
ANSI/AARST MAH-2019: Protocol For Conducting Measurements Of Radon And Radon Decay Products In Homes offers the best practices in measuring a life-threatening issue.
The Dangers of Radon in the Home
Radon is the leading cause of lung cancer among nonsmokers. Naturally released in rock, soil, and water, radon gas is radioactive but odorless and invisible. As it is found in every state, the U.S. Environmental Protection Agency (EPA) and Surgeon General recommend fixing homes with radon levels at or above 4 pCi/L. The EPA also recommends to consider fixing homes with radon levels between 2 pCi/L and 4 pCi/L.
Radon can build up in any home—whether it is old or new or well-sealed or drafty. Because of the potential threat of this dangerous gas, there is a crucial need to test and measure it.
The ANSI/AARST MAH-2019 American National Standard
As for how to conduct these tests, ANSI/AARST MAH-2019 offers a great deal of guidance. It outlines the test protocols, as well as where to test, conditions and rooms of the home for testing, actions based on test results, and testing after radon mitigation, among numerous other topics of interest.

ANSI/AARST MAH-2019 is applicable for more than just professionals. In fact, the standard can be used by homeowners, professionals, and any other party seeking to determine if radon mitigation is necessary for real estate or non-real-estate purpose. Sections 1-7 are directed at anyone conducting radon tests, while sections 8 and 9 of ANSI/AARST MAH-2019 are for use when conducting radon tests as part of professional services.
Please note that ANSI/AARST MAH-2019 does not address all technical aspects of measurement devices, quality assurance, or techniques to identify radon in water supplies, building materials, or in relation to the handling of radioactive materials.
Changes to ANSI/AARST MAH-2019
This standard was first published in 2005, and its previous edition, which was published in 2014, built upon protocols that were developed by EPA’s “A Citizen’s Guide to Radon” and “Home Buyer’s and Seller’s Guide to Radon.”
Similarly, ANSI/AARST MAH-2019 contains numerous updates from the 2014 edition. Specifically, it harmonizes its structure with recent revisions of other ANSI/AARST measurement standards and clarifies the difference between “guidance and mandatory requirements.” Furthermore, the new edition has improved clarity for test durations and locations, how to handle test results that disagree, and professional requirements for qualification, onsite documentation, and reporting. In addition, companion guidance now includes criteria for general inspection of installed mitigation systems.
ANSI/AARST MAH-2019: Protocol For Conducting Measurements Of Radon And Radon Decay Products In Homes is available on the ANSI Webstore.