Objective: Differentiate between air pollution monitoring/sampling devices and control devices.
Analysis:
\[\begin{array}{rl} \bullet & \text{(A) Bag House Filter: A control device for removing particulate matter from industrial gas streams via fabric filtration.} \\ \bullet & \text{(B) Cyclone Separator: A control device employing centrifugal force to separate particulate matter from air.} \\ \bullet & \text{(C) High Volume Sampler: A monitoring instrument for measuring ambient particulate matter concentration by drawing air through a filter. It is a sampling, not a control, device.} \\ \bullet & \text{(D) Electrostatic Precipitator (ESP): A highly efficient control device that uses electrostatic charge to remove fine particulate matter from gas streams.} \\ \end{array}\]
Conclusion:
The High Volume Sampler is identified as the device for sampling, not controlling, air pollution.