Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Blair County, Pennsylvania
EPA puts Blair County in Zone 1, its highest radon zone, and high results are common there: 42.0% of the 424 radon tests reported to CDC (2020) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
42.0%
11.7 pts above PA
- Blair
- 42.0%
- PA
- 30.3%
424 tests, 2020
Median result
3.2pCi/L
Below action level
- Blair
- 3.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2020
Tests reported
424
31st of 63 by tests
- Blair
- 424
- Montgomery
- 10,508
Reported to CDC before any fix, 2020
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in PA
26 of 63
Middle half
- Blair
- 42.0%
- Perry
- 57.7%
By share, of 63 with 30+ tests
Read a result for Blair County
Starts at Blair County's median, 3.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.2 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Blair County's median reported result, 2020.
The data
Blair County, At a glance
Blair County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Blair County in
USGS geologic potential: High across 92% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Blair County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 45.2% |
| 2015 | 39.4% |
| 2016 | 44.0% |
| 2017 | 45.7% |
| 2018 | 42.1% |
| 2019 | 45.7% |
| 2020 | 42.0% |
2020: 42.0%. Across these years the share ran from 39.4% to 45.7%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 424 tests reported to CDC for Blair County over 2020, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).
Blair County, Compared
Blair County radon figures, compared
Calculated by Radon411In Blair County, about 4 in 10 reported tests in 2020 (178 of 424) were at or above EPA's action level. Against the national pool of 25.5%, the gap is 16.5 points higher. Across 67 Pennsylvania counties pooled together, 30.3% of tests reached that level, so Blair County runs 11.7 points above its state.
Of 5 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 39.3% (Centre County) to 54.0% (Huntingdon County). By share, Blair County is 26th of 63 Pennsylvania counties with 30 or more tests for the same period.
Year by year, 2014 opened at 45.2% and 2020 closed at 42.0% (down 3.2 points), with 2017 the high at 45.7%. Half the tests came in under 3.2 pCi/L and half over it; the single highest reached 51.2 pCi/L. Below the action level, 143 tests (33.7%) came in under 2 pCi/L, against 44.3% statewide, and 103 tests (24.3%) fell between 2 and 4, against 25.4% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 42.0% share point the same way here. USGS geology rates 92% of the county's land high radon potential.
The busiest year on file was 2016, with 602 tests reported; the quietest, 2020, had 424.
Blair CountyPennsylvania, pooled
42.0% % of tests30.3% % of tests
| Year | Tests | Blair County, at or above 4 pCi/L | Pennsylvania, pooled |
|---|---|---|---|
| 2014 | 511 | 45.2% | 36.1% |
| 2015 | 548 | 39.4% | 37.8% |
| 2016 | 602 | 44.0% | 34.4% |
| 2017 | 586 | 45.7% | 35.1% |
| 2018 | 442 | 42.1% | 30.5% |
| 2019 | 466 | 45.7% | 31.4% |
| 2020 | 424 | 42.0% | 30.3% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Blair County, State data
Pennsylvania's own radon test data
MeasuredWhat Pennsylvania's own agencies publish about radon tests in Blair County, with their period. These are not CDC's figures and are never added to them.
MeasuredState figures, not CDC's
What Pennsylvania DEP reports for the ZIP codes in Blair County
Pennsylvania DEP publishes its figures by ZIP code, not by county. These are the 20 ZIP codes that lie wholly or partly in Blair County, each with the state's own figures for it. Period: Period not stated by DEP.
| ZIP code | What the state reports |
|---|---|
| 15946 | Basement: average 6.9 pCi/L, 226 tests; First floor: average 2.0 pCi/L, 53 tests |
| 16601 | Basement: average 5.2 pCi/L, 2,322 tests; First floor: average 3.0 pCi/L, 246 tests |
| 16602 | Basement: average 6.6 pCi/L, 3,222 tests; First floor: average 2.7 pCi/L, 223 tests |
| 16613 | Basement: average 11.4 pCi/L, 83 tests; First floor: figures not shown |
| 16617 | Basement: average 4.7 pCi/L, 191 tests; First floor: figures not shown |
| 16625 | Basement: average 8.3 pCi/L, 94 tests; First floor: figures not shown |
| 16631 | Basement: figures not shown |
| 16635 | Basement: average 7.4 pCi/L, 1,836 tests; First floor: average 3.3 pCi/L, 114 tests |
| 16636 | Basement: average 15.9 pCi/L, 45 tests; First floor: figures not shown |
| 16637 | Basement: average 5.8 pCi/L, 55 tests; First floor: figures not shown |
| 16641 | Basement: average 6.9 pCi/L, 104 tests; First floor: figures not shown |
| 16648 | Basement: average 6.0 pCi/L, 3,196 tests; First floor: average 3.0 pCi/L, 168 tests |
| 16655 | Basement: average 7.8 pCi/L, 41 tests; First floor: figures not shown |
| 16662 | Basement: average 10.5 pCi/L, 401 tests; First floor: average 5.0 pCi/L, 36 tests |
| 16665 | Basement: figures not shown; First floor: figures not shown |
| 16673 | Basement: average 10.0 pCi/L, 408 tests; First floor: average 4.9 pCi/L, 46 tests |
| 16682 | Basement: figures not shown |
| 16684 | Basement: figures not shown |
| 16686 | Basement: average 8.2 pCi/L, 869 tests; First floor: average 3.0 pCi/L, 103 tests |
| 16693 | Basement: average 9.1 pCi/L, 166 tests; First floor: figures not shown |
- DEP's report gives the number of tests, the highest result and the average result for each floor tested; it states no period.
- DEP says the smartest thing to do is to test your home for radon, no matter where you live.
- A ZIP code that crosses the county line is listed whole; its figures cover all of it.
Measured: Pennsylvania DEP data, Period not stated by DEP.
Blair County, Geology
The ground under Blair County
PredictedMost of the ground under Blair County is one class on USGS's geologic map: 91.8% of its land is high radon potential, with 8.2% moderate. The map puts 91.8% of Blair County in the area it calls Appalachian Mountain Section and 8.2% in Allegheny Mountain Section. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Appalachian Mountain Section | Paleozoic sandstone, shale, and limestone. | High | 12 | 91.8% |
| Allegheny Mountain Section | Pennsylvanian sandstone, siltstone, shale, limestone, coal. | Moderate | 11 | 8.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Blair County beside the ground around it
Blair County has more high-potential ground than Pennsylvania as a whole: 91.8% of its land against 70.4%. Of the 5 counties that border it, 2 have more high-potential ground, Huntingdon County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Blair County, Local resources
Radon testing and mitigation in Blair County
Listed radon businesses with an address in Blair County:
- Radon DivisionRadon Division, run by Department of Environmental Protection, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Pennsylvania.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Through an EPA-funded program, hospitals give parents of newborn children a packet of information which includes a coupon for a free radon test kit from the DEP.
- Compare kits
- Professionals in Pennsylvania151 professionals are listed in Pennsylvania.
Listed radon professionals by town: Altoona
What Pennsylvania's program says
- Phone
- 800-237-2366
- Licensing of radon professionals
The Radon Certification Act requires DEP to establish by regulation, a certification program for persons conducting radon gas and radon progeny testing, laboratory analysis and mitigation of radon contamination in buildings.
What it means
Blair County, Questions
Questions about radon in Blair County
Are radon levels high in Blair County?
In 2020, 42.0% of the radon tests reported to CDC for Blair County, Pennsylvania were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.2 pCi/L. Of 63 Pennsylvania counties with 30 or more tests for the same period, 25 reported a higher share; pooled, the state comes to 30.3%.
Which counties border Blair County?
Blair County borders 5 counties: Huntingdon County, Cambria County, Clearfield County, Bedford County and Centre County.
Products
Blair County, Products
Testing a home in Blair County
In Blair County, 42.0% of 424 tests reported to CDC in 2020 reached 4 pCi/L, against 30.3% pooled across Pennsylvania. In Zone 1 the year-round level in Blair County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
Monitor
RadonPro Wi-Fi radon monitor with a built-in Geiger counter
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Blair County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Blair County
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Blair County, Bordering counties
Counties bordering Blair County
Calculated by Radon411- Radon levels in Huntingdon CountyEPA zone 1
54.0%at or above 4 pCi/L
Median 4.5 pCi/L · 100 tests · 12.0 points above Blair County
- Radon levels in Bedford CountyEPA zone 1
47.8%at or above 4 pCi/L
Median 3.8 pCi/L · 69 tests · 5.8 points above Blair County
- Radon levels in Clearfield CountyEPA zone 1
47.5%at or above 4 pCi/L
Median 3.6 pCi/L · 394 tests · 5.5 points above Blair County
- Radon levels in Cambria CountyEPA zone 2
44.7%at or above 4 pCi/L
Median 3.3 pCi/L · 329 tests · 2.7 points above Blair County
- Radon levels in Centre CountyEPA zone 1
39.3%at or above 4 pCi/L
Median 2.3 pCi/L · 670 tests · 2.7 points below Blair County
Blair County, Cities and towns
Cities and towns in Blair County
About 119,541 people live in Blair County by the Census Bureau's estimate for July 1, 2025, 3,126 fewer than in 2020 (−2.5%). That works out to 228 people per square mile of land. Its largest town, Altoona, has 42,347 residents, 35.4% of the total. Reported testing is thin here: 424 tests over 2020, or 3.5 for every 1,000 residents (2025 estimate), where Pennsylvania as a whole comes to 7.2.
From Altoona to Newry, CDC publishes no figure by town: each reads Blair County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Altoona | 42,347 | −3.5% | 35.4% |
| Hollidaysburg | 5,470 | −2.3% | 4.6% |
| Tyrone | 5,226 | −3.6% | 4.4% |
| Roaring Spring | 2,280 | −3.8% | 1.9% |
| Martinsburg | 1,811 | −3.1% | 1.5% |
| Bellwood | 1,748 | −3.7% | 1.5% |
| Duncansville | 1,207 | −3.6% | 1.0% |
| Williamsburg | 1,196 | −2.8% | 1.0% |
| Tunnelhillextends beyond Blair County | 302 | −3.8% | Counted whole |
| Newry | 221 | −4.3% | 0.2% |
10 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Blair County is counted whole, so it has no share.
Blair County, Homes
Homes in Blair County
Of Blair County's 55,788 homes, 72% are detached houses, against 57% across Pennsylvania; 9% are in buildings of five or more homes. The homes are older than Pennsylvania's as a whole: half were built before 1957 (1965 for Pennsylvania), and 53% date from before 1960. 72% of occupied homes are lived in by their owner (Pennsylvania: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Blair County | Pennsylvania |
|---|---|---|
| Housing units | 55,788 | 5,779,663 |
| Detached houses | 72% | 57% |
| In buildings of 5 or more | 9% | 13% |
| Mobile homes | 7% | 4% |
| Built before 1960 | 53% | 45% |
| Built since 2000 | 9% | 14% |
| Middle year built | 1957 | 1965 |
| Owner-occupied | 72% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.