In-Line Filter Holder

The in-line filter holder is offered to hold 2 different sizes of filter, a 25 mm or 47 mm filter. Filters are the primary standard used for determining aerosol concentration. Filters collect particulates by interception, inertial impaction, and diffusion as the aerosol is drawn through them. The sample flow rate is a calibrated flow. Filters are weighed before and after sample collection. The weight differential is determined: post sample weight – pre-sample weight. The volume of air sampled is calculated: sample flow rate x sample time. The quotient of differential weight and sample volume is the mass per unit volume aerosol concentration. Sample weight differential can also be determined by chemical analysis rather than gravimetrically.