Further development of the high volume air sampler for high resistance filter media

The high volume air sampler is the only instrument that has been continuously successful over the last twenty years in measuring ambient concentrations of total suspended particulate (TSP). For several years, efforts have been made to rectify the artifact problems arising from the use of glass fiber filters with this sampler. The artifacts chiefly involve the reaction of sulfate and nitrate compounds with the filter paper. Other substrates have been tried, but not successfully applied, because of their higher resistance to flow. A new blower motor permits the use of all existing sampler accessories, including the flow controller. Numerous substrates have been tested to compare their capacities relevant to glass fiber paper. Tests have been run to the performance limit of the fan, with results being normalized to 24 hours.