An air sampling device samples air in a controlled environment. The device includes a housing body having a top and a side. An opening is located at the top of the housing body. A retaining assembly retains a sampling device and atrium. The retaining assembly is located at the top of the housing body about the opening. A plenum has a top end and a bottom end, with the top end coupled to the top of the housing body about the opening so that the plenum is in flow communication with the opening. A mass flow meter has an input and an output, with the input coupled to the bottom end of the plenum and in flow communication with the bottom end of the plenum. A blower is located inside the plenum and is configured to draw air past the sampling device, through the opening, through the plenum, and through the mass flow meter. The mass flow meter detects a flow rate of air through the mass flow meter. And a controller receives the detected flow rate from the mass flow meter and controls a speed of the blower in response to the detected flow rate. The controller increases the speed of the blower if the detected flow rate is lower than a desired flow rate, and decreases the speed of the blower if the detected flow rate is higher than a desired flow rate.