Radon Unit Converter: Bq/m³ ↔ pCi/L

Radon shows up in two different units depending on which country's information you're reading. Canada and most of the world use becquerels per cubic metre (Bq/m³) — the SI unit. The United States uses picocuries per litre (pCi/L). They measure the same thing; only the scale differs — the conversion is exact: 1 pCi/L = 37 Bq/m³.

How to read a U.S. radon reading in Canadian terms

If you're reading an American guide or looking at a monitor that displays pCi/L, multiply by 37 to get the Canadian Bq/m³ figure. The U.S. EPA "action level" of 4 pCi/L is 148 Bq/m³ — below Canada's guideline. Health Canada's guideline is 200 Bq/m³ (about 5.4 pCi/L), and the World Health Organization's reference level is 100 Bq/m³ (about 2.7 pCi/L). Whatever unit your device or source uses, what matters for a decision is a long-term measurement compared against Health Canada's 200 Bq/m³ guideline.

See what counts as an acceptable radon level in Canada; if your result is high, what to do when your radon level is above 200 Bq/m³; and to measure your own home, the radon test kit.

Frequently asked questions

What is Bq/m³?
Becquerels per cubic metre (Bq/m³) is the SI unit for radon concentration used in Canada and most of the world. One becquerel is one radioactive decay per second in a cubic metre of air. Health Canada's guideline is expressed as 200 Bq/m³.

What is 4 pCi/L in Bq/m³?
4 pCi/L equals 148 Bq/m³ (4 × 37). That is the U.S. EPA action level, which sits below Canada's 200 Bq/m³ guideline.

What does 200 Bq/m³ mean?
200 Bq/m³ (about 5.4 pCi/L) is Health Canada's guideline — the level at which it recommends taking action to reduce radon. It is an action guideline, not a line between acceptable and harmful; there is no radon level free of risk, but the risk is lower below the guideline.