Why did my radon status change from Good to Fair?
If you are a US-based Airthings customer, you may have noticed that your radon reading recently changed from Good (green) to Fair (orange), even though your actual radon level has not changed. This is expected and is the result of an update we made to the default radon thresholds for US accounts.
What changed?
In August 2026 we updated the boundary between Good and Fair for US customers from 2.7 pCi/L to 2.0 pCi/L. The Poor threshold remains unchanged at 4.0 pCi/L.
Rating | Previous threshold | New threshold (EPA-aligned) |
🟢 Good | Below 2.7 pCi/L | Below 2.0 pCi/L |
🟡 Fair | 2.7 - 4.0 pCi/L | 2.0 - 4.0 pCi/L |
🔴 Poor | 4.0 pCi/L or above | 4.0 pCi/L or above (unchanged) |
If your radon level is between 2.0 and 2.7 pCi/L, your status will now show as Fair (🟡) instead of Good (🟢).
Your actual measured radon level has not changed.
Why did we make this change?
We made this update to align the Airthings app with the guidance of the U.S. Environmental Protection Agency (EPA), the governmental reference for radon in the United States.
The EPA recommends that homeowners take action to fix their home when radon levels reach 4.0 pCi/L or higher, and also recommends that homeowners consider fixing their home when levels are between 2.0 and 4.0 pCi/L. Our new Fair range now matches this EPA recommendation directly.
The previous Good/Fair boundary of 2.7 pCi/L was based on the World Health Organization (WHO) reference level of 100 Bq/m³ (which converts to approximately 2.7 pCi/L). While that value is used internationally, the EPA is the authoritative reference for the US market, and we believe US customers are best served when our app reflects the standard that home inspectors, real-estate professionals, and public health agencies in the US use.
Does this mean my home is less safe than before?
No. Your radon level has not changed.
Only the way we categorize it has been updated to match official US guidance. If your level is between 2.0 and 2.7 pCi/L, the EPA considers this a range where you may want to consider taking steps to reduce radon, but it is not an emergency.
Can I set my own thresholds?
Yes. If you prefer different threshold values, you can customize them in the Airthings app. Go to Settings > Thresholds and adjust the values to your preference. You can also tap Reset to default at any time to return to the recommended regional defaults. See our guide: How to customize thresholds.
Where can I learn more about EPA radon guidance?
The EPA provides detailed information on radon action levels on their website: What is EPA's Action Level for Radon?