Which type of radon measurement involves collecting air samples over an extended period?

Time-Integrated Measurement is the correct answer because this method involves collecting air samples over an extended period, typically ranging from several days to months. This approach allows for a more accurate representation of the radon levels in a given environment by averaging out fluctuations and providing a reliable estimate of exposure over time.

In contrast, grab sampling refers to taking a single, instantaneous air sample, which does not reflect average conditions. Continuous monitoring provides real-time radon levels but generally does not accumulate samples over the long term; it records data continuously but is often used for immediate assessments rather than extended evaluation. Pulsed sampling pertains to taking samples at specific intervals, which is distinct from the prolonged collection period that characterizes time-integrated measurement.