Sample Report · Demonstration Data
Radon in Air
Environmental Laboratory Services · Boise, Idaho
The headline finding
This home measured 4.3 pCi/L — modestly above the EPA action level of 4.0 pCi/L. A result this close to the threshold is among the most common we see, and one of the most reliably reduced. The margin is small, three-tenths of a picocurie, and the remedy is well established.
— Dr. Mark L. Arvin, Chief Science Officer
Mitigation is recommended — and a result this close to the threshold is commonly and effectively reduced.
Most professionally mitigated homes settle well under 2.0 pCi/L. The next steps below are the proven path from this result to a verified, lower number.
Low. Below the WHO reference level; routine periodic re-testing is sufficient.
Consider action. Above the WHO reference but below the EPA action level; reduction is worth weighing.
Mitigation recommended. At or above the EPA action level — this home falls here at 4.3.
The measurement, against standards
| Measurement | Result | Reference / Standard | Status | |
|---|---|---|---|---|
| Radon-222 concentration Elevated Measured value, this test window | 4.3pCi/L | EPA action 4.0 · U.S. action level | Above | |
| Margin vs. WHO reference World Health Organization guideline (2.0) | +2.3pCi/L | WHO ref 2.0 · International guideline | Above ref | |
| Margin vs. EPA action level Distance above the U.S. action threshold | +0.3pCi/L | EPA action 4.0 · U.S. action level | Exceeds |
What this means for your home
The EPA identifies radon as the second-leading cause of lung cancer in the United States and recommends mitigation at or above 4.0 pCi/L. I want to be clear and reassuring on one point: a result this close to the threshold is among the most common findings we see, and it is one of the most reliably and effectively reduced. The margin here is small — three-tenths of a picocurie — and the remedy is well established.
Radon enters a home from the soil and rock beneath it, so concentrations vary with season, weather, and how the house is operated. This measurement was taken under closed-house conditions, the standard protocol designed to capture a representative worst-case for the lowest livable level. The recommendations below are the proven path from a result like this to a verified, lower number.
Recommended Next Steps
Retain a contractor certified by the NRPP or NRSB to install an active sub-slab depressurization system. This is the standard, highly effective approach for a home in this range.
After the system has run for 24 or more hours, perform a confirmation measurement to verify the level is reduced below 4.0 pCi/L. Most systems achieve well under 2.0 pCi/L.
Re-measure on a roughly two-year cycle, and again after any major foundation or HVAC change, since both can alter how soil gas moves into the home.
About this test
Method
Short-term measurement following the U.S. EPA protocol, using an activated-charcoal canister deployed for 96 hours under closed-house conditions in the lowest livable level. Analysis was performed by a laboratory using an NRPP-listed device.
What the unit means
Results are expressed in picocuries per liter (pCi/L), a measure of the radioactive activity of radon-222 in indoor air. The EPA action level is 4.0 pCi/L; the WHO reference level is 2.0 pCi/L.
What this test shows
A representative snapshot of radon concentration in the tested area during the deployment window, suitable for deciding whether mitigation is warranted under EPA guidance.
What it does not show
It does not measure year-round average exposure, conditions in untested areas of the home, or any health outcome. Radon levels fluctuate; a single short-term result is a screening measurement, not a continuous record.