ABSTRACT
When air pollution control agencies attempt to determine the nature and magnitude of air pollution in their communities and the effectiveness of their control programs, they collect samples of suspended and, sometimes, settleable particulate matter. Several different sampling techniques and devices—filtration, electrostatic and thermal precipitation, and impaction—may be employed to collect suspended particulate pollutants from ambient air. The Environmental Protection Agency has designated the high-volume method as the reference method for total suspended particulate matter. An excellent discussion of filter media and filtration sampling is presented in Air Sampling Instruments. Glass fiber filters have been found to meet most of the requirements for routine particulate matter sampling. Such filters have a collection efficiency of at least 99% for particles having aerodynamic diameters of 0.3 micrometers and larger, low resistance to air flow, and low affinity for moisture, all of which are distinct advantages during sampling.
