Northwood News ♦ December 2019

Radon, a Cancer-Causing Radioactive Gas, May Be in Your Home

By Linda S. Perlman

Radon is a colorless, odorless, invisible, cancer-causing gas produced by the natural (radioactive) decay of uranium in soil, rocks, and water.  Radon occurs naturally in nearly all types of soil and radon can get in the air you breathe.  Radon typically moves up through the ground to the air above and then enters homes and other buildings through cracks and other holes in the foundation.

There is no safe level of radon and radon is found in all types of homes and buildings.  Radon gas is heavier than air, so the lower areas of homes and buildings are more affected.  Basements, rooms over concrete slabs, and areas over crawl spaces are the most likely areas of the house to have high radon levels.  Radon generally is not a health risk outdoors because it is diluted in open air.

The adverse health effects of long-term radon exposure are well documented:  breathing air that contains radon can cause lung cancer.  According to the United States Environmental Protection Agency (EPA), radon is estimated to cause approximately 21,000 lung cancer deaths per year.

Montgomery County has high radon levels in its soil and is classified as a Zone 1 (high radon potential) area by the EPA.  Designation as a Zone 1 area means that the predicted average indoor radon level is equal to or greater than the recommended safe amount of 4 pico-Curies per liter (pCi/L).  The amount of radon in the air is measured in pCi/L.  EPA recommends remedial action (i.e., fixing your home) if radon levels are 4 pCi/L or higher.

Your home must be tested for radon to determine if you are at risk from radon.  There are two general ways to test for radon.  Short-term tests remain in your home for two days to 90 days and are the quickest way to measure radon levels.  Long-term devices measure radon levels for 90 days or more.  Long-term tests take day-to-day fluctuations in radon levels into account and are more likely to provide a more accurate year-round average radon level than a short-term test.

Before purchasing a home radon testing device, you should review the Montgomery County Department of Environmental Protection’s list of approved testing devices at montgomerycountymd.gov/green/air/radon.html.  Testing also can be done by radon professionals.

If the results of one long-term test or the average of two short-term tests indicate radon levels of 4 pCi/L or higher, then EPA recommends taking further action to fix your home.  Radon remediation systems can effectively reduce radon levels in homes to 2 pCi/L or lower.  As any level of radon exposure carries some risk of causing lung cancer, you also should consider radon mitigation if the radon level in your home is between 2 pCi/L and 4 pCi/L.

The primary method used to reduce radon is a vent pipe system and fan, which continuously pulls radon from beneath the house and vents it outdoors through a pipe.  The pipe can either run inside or outside the home and discharges outside, away from the windows and openings.  In addition, cracks and openings in the foundation are sealed.  Sealing limits the flow of radon and makes the radon mitigation system more efficient.

A home’s foundation type helps determine the radon mitigation method that will work best.  A radon professional can determine the type of mitigation system to install and may conduct some diagnostic testing.  To find a certified radon contractor, you can contact an independent radon proficiency program, such as the National Radon Proficiency Program (aarst-nrpp.com) or the National Radon Safety Board (nrsb.org).  The EPA’s Consumer’s Guide to Radon Reduction also provides information on selecting a contractor, different types of radon mitigation systems, and other information to help ensure that the radon reduction system is effective and meets your needs.

Montgomery County law now requires radon testing before settlement on the sale of single-family detached homes and townhouses.  The radon test can be done by the seller, buyer, or an independent home inspector or radon-testing professional hired by either the seller or buyer, but both parties must receive a copy of the radon test results.  For more information on the testing requirements for home sales, go to montgomerycountymd.gov/green/air/radon.html and click on “Radon and Buying or Building a Home.”   ■