As a result , the highest levels of radon tend to be found in basements or lower levels . Ventilation has a significant effect on how much radon is in a home , as does weather and the time of year , with radon levels highest in the winter and lowest in the summer .
At high , sustained concentrations , the gas can have severe impacts on human health . The EPA has identified indoor radon as the second leading cause of lung cancer in the U . S . The agency estimates that 21,000 people in the country die every year because of radon , although some scientists dispute the figure .
“ I would not want to be living with radon ,” said Berquist . “ It just doesn ’ t make sense to be breathing a radioactive gas .”
The 4 picocurie per liter action limit set by EPA is intended to serve as a trigger for homeowners to take action to reduce the amount of radon in their houses . But Paris also said the standard is “ pretty conservative ” and assumes that a person is exposed to that level for 8 to 12 hours a day over 70 years .
Four picocuries per liter “ is certainly enough to be concerned about , but it ’ s not going to mean people drop over dead of lung cancer tomorrow ,” he said . “ There ’ s no reason to be alarmed for the levels they ’ ve found in Williamsburg .”
‘ The only way to know is to test ’
For policymakers , residential radon has proved a particularly thorny problem because of how variable levels can be depending on home location and design .
As a result , health officials say testing is the best way to identify any issues . The Virginia Department of Health offers Virginia residents radon testing kits for $ 3 , and residents can also hire a professional , who under Virginia law must be certified by either the National Radon Safety Board or National Radon Proficiency Program to run tests .
“ The only way to know is to test ,” said Paris .
Real estate transactions have typically been popular times to run tests , but no state requires that they be done at the time of sale . ( In Virginia , all new school buildings , however , must be tested for radon by law .) Nor does Virginia require any of its roughly 400 radon testing professionals to report their results to the state : Paris asks for testing data to be shared with VDH on a voluntary basis every six months but said only about 20 to 40 percent choose to do so .