Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Sullivan County, Missouri
EPA puts Sullivan County in Zone 2, its middle radon zone, and only 1 radon test from it is on file with CDC (2022). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
27.2%
Adair County
- Adair
- 27.2%
- Linn
- 18.9%
2 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
18.9%
Linn County, 23 miles
- Linn
- 18.9%
- Missouri
- 30.6%
Share at 4+ pCi/L, 37 tests, 2008 to 2017
Ground above low
100.0%
5.8 pts above Missouri
- Sullivan
- 100.0%
- Missouri
- 94.2%
Share of land USGS rates moderate or high potential
Tests reported
6
Too few for a share
- Sullivan
- 6
- Needed
- 30
2008 to 2017, laboratory
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Sullivan County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
Sullivan County, At a glance
Sullivan County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Sullivan County is a
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 Sullivan County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 100.0% |
| 2015 | 0.0% |
| 2022 | 0.0% |
2022: 0.0%. Across these years the share ran from 0.0% to 100.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 1 test was reported to CDC for Sullivan County over 2022, 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: 2022. Measured data period: 2005 to 2022 (every CDC figure on file).
Sullivan County, Compared
Sullivan County radon figures, compared
Calculated by Radon411CDC's largest figure for Sullivan County rests on 6 tests over the 2008 to 2017 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 16.7 points and no rank or comparison is drawn from it. Results reached as high as 39.5 pCi/L, with a middle value of 1.4 pCi/L.
Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Adair County reported the largest share at or above 4 pCi/L, 27.2%, and Linn County the smallest, 18.9%. Farther out, Livingston County (38 miles away) at 22.4%, Macon County (39 miles away) at 19.4% and Daviess County (49 miles away) at 26.7% have figures too. Pooled across 115 Missouri counties, 30.6% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Atchison County reported the highest share (69.9%) and Vernon County the lowest (8.8%). EPA's 1993 map puts Sullivan County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Sullivan County, Geology
The ground under Sullivan County
PredictedUSGS's geologic map puts all of Sullivan 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).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Dissected Till Plains | Till-covered Pennsylvanian sandstone, shale, and limestone. | Moderate | 11 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Sullivan County beside the ground around it
Across Missouri 8.2% of the land is rated high; none of Sullivan County's is. Of the 5 counties that border it, none has as large a share of moderate-potential ground; Adair County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Sullivan County, Local resources
Radon testing and mitigation in Sullivan County
- Missouri Radon ProgramMissouri Radon Program, run by Missouri Department of Health and Senior Services, offers free or discounted test kits, and answers questions about testing and mitigation in Missouri.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Free radon test kits are available for Missouri residents (limit one per household).
- Compare kits
- Professionals in Missouri27 professionals are listed in Missouri.
What Missouri's program says
- Phone
- 573-751-6102
- radon@health.mo.gov
What it means
Sullivan County, Questions
Questions about radon in Sullivan County
Are radon levels high in Sullivan County?
In 2022, 0.0% of the radon tests reported to CDC for Sullivan County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Adair County reported the largest share at or above 4 pCi/L, 27.2%, and Linn County the smallest, 18.9%.
Which counties border Sullivan County?
Sullivan County borders 5 counties: Linn County, Putnam County, Grundy County, Adair County and Mercer County.
Products
Sullivan County, Products
Testing a home in Sullivan County
No CDC figure names Sullivan County; the nearest county with one, Linn County (23 miles away), reported 18.9% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Sullivan County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
MonitorAEGTEST
HOUND-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Sullivan County, Bordering counties
Counties bordering Sullivan County
Calculated by Radon411- Radon levels in Grundy CountyEPA zone 2
37.0%at or above 4 pCi/L
Median 2.8 pCi/L · 27 tests
- Radon levels in Putnam CountyEPA zone 2
33.3%at or above 4 pCi/L
Median 1.8 pCi/L · 9 tests
- Radon levels in Mercer CountyEPA zone 2
27.3%at or above 4 pCi/L
Median 1.7 pCi/L · 11 tests
- Radon levels in Adair CountyEPA zone 2
27.2%at or above 4 pCi/L
Median 1.8 pCi/L · 92 tests
- Radon levels in Linn CountyEPA zone 2
18.9%at or above 4 pCi/L
Median 1.8 pCi/L · 37 tests
Sullivan County, Cities and towns
Cities and towns in Sullivan County
About 5,738 people live in Sullivan County by the Census Bureau's estimate for July 1, 2025, 247 fewer than in 2020 (−4.1%). Spread over its land, that is 8.9 people to the square mile. Its largest town, Milan, has 1,742 residents, 30.4% of the total. Reported testing is thin here: 6 tests over 2008 to 2017, or 1.0 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 9.3.
From Milan to Osgood, CDC publishes no figure by town: each reads Sullivan County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Milan | 1,742 | −4.2% | 30.4% |
| Green City | 570 | −5.0% | 9.9% |
| Browningextends beyond Sullivan County | 216 | −0.9% | Counted whole |
| Greencastle | 211 | −3.7% | 3.7% |
| Newtown | 110 | −5.2% | 1.9% |
| Humphreys | 88 | −4.3% | 1.5% |
| Harris | 59 | −4.8% | 1.0% |
| Pollock | 45 | −4.3% | 0.8% |
| Osgood | 23 | −4.2% | 0.4% |
9 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 Sullivan County is counted whole, so it has no share.
Sullivan County, Homes
Homes in Sullivan County
Sullivan County is a place of houses on their own lots: 76% of its 3,032 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 44% date from before 1960. 74% of occupied homes are lived in by their owner (Missouri: 68%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Sullivan County | Missouri |
|---|---|---|
| Housing units | 3,032 | 2,809,501 |
| Detached houses | 76% | 70% |
| In buildings of 5 or more | 3% | 13% |
| Mobile homes | 9% | 5% |
| Built before 1960 | 44% | 28% |
| Built since 2000 | 12% | 21% |
| Middle year built | 1965 | 1978 |
| Owner-occupied | 74% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.