Steps to Valid Particle Size Data from Emissions Sources

Abstract

This presentation is directed toward applications of those devices most commonly applied in the measurement of industrial source particle size distributions: cascade impactors and cyclones. Quality assurance (QA) in field programs set up for the determination of particle size distributions includes many of the same steps as those for the determination of particulate concentration and emission rates such as would be applicable to Environmental Protection Agency (EPA) Methods 5 and 17. However, a number of additional levels of QA must be added. These include specifying and verifying protocols for withdrawing a representative sample from the gas stream, steps to minimize and correct for the effects of interferences, operating protocols to ensure that the sampling conditions fall within the constraints of the hardware being used, sampler preparation, sample handling, and record-keeping. Examples of specific problem areas to be addressed are (1) traverse methodology; (2) the number of samples required to obtain a given confidence level in the results; (3) the selection of samplers and the choice of operational parameters such as sampling flow rate; (4) inteferences, controls, and blanks; (5) sample recovery and handling; and (6) post-test verification that the actual sampler operation fell within the limits for reliable performance for the device(s) used.