True or False: Air conditioning systems that recirculate indoor air may be used during a short-term radon test.

Using air conditioning systems that recirculate indoor air during a short-term radon test is considered acceptable because it is crucial to maintain a stable indoor environment while testing for radon levels. In a short-term test, the objective is to evaluate the radon concentration in the air over a specific period, typically ranging from 2 to 7 days. Air conditioning units help to regulate temperature and humidity, ensuring that the test results are not influenced by external environmental factors.

Maintaining the indoor environment's consistency helps ensure that the radon measurement is reliable and reflects typical conditions. However, certain testing protocols may recommend keeping windows and doors closed to prevent outside air from diluting the radon concentration. Thus, while recirculating air can be beneficial, care should be taken to follow any specific guidelines regarding windows and ventilation to achieve the most accurate results during the testing period.