The radon guides.
Ten guides that answer the questions people actually ask about radon: what the EPA zones mean, how to test, how mitigation works, what to disclose when selling, and how bad the risk really is. Each one cites the EPA, CDC, and peer-reviewed studies it draws from, so you can follow any claim back to its source.
EPA Radon Zones explained: what each zone means for your home
Zone 1, 2, and 3 defined directly from EPA-402-R-93-071: what the classification predicts about indoor levels, what it doesn't, and when state data overrides the federal map.
Short-term vs long-term radon testing: which to use when
2–7 day kits vs. 90+ day kits. Trade-offs, the EPA's recommended protocol, when to escalate, and how to read the result against the action level.
Sub-slab depressurization: how mitigation systems actually work
The dominant residential mitigation technique, pulled straight from EPA-402-K-10-005 and ANSI/AARST SGM-SF-2017: fan sizing, piping, exhaust placement, monitoring.
The 10 highest-radon US counties (and what they have in common)
The counties with the highest published indoor radon averages, the geology that drives them, and what residents should do differently.
Radon in well water: how it differs from soil-gas radon
The separate exposure pathway through private wells in granitic terrain. How to test, what 300 vs. 4,000 pCi/L means, and what an aeration unit costs.
Selling a home with high radon: disclosure, mitigation, negotiation
EPA-402-K-13-002 in plain English: what disclosure looks like, who pays for mitigation, how to time the work, and how to price the negotiation.
Radon and lung cancer: what the EPA risk numbers actually say
Table A-1 of EPA-402-R-03-003 decoded: lifetime deaths per 1,000 by exposure level, the BEIR VI dose-response, and the Iowa case-control evidence.
DIY radon testing: the right kit, the right placement, the right time
How to test correctly: kit type, placement, closed-house conditions, season, depth in the home, and how to interpret the lab result.
Radon in apartments and condos: above-grade unit risk
How the soil-gas pathway changes with floor level, ANSI/AARST MS-PMD-2014 measurement protocol, and what a tenant or HOA can actually do.
Radon after a basement remodel: why re-testing matters
Why structural changes can void prior test results, the EPA's retest cadence, and the specific scenarios that warrant a fresh measurement.
Ten guides in, still want a shortcut?
The guides stay free. The $9 PDF compresses the county-relevant fraction of them into one printable page.
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