Frequently Asked Questions

Radon is a radioactive gas that is produced when naturally occurring  uranium, which is present in the ground and rocks all across the globe, breaks down and  forms other elements in a process called radioactive decay. Radon is one link in the decay  chain of uranium. When radon gas decays, it emits radioactive radiation in the form of an  alpha particle. 

Radon is the single largest source of ionizing radiation a person  receives throughout the year. Long-term exposure to radon in buildings is the leading cause  of lung cancer in the general population, second to tobacco use. Radon affects everyone,  and people who smoke tobacco are at significantly higher risk of developing lung cancer  from radon. According to the Environmental Protection Agency (EPA), approximately 21,000  Americans die per year from radon-induced lung cancer. This is greater than residential fires,  electrocutions, carbon monoxide poisonings, and drownings combined. 

According to EPA, approximately 1 in 15  homes (~7%) nationwide have indoor radon levels above the EPA action level. This  percentage varies greatly by state, and can be as high as 5 in 7 homes (~70%) in Iowa. 

Buildings typically have a lower air pressure  indoors than the outdoor air pressure which causes radon in the soil to be pushed into the  building. The radon levels present inside a building are affected by a number of factors  including the amount of radon in the ground, wind, the geology of the area, how the  building was constructed, and water or moisture content in the ground; as well as how the  building is used, such as the use of appliances, exhaust fans, and windows. Radon can also  enter buildings from well water or materials that contain radon. 

It is impossible to predict  which buildings may or may not have elevated indoor radon levels, so the only way to know  if your house has elevated levels of radon is to have it tested. Any building can have  elevated radon levels even when the neighboring buildings all have low radon levels. 

Measuring indoor radon  levels is as important as having functioning fire alarms and carbon monoxide alarms  installed. EPA recommends having a home measured for radon whenever it is bought, or  has significant changes made to its structure or heating and ventilating systems. Homes  should also be tested every 2 years for those with radon mitigation systems installed, or  every 5 years for those without mitigation systems when the previous measurements were  below the action level. 

There are various methods for measuring radon levels, all of  which require specialized equipment. The most common format of radon measurements is a  short-term measurement lasting less than 90 days. These short-term measurements require  special closed-building conditions which must be followed to achieve valid results. Since  radon levels change hourly and daily, 48 hours has been determined to be the minimum 
time required to get a usable average. EPA recommends using a long-term measurement  lasting 12 months to obtain the most accurate radon levels in a building. 

In the United States radon is measured in picoCuries per  liter of air, abbreviated pCi/L. In the rest of the world radon is measured in Becquerels per  cubic meter, abbreviated Bq/m3. 

While no level of ionizing radiation is “safe”, EPA has set  an action level for radon at 4.0 pCi/L, meaning if levels of radon in a building are found at or  above 4.0 pCi/L, then EPA strongly recommends that action be taken to reduce the levels of  radon in the building. EPA also suggests considering taking action if levels are found  between 2.0 - 4.0 pCi/L. The action level of the World Health is 2.7 pCi/L (100 Bq/m3). 

Typical nationwide indoor radon  levels in the United States average 1.3 pCi/L while outdoor levels typically average 0.4 pCi/L.  Iowa has the highest average indoor radon level in the USA at around 8.5 pCi/L, which is  more than double the EPA action level. While many states have significantly lower averages,  any house can have radon above the EPA action level, so it is important to have every house  tested for radon. 

Typical nationwide indoor radon  levels in the United States average 1.3 pCi/L while outdoor levels typically average 0.4 pCi/L.  Iowa has the highest average indoor radon level in the USA at around 8.5 pCi/L, which is  more than double the EPA action level. While many states have significantly lower averages,  any house can have radon above the EPA action level, so it is important to have every house  tested for radon. 

Since radon levels in a building are  caused by numerous factors including rainfall and wind, and the use of heating systems,  radon levels can vary significantly from day to day and from season to season. Some radon  mitigation systems to not keep indoor radon levels below the action level 100% of the time.  In rare circumstances, the indoor radon levels may peak significantly above the action level  during severe weather, so it is important to keep a continual watch on radon levels  throughout the year. 

Airthings offers a selection of consumer  friendly radon monitors which will allow you to monitor the radon levels in your home. This  way you can be sure your radon mitigation system is working properly at all times, especially  during sever weather, and to get warning when your mitigation system may be failing or in  need of a fan replacement.