Radon Levels By State

Radon, a stealthy and naturally occurring radioactive gas, is prevalent across the United States, silently contributing to a significant share of lung cancer cases nationwide. With no smell, taste, or color, it quietly infiltrates our homes, originating from the decay of uranium in soil, rock, and water. Prolonged exposure to this silent menace has long-term health implications, making it essential to evaluate and monitor average radon levels in every state.

The U.S. Environmental Protection Agency (EPA) recommends taking action if radon levels exceed 4 pCi/L in homes. To provide a comprehensive overview of radon distribution in the U.S, we've collated data from various states, ranking each according to their average radon level in picocuries per liter (pCi/L), a measure of radioactivity.

• Alaska leads the list as the state with the highest average radon level of 10.7 pCi/L, significantly above the EPA's recommended action level. Following Alaska, South Dakota and Pennsylvania also report alarmingly high radon levels of 9.6 and 8.6 pCi/L, respectively.
• Interestingly, the top ten states with the highest radon levels are a combination of both coastal and inland states, debunking any presumptions of geographical favoritism. 
• On the flip side, Louisiana records the lowest average radon level of 1.1 pCi/L, followed by Mississippi and Florida. It's noteworthy that the three states with the lowest radon levels are all in the Southern U.S.
• From the middle to the lower end of the spectrum, average radon levels remain fairly consistent, hovering around the 4 pCi/L mark. This concentration range includes states like North Carolina, Nevada, and Oregon.

When evaluating the states with the highest average radon levels, Alaska grabs the top spot, with an average of 10.7 pCi/L. In the second position, we have South Dakota, exhibiting a high average radon level of 9.6 pCi/L. Next comes Pennsylvania, with a radon level of 8.6 pCi/L.Following closely, Ohio secures the fourth position with an average radon level of 7.8 pCi/L outperforming the fifth spot, Washington, which sees a 7.5 pCi/L radon level. Montana and Kentucky both present a joint average of 7.4 pCi/L of radon, posing significant health risks to their residents.

Idaho's radon level is not far behind, standing at 7.3 pCi/L and surpassing Colorado's level of 6.8 pCi/L. Lastly, Iowa closes our top ten list, having an average radon level of 6.1 pCi/L which, although lower, still is above the EPA's recommended radon action level.

States with the Highest Radon Levels:

1. Alaska - 10.7 pCi/L
2. South Dakota - 9.6 pCi/L
3. Pennsylvania - 8.6 pCi/L
4. Ohio - 7.8 pCi/L
5. Washington - 7.5 pCi/L
6. Montana - 7.4 pCi/L
7. Kentucky - 7.4 pCi/L
8. Idaho - 7.3 pCi/L
9. Colorado - 6.8 pCi/L
10. Iowa - 6.1 pCi/L