, PM10, VOCs, CO2, temperature, and humidity
Test for carbon monoxide with CO detectors on every level of the home
Check for radon using a short-term or long-term radon test kit
Inspect for mold by looking for visible growth, musty odors, and moisture problems
Measure humidity levels with a hygrometer to keep indoor humidity in a healthy range
Test for smoke particles with a particulate matter sensor
Use an indoor air quality test kit for formaldehyde and other VOCs
Check ventilation by monitoring CO2 levels in occupied rooms
Test HVAC filters and ducts for dust buildup and contamination
Look for signs of poor air quality such as condensation, stale air, and frequent allergy symptoms
Hire a certified indoor air quality professional for a detailed assessment
Compare readings in different rooms and at different times of day
Repeat tests after cleaning, ventilation changes, or repairs to confirm improvement