A new map has revealed that up to 25 percent of Americans live in areas where radon levels are considered unsafe by the Environmental Protection Agency (EPA).
Radon is a radioactive gas that has no color, smell or taste. It is present in both indoor and outdoor air everywhere, but there is no known safe level of exposure to this noxious substance.
It comes from the natural decay of uranium, a radioactive element that is found in nearly all soils.
Studies show radon exposure is the second leading cause of lung cancer in the US after smoking, leading to about 21,000 lung cancer deaths each year, according to the EPA.
Now, researchers have identified and mapped areas throughout the US where radon levels are over the EPA’s ‘action level’ of 148 Becquerels per cubic meter (Bq/m³), or the level at which the agency requires regulatory action.
The average outdoor radon concentration is around 15 Bq/m³, or one-tenth that action level.
The Great Plains region appears to have the highest levels, especially around the border between Iowa, Nebraska and South Dakota.
Northern Kansas, central Colorado, central Ohio and central Pennsylvania were also identified as radon hot-spots.
A new map has revealed that up to 25 percent of Americans live in areas where radon levels are considered unsafe by the Environmental Protection Agency (EPA). Locations in red were found to have radon levels up to or above the action level of 148 Bq/m³
Some of these states — particularly those in the upper Midwest — are known to have elevated concentrations of uranium in their soils, which may account for heightened radon levels.
But interestingly, the researchers also found that over 83 million Americans live in homes with radon concentrations over 148 Bq/m³, even though they are in low-radon zones. This highlights the need for more comprehensive surveys, they stated.
The vast majority of radon exposure comes directly from soils. As uranium inside the soil breaks down and releases radon gas, that gas can enter homes and buildings through cracks in the foundation.
Over time, it can accumulate to harmful concentrations in poorly ventilated spaces, the researchers wrote in their report.
Once in the air, radon gas breaks down into tiny radioactive elements known as radon progeny.
These particles can lodge in the lining of the lungs and then give off radiation, damaging lung cells and eventually leading to cancer, according to the American Cancer Society (ACS).
It can take years or even decades to get lung cancer from radon exposure alone. But most radon-related lung cancers develop in people who smoke, as radon exposure compounds their already heightened cancer risk.
According to the EPA, 62 in 1,000 smokers who spent their entire lives exposed to the action level of radon would get lung cancer, while only seven in 1,000 non-smokers would develop the disease.
In all, the study found that 9.7million Americans live in areas with radon levels above 148 Bq/m³ during the winter
During the summer, just 0.12million Americans live in areas with radon concentrations above the action level
Lung cancer is extremely deadly, as it is responsible for about one in five of all cancer deaths in the US, according to the ACS.
In addition to identifying dangerous levels of radon in the Great Plains region, the study highlighted significant variation between radon levels in the winter versus the summer.
‘The highest monthly radon concentrations commonly were found in the winter when the ventilation is lower due to the efforts to conserve energy during the heating season,’ the researchers wrote in their report, published in the journal PNAS.
During these colder months, radon levels were significantly higher in northwestern Kansas, eastern Nebraska and South Dakota, southern Minnesota and all across Iowa and North Dakota.
Scattered locations throughout Montana, Idaho, Wyoming and Colorado also had high radon levels in winter, in addition to significant portions of central Ohio and eastern Pennsylvania.
In all, the study found that 9.7million Americans live in areas with radon levels above 148 Bq/m³ during this season, as opposed to just 120,000 in the summer.
To create these maps, the researchers analyzed six million indoor radon measurements taken around the country between 2001 and 2021.
Lung cancer is an extremely deadly form of cancer, as it is responsible for about one in five of all cancer deaths in the US, according to the ACS (STOCK)
They then used a machine learning model to estimate monthly community-level radon concentrations based on geological, meteorological, architectural and socioeconomic factors.
If radon levels inside your home are above the EPA’s action level, the agency strongly recommends that you seal gaps in your foundation, walls and floors to reduce radon entry into the house, add ventilation to crawl spaces or beneath foundations to prevent radon buildup and take measures to improve indoor air circulation.
But the EPA notes that there is no truly safe level of radon exposure, so it is recommended to fix your home even if levels are detected as low as 75 Bq/m³.
The researchers hope that ‘The high-resolution radon maps can be used by federal and local governments to design, update, and improve the regulations,’ they wrote.
‘Furthermore, the model can be used to assess residential exposure to radon, thus facilitating studies to expand our understanding of radon’s health effects.’
