Testing
Do smart air quality monitors detect radon?
Short answer
Only if the monitor has a radon sensor. Home air monitors detect only the pollutants they are designed for, and many measure particles, carbon dioxide or chemicals but not radon; a monitor measures radon only if its specifications list radon and give readings in pCi/L or Bq/m3.
In brief
Most air quality monitors do not measure radon
These devices are low-cost air pollution monitors, also sold as air sensors, air quality sensors, air quality monitors, air pollutant monitors, meters or detectors. Depending on the sensor or sensors inside, each detects one or more pollutants or conditions. The ones sold in the U.S. are designed to detect particulate matter (PM), radon, carbon monoxide (CO), carbon dioxide (CO2), formaldehyde, volatile organic compounds (VOCs), and environmental factors such as temperature and humidity. Radon is on that list, but only for monitors built with a radon sensor.
Check the label
How to tell whether your monitor measures radon
Read the list of sensors
The specifications name each thing the device detects. If radon is not named, it does not measure radon.
Look for a radon unit
A radon reading is given in picocuries per liter (pCi/L) in the U.S. or becquerels per cubic meter (Bq/m3); EPA's 4 pCi/L action level is 148 Bq/m3. A score, a color or an air quality index is not a radon reading.
Check how long it needs
Radon varies from day to day and season to season, so a reading over hours tells you less than an average over days or months. A radon monitor reports an average over its test period.
| General air quality monitor | Radon monitor or radon test | |
|---|---|---|
| What it detects | Commonly particles, CO2, VOCs, temperature and humidity | Radon, and sometimes other factors as well |
| Unit | Micrograms per cubic meter, parts per million or an index | pCi/L or Bq/m3 |
| What to compare the result with | There are no widely accepted indoor limits for most pollutants | EPA's action level of 4 pCi/L (148 Bq/m3) |
What it detects
- General air quality monitor
- Commonly particles, CO2, VOCs, temperature and humidity
- Radon monitor or radon test
- Radon, and sometimes other factors as well
Unit
- General air quality monitor
- Micrograms per cubic meter, parts per million or an index
- Radon monitor or radon test
- pCi/L or Bq/m3
What to compare the result with
- General air quality monitor
- There are no widely accepted indoor limits for most pollutants
- Radon monitor or radon test
- EPA's action level of 4 pCi/L (148 Bq/m3)
Reliability
How accurate home monitors are
There is limited information on how accurate and precise the low-cost monitors on the market are, and accuracy can be affected by where the monitor sits, how long it has been in use, temperature, relative humidity and other factors. EPA does not recommend or endorse specific low-cost monitors. A radon device used to make a decision is different: use a radon measurement device from a qualified laboratory.
The right tool
What does measure radon
A radon test kit or a continuous radon monitor. Active devices need power to run and usually give hourly readings and an average result for the test period. Passive kits are left in place for a set time and then sent to a laboratory. Every radon test should run for at least 48 hours.
What does measure radon
Short-term radon test
Stays in the home two to 90 days, depending on the device, then goes to a lab. The usual first test.
Short-term kitsLong-term radon test
Stays in the home more than 90 days, so it is more likely to show your year-round average.
Long-term kitsContinuous radon monitor
Runs on power and usually gives hourly readings and an average for the test period.
Radon monitorsProfessional radon test
A qualified radon tester, very often a home inspector, places the device and reports the result.
Find a tester
Not sure which? The test chooser picks one for your situation, and many states give kits away: see free and low-cost kits by state.
FAQ
Air quality monitor and radon questions
Can a smart air quality monitor tell me if I have radon?
Only if it has a radon sensor. Check the specifications for radon and a reading in pCi/L or Bq/m3; without them it does not measure radon.
Does a high VOC or particle reading mean radon?
No. A monitor detects only what it is designed for. VOCs and particles are different pollutants from radon, and a reading for them says nothing about radon.
Where should I put a radon monitor?
Test in the lowest lived-in level, at least 20 inches above the floor, away from drafts, high heat, high humidity, and exterior walls. See the placement guide.
Is a consumer radon monitor enough for a home sale?
Check your state's rules first. EPA recommends that an independent, qualified radon tester do the test for a sale. Our home buyer guide covers the options.