that’s very interesting, thanks for sharing that.
NH will probably follow suit.
One point of consideration should be that if you read the EPA protocol carefully, 4.0 pCil is not considered “safe”. It is the level that can be economically accomplished through radon mitigation.
Clients often get upset at 4.1. Homeowners think you can keep testing until you get one reading below 4.0 (don’t understand you must average all tests taken). 3.9 is not “safe”.
So remember, anything below 2.0 should not be considered “safe” either. The safest level obtainable is the 0.3 pCi/l outdoor air concentration. Any level above that should be a consideration for mediation or corrective action that will reduce elevated indoor radon levels, such as the lack of combustion air vents for fossil fuel appliances, leaking air duct systems into the unfinished basement or attic space, or other conditions which cause the atmospheric pressure within the house to drop.