On the modification of the low flow-rate PM10 dichotomous sampler inlet

A popular flat-topped inlet used for the collection of atmospheric particul ate matter was modified to reduce water intrusion during rain and snow even ts. Simple alterations in the intake region of this inlet were made, includ ing a larger drain hole, a one piece top plate, and louvers.Wind tunnel tes ts were performed at 24 km/h for fine particle aspiration and at 2, 8, and 24 km/h for coarse particle sampling characteristics of the modified design . The laboratory evaluations of this inlet for line (PM2.5) and coarse (PM1 0) particle sampling demonstrated that the aspiration characteristics of th is inlet were identical to those of the original inlet. This inlet should g reatly reduce, if not totally prevent, the intrusion of precipitation. Furt her, sampling effectiveness test results suggest that the modified inlet co uld be substituted for the original inlet where the original inlet is part of a designated reference or equivalent method sampler for PM10.