Radon Risk Chart & Radon Levels Map of VA
March 2023
Radon risk charts and state radon zone maps are tools used to estimate the risk of developing lung cancer due to exposure to radon gas. Radon is a naturally occurring radioactive gas that can seep into buildings from the ground. When people breathe in radon gas, it can damage the cells in their lungs, increasing the risk of lung cancer.
Virginia Radon Zone Map
View radon level maps for all states
Disclaimer:
EPA produced a national radon risk map in 1994. The Virginia map shown above was part of this effort. The map was based on a very limited number of radon test results, existing knowledge of surface geological features/layers and measurements of background radiation. EPA currently has no plans to revise this map. This map was never intended to be used for predictive purposes, but only to provide a rough estimate of the chances of encountering high indoor radon levels in a particular jurisdiction. The only way to know if a particular home has a radon problem is to test for it. EPA & VDH recommend that all homes be tested for radon – especially those being purchased.
Generally in Virginia, the closer you get to the ocean the lower the odds of encountering high radon levels, but this is not a guarantee that high radon levels will never be found in these areas. High radon test results have been found in every Virginia County – including all of those designated as “low risk”. High radon levels in these areas may result when homes are built over small Uranium deposits, non-native fill material or when the foundation is cut into valleys or hillsides where they may encounter deeper geologic layers that are high in radon source material.
Known inaccuracies on the EPA Virginia Risk Map:
The conclusions below are based on additional radon test results accumulated by VDH since 1994:
- Loudoun County should be designated as high risk – not moderate.
- The “low risk” counties along the I-95 corridor that border high risk jurisdictions to their west (ex. Henrico, Hanover, Richmond City, Caroline, King George) should be designated as moderate risk.
- Many homes built in the Williamsburg area at low elevations and/or cut into river valleys have shown high radon test results. See this article for more details: William & Mary radon study.
Radon Health Effects
Elevated levels of indoor radon increases the risk of lung cancer.
Radon is a radioactive gas that occurs naturally in soil and rocks, and it can seep into buildings, particularly those with basements or crawl spaces. Prolonged exposure to elevated levels of radon gas can lead to a number of health problems, including lung cancer.
Like other environmental pollutants, there is some uncertainty about the magnitude of radon health risks. However, today radon is considered the second best studied carcinogen, behind only tobacco. The first radon studies focused on uranium miners, but in recent decades, many case-control residential studies have also been conducted in the United States and many other parts of the world. Most developed countries in the world have now established indoor radon action levels. Most range from 2.7 pCi/L (100 Bq/m3) to 8.1 pCi/L (300 Bq/m3)
As you can see in the chart below, smoking can multiply the radon risk by approximately 10 times. There are currently no conclusive data on whether children are at greater risk than adults from radon.
Your chances of getting lung cancer from radon depend mostly on:
- How much radon is in your home
- The amount of time you spend in your home
- Whether you are a smoker or have ever smoked
Radon Risk If You Smoke*
| Radon Level | If 1,000 people who smoked were exposed to this level over a lifetime…. | The risk of cancer from radon exposure compares to…. | WHAT TO DO: Stop Smoking and… |
|---|---|---|---|
| 20 pCi/L | About 260 people could get lung cancer | 250 times the risk of drowning | Fix your home |
| 10 pCi/L | About 150 people could get lung cancer | 200 times the risk of dying in a home fire | Fix your home |
| 8 pCi/L | About 120 people could get lung cancer | 30 times the risk of dying in a fall | Fix your home |
| 4 pCi/L | About 62 people could get lung cancer | 5 times the risk of dying in an car crash | Fix your home |
| 2 pCi/L | About 32 people could get lung cancer | 6 times the risk of dying from poison | Consider fixing between 2 and 4 pCi/L |
| 1.3 pCi/L | About 20 people could get lung cancer | (Average indoor radon level) | Reducing radon levels below 2 pCi/L is difficult |
| 0.4 pCi/L | (Average outdoor radon level) |
*These lung cancers are in addition to the normal occurrence of lung cancer in the absence of radon. Without any radon exposure, 123 people out of 1,000 male smokers would be expected to get lung cancer; or 58 people out of 1,000 female smokers would be expected to get lung cancer. (BEIR IV Report, National Academy Press, 1988)
Radon Risk If You’ve Never Smoked**
| Radon Level | If 1,000 people who smoked were exposed to this level over a lifetime…. | The risk of cancer from radon exposure compares to…. | WHAT TO DO: Stop Smoking and… |
|---|---|---|---|
| 20 pCi/L | About 36 people could get lung cancer | 250 times the risk of drowning | Fix your home |
| 10 pCi/L | About 18 people could get lung cancer | 200 times the risk of dying in a home fire | Fix your home |
| 8 pCi/L | About 15 people could get lung cancer | 30 times the risk of dying in a fall | Fix your home |
| 4 pCi/L | About 7 people could get lung cancer | 5 times the risk of dying in an car crash | Fix your home |
| 2 pCi/L | About 4 people could get lung cancer | 6 times the risk of dying from poison | Consider fixing between 2 and 4 pCi/L |
| 1.3 pCi/L | About 2 people could get lung cancer | (Average indoor radon level) | Reducing radon levels below 2 pCi/L is difficult |
| 0.4 pCi/L | (Average outdoor radon level) |
**These lung cancers are in addition to the normal occurrence of lung cancer in the absence of radon. Without any radon exposure, 11 people out of 1,000 male smokers would be expected to get lung cancer; or 6 people out of 1,000 female smokers would be expected to get lung cancer (BEIR IV Report, National Academy Press, 1988).