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Radon Levels in Linn County, Missouri

EPA puts Linn County in Zone 2, its middle radon zone, and only 3 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    18.9%

    11.7 pts below MO

    Linn
    18.9%
    Missouri
    30.6%

    37 tests, 2008 to 2017

  • Median result

    1.8pCi/L

    Below action level

    Linn
    1.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    37

    64th of 72 by tests

    Linn
    37
    St. Louis
    17,747

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Missouri

    62 of 72

    Lowest quarter

    Linn
    18.9%
    Atchison
    69.9%

    By share, of 72 with 30+ tests

Read a result for Linn County

Starts at Linn County's median, 1.8 pCi/L

1.8pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 1.8 pCi/L

Below 2 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Linn County's median reported result, 2008 to 2017.

Interpret this reading

The data

Linn County, At a glance

Linn County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Linn County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Linn County, 2023

Share of reported tests at or above 4 pCi/L, by year, Linn County
Share of reported tests at or above 4 pCi/L, by year, Linn County
YearShare of reported tests at or above 4 pCi/L
20140.0%
201540.0%
20160.0%
20170.0%
20190.0%
20200.0%
20210.0%
202240.0%
202333.3%

2023: 33.3%. Across these years the share ran from 0.0% to 40.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 3 tests were reported to CDC for Linn County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.

Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Linn County, Compared

Linn County radon figures, compared

Calculated by Radon411

Linn County's 37 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.8 pCi/L and a maximum of 14.1 pCi/L, and 18.9% reached 4 pCi/L. Missouri as a whole (115 Missouri counties, pooled) comes to 30.6%: 11.7 points higher than here.

The newest figure, in 2023, counts only 3 tests (33.3% at or above 4 pCi/L), too few to compare, so this reading uses the 37-test figure.

Among its state's counties it ranks 62nd of 72 Missouri counties with 30 or more tests for the same period. Statewide for the same period, Atchison County reported the highest share (69.9%) and Vernon County the lowest (8.8%).

Below the action level, 20 tests (54.1%) came in under 2 pCi/L, against 41.2% statewide, and 10 tests (27.0%) fell between 2 and 4, against 28.1% statewide. The busiest year on file was 2015, with 5 tests reported; the quietest, 2020, had 1.

EPA's 1993 zone map puts Linn County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Next door, the shares run from 19.4% in Macon County to 27.2% in Adair County.

Linn County against Missouri, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Linn County
Linn County3718.9%1.8 pCi/LThis county
Missouri, pooled115 counties, pooled58,52530.6%Not pooled+11.7 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+16.8 points
Atchison Countyhighest in the state10369.9%5.6 pCi/L+51.0 points
Vernon Countylowest in the state348.8%0.9 pCi/L−10.1 points
Grundy County, MOborders it2737.0%2.8 pCi/L+18.1 points
Sullivan County, MOborders it633.3%1.4 pCi/L+14.4 points
Adair County, MOborders it9227.2%1.8 pCi/L+8.3 points
Livingston County, MOborders it4922.4%2.1 pCi/L+3.5 points
Macon County, MOborders it3619.4%1.7 pCi/L+0.5 points
Chariton County, MOborders it1513.3%1.7 pCi/L−5.6 points
Where Linn County's reported results fell, 2008 to 2017, laboratory, beside Missouri and the United States
ResultLinn County testsLinn County shareMissouri shareU.S. shareAgainst Missouri
Under 2 pCi/L2054.1%41.2%39.6%+12.9 points
2 to 4 pCi/L1027.0%28.1%24.7%−1.1 points
4 pCi/L and above718.9%30.6%35.7%−11.7 points
Linn County ranked among the 72 Missouri counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Butler County57 of 723321.2%1.9 pCi/L
Morgan County58 of 7212321.1%2.2 pCi/L
Webster County59 of 7210320.4%1.6 pCi/L
Macon County60 of 723619.4%1.7 pCi/L
Texas County61 of 725719.3%1.3 pCi/L
Linn County62 of 723718.9%1.8 pCi/L
Pulaski County63 of 7210718.7%1.3 pCi/L
Randolph County64 of 725817.2%1.8 pCi/L
Miller County65 of 7215416.9%1.9 pCi/L
St. Louis city66 of 721,87316.9%1.9 pCi/L
Osage County67 of 725215.4%1.5 pCi/L
Linn County radon tests by year, against Missouri's pooled share
YearTestsAt or above 4 pCi/LMedianHighestMissouri, pooledChange from the row before
2023333.3%3.4 pCi/L16.0 pCi/L35.7%−6.7 points
2022540.0%1.1 pCi/L6.5 pCi/L40.8%+40.0 points
202120.0%0.8 pCi/L1.1 pCi/L31.8%Level
202010.0%1.1 pCi/L1.1 pCi/L33.2%Level
201910.0%2.3 pCi/L2.3 pCi/L33.5%Level
201710.0%0.2 pCi/L0.2 pCi/L37.0%Level
201610.0%0.9 pCi/L0.9 pCi/L29.8%−40.0 points
2015540.0%1.4 pCi/L9.0 pCi/L27.6%+40.0 points
201410.0%0.6 pCi/L0.6 pCi/L34.4%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Linn County, Geology

The ground under Linn County

Predicted

USGS's geologic map puts all of Linn County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Dissected Till Plains, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Linn County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Dissected Till PlainsTill-covered Pennsylvanian sandstone, shale, and limestone.Moderate11100%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Linn County beside the ground around it

Across Missouri 8.2% of the land is rated high; none of Linn County's is. Of the 6 counties that border it, none has as large a share of moderate-potential ground; Adair County comes nearest at 100%.

Share of land by USGS radon potential: Linn County, the 6 counties bordering it and Missouri
AreaEPA zoneLow potentialModerate potentialHigh potential
Linn CountyZone 2None100%None
Sullivan CountyZone 2None100%None
Livingston CountyZone 2None100%None
Chariton CountyZone 2None100%None
Macon CountyZone 2None100%None
Grundy CountyZone 2None100%None
Adair CountyZone 2None100%None
Missouri115 counties, pooled by land areaVaries5.8%86.0%8.2%

The map rates the ground, not the air in any home.

Local help

Linn County, Local resources

Radon testing and mitigation in Linn County

What Missouri's program says
Phone
573-751-6102
Email
radon@health.mo.gov

What it means

Linn County, Questions

Questions about radon in Linn County

Are radon levels high in Linn County?

In 2023, 33.3% of the radon tests reported to CDC for Linn County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.4 pCi/L. Of 72 Missouri counties with 30 or more tests for the same period, 61 reported a higher share; pooled, the state comes to 30.6%.

Which counties border Linn County?

Linn County borders 6 counties: Sullivan County, Livingston County, Chariton County, Macon County, Grundy County and Adair County.

Products

Linn County, Products

Testing a home in Linn County

In Linn County, 18.9% of 37 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.6% pooled across Missouri. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Linn County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Linn County homes, compared

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Linn County, Bordering counties

Counties bordering Linn County

Calculated by Radon411

Linn County, Cities and towns

Cities and towns in Linn County

Linn County's population has barely moved since 2020: 11,815 residents on July 1, 2025 against 11,854 then, by the Census Bureau's estimates. That works out to 19 people per square mile of land. Its largest town, Brookfield, has 4,083 residents, 34.6% of the total. Reported testing is thin here: 37 tests over 2008 to 2017, or 3.1 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 9.3.

From Brookfield to Purdin, CDC publishes no figure by town: each reads Linn County's.

The cities and towns in Linn County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Brookfield4,083−0.3%34.6%
Marcelineextends beyond Linn County2,116−0.6%Counted whole
Meadville413−0.5%3.5%
Bucklin410−0.5%3.5%
Laclede300−1.0%2.5%
Linneus277−0.4%2.3%
Browningextends beyond Linn County216−0.9%Counted whole
Purdin138−1.4%1.2%

8 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 Linn County is counted whole, so it has no share.

Linn County, Homes

Homes in Linn County

Linn County is a place of houses on their own lots: 85% of its 6,007 homes are detached single-family houses, against 70% across Missouri. The homes are older than Missouri's as a whole: half were built before 1965 (1978 for Missouri), and 42% date from before 1960. Owners live in 79% of the occupied homes (Missouri: 68%), so for most households a test and a fix are their own to order.

Homes in Linn County, Missouri, 2019 to 2023
HomesLinn CountyMissouri
Housing units6,0072,809,501
Detached houses85%70%
In buildings of 5 or more2%13%
Mobile homes7%5%
Built before 196042%28%
Built since 200010%21%
Middle year built19651978
Owner-occupied79%68%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.