Blair County, PA radon potential

EPA places Blair County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Blair County sits at the 95th percentile nationally for radon potential — above 95 of every 100 rated counties.

Blair County by the numbers

Blair County, Pennsylvania is home to about 120,269 people across 525.067 square miles. Population density there runs about 229 people per square mile. Within its own EPA zone, Blair County is bigger by population than 85% of the counties that share it. EPA's geology-based Region 3 groups Blair County with 244 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Blair County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Blair County specifically.

Next steps for a home in Blair County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Pennsylvania's state radon program

For Blair County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Blair County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Blair County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Blair County carries, the zone explainer covers what it does and doesn't tell you about any one house.