Laboratory Testing Method for PM-10 Samplers: Lowered Effectiveness from Particle Loading

Abstract

Field tests have revealed large differences in the sampling efficiencies among PM-10 samplers which previously satisfied U.S. Environmental Protection Agency (EPA) performance requirements in wind tunnel testing. To investigate the causes resulting from processes internal to the samplers, a laboratory testing method was developed based on the introduction of aerosol to the sampler in a manner than approximates ambient sampling. The method was verified by showing that filter deposit uniformity and measurements of sampling effectiveness agree with field and wind tunnel data. The 50% cutpoints of a Wedding PM-10 sampler and an oiled Sierra Anderson 321A sampler loaded with deposits from the EPA Phoenix III field study were found to be lower than those for the clean samplers. Analysis of these data and data from Phoenix III shows that the sampling effectiveness of a PM-10 sampler with an oiled collection surface decreases with loading.