1. What is the ‘acceptable’ level of radon?
The US EPA has established the “action level” for deciding when you need to “do something” about the radon in your home, school, or work place is 4 pCi/l. pCi/l= pico curies per liter, the most popular method of reporting radon levels. For those interested in the numbers, a pico curie is 0.000,000,000,001 (one-trillionth) of a Curie, an international measurement unit of radioactivity. One pCi/l means that in one liter of air there will be 2.2 radioactive disintegrations each minute. For example, at 4 pCi/l there will be approximately 12,672 radioactive disintegrations in one liter of air, during a 24-hour period.
4 pCi/l is the level accepted by most states and US territories, except for New Jersey. New Jersey’s Department of Environmental Protections has established 2 pCi/l as the acceptable action level in their state.
In other countries, the action level ranges from 150 Bq m3, which is slightly less than 4 pCi/l, to no limit or preset action level. For example, in Canada the suggested action level is 200 Bq m3. Bq=becquerels is an international method of measuring radiation.
2. What do you do when you find high radon levels in your home?
First, have you re-tested to confirm that the radon levels are actually too high? (Do you have an average of over 4 pCi/l from the results of two or more short-term tests or from one long-term test of 90 days or more?)
3. What are the advantages or disadvantages to having a radon mitigation system?
If the system is installed correctly and it is operating properly, the primary advantage is that you will have lower in-home radon levels.
Depending on the type of mitigation system, a secondary advantage is a much lower level of humidity (dampness) inside the building, especially in houses with basements or slab-on-grade floors. If the system is an active “sub-slab-suction” design or has incorporated a vapor barrier over the bare soil, then reduced humidity may occur. In many cases, we have heard of folks getting rid of their dehumidifier after seeing how dry the basement became after switching on their mitigation system.
One of the disadvantages is that you will pay a small energy penalty with an active design because of the energy required to run the small fan. Most will only draw about 50 watts. There is also a small loss of inside (conditioned) air that you may have paid to heat or cool. In poor installations, you may be able to hear the fan running. Fortunately, this complaint is seldom heard and if it is, generally easy to fix.
