Short answer
No. A smoke detector senses smoke as a sign of fire; even an ionization model, which uses a small amount of radioactive americium-241 to do it, does not measure radon. To measure radon you need a radon test kit or a radon monitor.
In brief
What a smoke detector senses
A smoke detector senses smoke as a sign of a possible fire. Like a carbon monoxide alarm, it is an emergency alert device, designed and certified to warn of a potentially life-threatening situation. It is built for smoke, not for radon, an odorless, colorless, radioactive gas from the ground.
| Smoke detector | Radon test or radon monitor | |
|---|---|---|
| What it senses | Smoke, as a sign of fire | Radon gas in the air |
| What it does | Sounds an alarm in an emergency | Measures the radon level over the test period |
| Unit | None: alarm or no alarm | pCi/L or Bq/m3 |
What it senses
- Smoke detector
- Smoke, as a sign of fire
- Radon test or radon monitor
- Radon gas in the air
What it does
- Smoke detector
- Sounds an alarm in an emergency
- Radon test or radon monitor
- Measures the radon level over the test period
Unit
- Smoke detector
- None: alarm or no alarm
- Radon test or radon monitor
- pCi/L or Bq/m3
Americium-241
The radioactive part of an ionization smoke detector
Some smoke detectors do contain radioactive material, which may be where the confusion starts. Ionization smoke detectors use a small amount of radioactive americium-241 to detect smoke: alpha particles from the americium source ionize air molecules, two charged plates create a flow of charged ions, and the alarm triggers when smoke breaks that flow. The americium is a source of radiation inside the detector, not a sensor for radon in the room.
What to do
Keep the smoke detector, add a radon test
Use a smoke detector in your home: it can save your life, and most are certified for a useful life of ten years. A smoke detector does not replace a radon test. Testing is the only way to know whether your family is at risk from radon, and EPA and the Surgeon General recommend testing all homes below the third floor.
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.
Placement
Where each one goes
A smoke detector and a radon test belong in different places. A radon test goes in the lowest lived-in level of the home, at least 20 inches above the floor, away from drafts, high heat, high humidity and exterior walls, and never in a closet, stairway, hallway, crawl space, or a humid enclosed room such as a kitchen, bathroom, laundry room or furnace room.
FAQ
Smoke detector and radon questions
Is there a smoke detector that detects radon?
A device detects radon only if it has a radon sensor and reports pCi/L or Bq/m3. A smoke detector senses smoke; check any combination device's specifications for radon.
Does the americium in my smoke detector give off radon?
No. The americium-241 in an ionization smoke detector is a source of alpha particles used to sense smoke, sealed in foil and ceramic. Radon comes from uranium and radium in the ground beneath a home.
How often should I replace a smoke detector?
Most detectors are certified for a useful life of ten years; check the expiration date when you replace the batteries.