Radon Levels
Radon level of 2 pCi/L: is it safe?
Short answer
A radon level of 2 pCi/L is not high by EPA's standard, but it is the point where EPA starts recommending that you consider a fix. It is above the U.S. indoor average of about 1.3 pCi/L, and no level of radon is safe.
Next step: pick the right test for your home. Which test to use
Key takeaways
- 2 pCi/L is 50 percent of EPA's 4 pCi/L action level.
- In EPA's 2 to 4 pCi/L range: consider fixing.
- EPA estimates the average U.S. home at about 1.3 pCi/L; 2 pCi/L is 1.54 times that.
- Confirm a short-term result with a second test; a long-term test shows the year-round average best.
Where it sits
Is a radon level of 2 pCi/L high?
- 75 Bq/m3
- 2 pCi/L in becquerels per cubic meter, the published figure.
- 50 percent
- Of EPA's 4 pCi/L action level (calculated).
- 1.54 times
- The U.S. indoor average of about 1.3 pCi/L (calculated).
EPA's risk chart has a row for 2 : about 32 lung cancers per 1,000 people who smoked and about 4 per 1,000 who never smoked, over a lifetime of exposure. The advice for the row is to consider fixing between 2 and 4 pCi/L, and reducing radon levels below 2 pCi/L is difficult.
Many homes can be brought to 2 pCi/L or less, and 2 pCi/L or less is a common example of the level a contractor's guarantee might promise. WHO's recommended reference level, 100 , is about 2.7 pCi/L, a little above this reading.
Where 2 pCi/L sits against EPA's and WHO's reference points
Against outdoor air (about 0.4 pCi/L)
5 times the outdoor average (calculated)Against WHO's recommended reference level (100 Bq/m3, 2.7 pCi/L)
Below itEPA's band
In EPA's 2 to 4 pCi/L range: consider fixing
What to do
What to do about a radon level of 2 pCi/L
EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. For a reading of 2 pCi/L, the steps come to this:
Steps for a reading of 2 pCi/L
Confirm the number
A long-term test (more than 90 days) gives a better picture of the year-round level than one short-term result of 2 pCi/L.Weigh a fix
EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Many homes can be brought to 2 pCi/L or less.Get an estimate if you decide to fix
From a qualified contractor credentialed by your state or a national proficiency program.Retest
After any fix, and after renovations or a move to a lower floor.
The full sequence of tests, from a first result to the decision to fix, is drawn on radon testing.
Health risk
The lung cancer risk at 2 pCi/L
EPA's risk chart has a row for 2 pCi/L. It estimates how many people out of 1,000 could get lung cancer if exposed to that level over a lifetime, separately for people who smoked and people who never smoked.
At 2 pCi/L, the chart's lifetime estimate is about 32 in 1,000 people who smoked (6 times the risk of dying from poison), and about 4 in 1,000 who never smoked (the risk of dying from poison). The comparisons in parentheses are the ones EPA prints beside the row.
| Radon level | People who smoked | People who never smoked | What to do |
|---|---|---|---|
| 2 pCi/L (75 Bq/m3) | About 32 in 1,000 | About 4 in 1,000 | Consider fixing between 2 and 4 pCi/L |
These are population estimates from EPA's 2003 assessment of radon risk in homes, not a forecast for any one person. Your own chances depend mostly on how much radon is in your home, how much time you spend there, and whether you smoke or have ever smoked; a former smoker's risk may sit between the two columns. Lung cancer risk is estimated to rise by about 16% per 100 Bq/m3 of long-term average radon.
EPA's whole chart, from outdoor air to 20 pCi/L, is drawn on radon levels.
How sure
How certain is a reading of 2 pCi/L?
One test is a sample of a level that moves. Radon levels tend to vary from day to day and season to season, so a is less likely than a to show the year-round average, and levels can change from hour to hour. A single short-term result of 2 pCi/L is a reading for those days.
Where the test sat matters as much. A test belongs in the lowest lived-in level, and levels are usually higher in basements and rooms in contact with the ground. Testing is the only way to know the radon level in a specific building. Placement and are on radon testing.
With a system
How much a radon system would lower 2 pCi/L
Each technique has a typical reduction range, and with today's technology radon levels in most homes can be reduced to 2 pCi/L or below. Applied to 2 pCi/L, the low end of each range gives the figures below: our arithmetic on the published ranges, not a prediction for your house. Only a test after installation shows what a system achieved.
| Technique | Typical reduction | From 2 pCi/L, about |
|---|---|---|
| Active sub-slab suction (the usual system) | 50 to 99 percent | 1 pCi/L or lower |
| Sump-hole suction | 50 to 99 percent | 1 pCi/L or lower |
| Drain-tile suction | 50 to 99 percent | 1 pCi/L or lower |
| Submembrane suction (crawl spaces) | 50 to 99 percent | 1 pCi/L or lower |
| Passive sub-slab suction (no fan) | 30 to 70 percent | 1.4 to 0.6 pCi/L |
Which technique fits depends on the foundation; see radon mitigation systems, and for cost, radon mitigation cost.
Situations
Where people meet a reading of 2 pCi/L
2 pCi/L in three common situations
2 pCi/L after a mitigation system
As a post-mitigation result, 2.0 pCi/L or below is considered low. Many contractors guarantee to adjust the system to reach a negotiated level, such as 2 pCi/L or less, so a 2 meets that kind of guarantee.2 pCi/L on a first short-term test
Below 4 there is no immediate follow-up to take, but a long-term test shows the year-round average better than a single short-term result.Deciding whether to fix at 2 pCi/L
Reducing radon levels below 2 pCi/L is difficult, which is worth knowing before paying to fix a home that already reads 2. EPA recommends considering a fix in this range; the choice is yours.
Retest
When to retest after 2 pCi/L
2 pCi/L is the exact point where the 2 to 4 pCi/L consider-fixing range begins, so one short-term result cannot say which side of it the home sits on across a year. A long-term test, more than 90 days and through winter if you can, gives the year-round answer. If you do not fix, test again sometime in the future and after any change in how you use the lowest floor.
| When | What to do |
|---|---|
| Sometime in the future | You may want to test again even below 4 pCi/L |
| After a renovation | Major renovations can change the radon level in any home |
| Before using a lower floor | Retest on that level |
| Without a mitigation system | Every 5 years, the Minnesota health department's advice |
| When selling | A buyer may ask for a new test if yours is more than about two years old |
The general answer is on how often should I test for radon.
Questions
Radon level of 2 pCi/L: questions
Is 2 pCi/L of radon safe?
No level is called safe; any radon exposure carries some risk. 2 pCi/L is below the 4 pCi/L action level, but in the 2 to 4 range where EPA recommends considering a fix.
Do I need radon mitigation at 2 pCi/L?
EPA recommends considering it. The decision is yours: weigh a confirmed result, how you use the lowest floor, and the cost.
What is 2 pCi/L in Bq/m3?
It is 75 Bq/m3, the figure EPA prints for it.
Should I buy a house with a radon level of 2 pCi/L?
EPA's guidance for a home under 4 pCi/L is the same whoever owns it: consider a fix from 2 pCi/L. Check that the test was in the lowest level you will use; a buyer may live in a lower area than the seller tested.
Is 2 pCi/L in a basement different from upstairs?
Usually the basement reads higher. Levels are usually highest in basements and rooms in contact with the ground, though considerable levels can occur above the ground floor too. A test belongs in the lowest lived-in level.
How long should I wait to retest after 2 pCi/L?
There is no fixed interval below 4 pCi/L; you may want to test again sometime in the future, and after renovations or a move to a lower floor.
Is 2 pCi/L the same as the WHO level?
No. WHO recommends national reference levels of 100 Bq/m3, about 2.7 pCi/L, where possible: a little above 2 pCi/L, which EPA prints as 75 Bq/m3.