Radon Gas: The Invisible Carcinogen
Radon-222 is a naturally occurring, radioactive noble gas produced by the radioactive decay of uranium in soil, bedrock, and groundwater. Odorless, colorless, and tasteless, radon is the leading cause of lung cancer among non-smokers in the United States, responsible for approximately 21,000 deaths annually according to the EPA.
Critical Filtration Reality
Air filters cannot trap radon gas. Because radon is an inert atomic noble gas (atomic number 86), it passes unimpeded through mechanical HEPA fibers and activated carbon beds. Air purifiers only trap the radioactive solid decay particulates (radon progeny: polonium, lead, bismuth), not the source gas itself.
EPA Action Levels & Mitigation Protocol
Radon concentrations are measured in picocuries per liter (pCi/L):
- Below 2.0 pCi/L: Baseline acceptable level (average outdoor air is ~0.4 pCi/L).
- 2.0 to 4.0 pCi/L: Consider mitigation, especially if the home is occupied by children or smokers.
- 4.0 pCi/L and Above: EPA Action Level. Active mitigation is strongly recommended. Install a dedicated sub-slab depressurization system with an inline radon exhaust fan.
About ClariSelect Editorial & Research Standards:
Sizing measurements, static pressure curves, and filtration ratings referenced across our educational guides are compiled from published ANSI/ASHRAE Standard 52.2 engineering data, AHAM AC-1 verified ratings, and manufacturer technical documentation. ClariSelect provides objective editorial research and analysis with zero sponsored placements.