Radon Testing & Mitigation in O’Fallon, IL

In O’Fallon, IL, Air Sense Environmental tests homes for radon, installs radon mitigation systems, tests indoor air quality and encapsulates crawl spaces. Every radon job in St. Clair County is measured against the EPA action level of 4.0 pCi/L, and the team is NRPP-certified and IEMA-licensed (#RNM20232346).

Is radon a problem in O’Fallon, IL?

Yes. St. Clair County is in EPA Radon Zone 2, where the predicted average indoor radon level is 2 to 4 pCi/L, and individual O’Fallon homes routinely test well above the 4.0 pCi/L action level. The Illinois Department of Public Health reports that about 41 percent of Illinois homes tested have come back at or above 4.0 pCi/L, and Illinois requires radon professionals to hold an IEMA license. O’Fallon, Illinois grew quickly from the 1990s onward around Scott Air Force Base, so most of its housing is newer subdivision construction, which does not exempt it: tight, energy-efficient homes hold radon indoors longer than drafty older ones.

A O’Fallon neighbor’s reading is a signal, not an answer. The soil under one lot, the cracks in one slab and the way one sump pit was sealed decide the number, which is why two similar homes a few doors apart can land on opposite sides of the action level.

Radon testing in O’Fallon, IL

A O’Fallon radon test runs 48 hours under closed-house conditions on a calibrated continuous monitor, and the report shows the hourly data as well as the average. Radon testing in O’Fallon covers how the test works, and the radon testing cost guide holds current pricing.

Radon mitigation in O’Fallon, IL

When a O’Fallon home tests at or above 4.0 pCi/L, the same team designs and installs the radon mitigation system, usually in a single day, and retests to confirm the home is below the action level. See radon mitigation in O’Fallon for the process, documented results and warranty.

Indoor air quality testing in O’Fallon, IL

An indoor air quality assessment for a O’Fallon home logs particulate matter, chemical vapors, CO2, CO and humidity at one-minute intervals for 48 hours or more, so the fix is based on data. Details are on indoor air quality in O’Fallon.

Crawl space encapsulation in O’Fallon, IL

For O’Fallon homes with a crawl space, encapsulation lays a sealed vapor barrier over the soil and walls and adds humidity control, keeping damp air and soil gas out of the rooms above. Read more on the St. Louis crawl space encapsulation page.

Which O’Fallon homes does Air Sense Environmental work on?

The O’Fallon homes the team sees most often:

• 1990s and 2000s two-story homes on poured basements in the subdivisions off Highway 50 and Green Mount Road
• Homes bought and sold on military timelines near Scott Air Force Base, where real estate testing is routine
• Ranch homes in the older core near downtown O’Fallon
• Slab-on-grade villas and townhomes, where the slab itself is the radon pathway

What should O’Fallon homeowners expect?

1. Test first. A 48-hour continuous monitor test gives the number everything else depends on.
2. Read the report together. You get the hourly data and a plain explanation of what it means for the house.
3. Design the fix. If the reading is at or above 4.0 pCi/L, the system is designed around your foundation during a free in-home estimate.
4. Install and verify. Most systems go in within a single day, and a post-mitigation test confirms the result.

About O’Fallon, IL

O’Fallon is a city in St. Clair County, Illinois, United States. The 2020 census listed the population at 32,289. The city is the second largest city in the Metro East region of the St. Louis metropolitan area and Southern Illinois. It sits 5 miles (8.0 km) from Scott Air Force Base and 18 miles (29 km) from Downtown St. Louis. Like its namesake in St. Charles County, Missouri, O’Fallon is part of the St. Louis metro area.

O’Fallon neighborhoods and nearby communities

Air Sense Environmental works across O’Fallon, IL, including downtown O’Fallon, the Highway 50 corridor and the subdivisions between O’Fallon and Scott Air Force Base, in ZIP code 62269. Nearby communities with their own service pages:

• Radon testing and mitigation in Belleville, IL
• Radon testing and mitigation in Fairview Heights, IL
• Radon testing and mitigation in Swansea, IL
• Radon testing and mitigation in Troy, IL
• All Air Sense Environmental service areas

From Our Work