What is the maximum duration allowed for a short-term radon test?

The maximum duration allowed for a short-term radon test is indeed 90 days. Short-term tests are designed to provide quicker results and are typically conducted over a period that can range from a few days up to 90 days in order to gain a reliable assessment of radon levels in a building. Tests lasting longer than 90 days would not categorize as short-term tests but rather as long-term tests, which provide a more comprehensive picture of radon exposure by accounting for variations in radon levels over time. Using a short-term test for radon measurement is particularly useful when immediate remediation decisions are needed or for real estate transactions where prompt results are often desired.