Abstract
The NBS portable ambient aerosol sampler is designed to collect respirable (below 3-µm) and inhalable (below 15-µm) particle size fractions for gravimetric and chemical analyses. The sampler is light, quiet and unobtrusive. We selected the components of the sampler on the basis of size, weight, price, and availability as well as performance. The inlet was intended to maintain constant collection efficiency with respect to wind speed and direction, and to include an impactor to pass particles below 15-µm aerodynamic diameter. The series filter pack was selected to collect particles above 3 µm as well as to collect a separate fine fraction (below 3 µm). The motor-pump and batteries were selected for minimum weight and maximum air pumping capacity. Reported are the sampler design criteria and results of a variety of wind tunnel and laboratory tests performed on the sampler components. We conclude that the 6 L/min, 24-h pumping capacity of the sampler is sufficient to obtain samples that can be analyzed gravimetrically, for concentrations of 10 to 100 µg/m3 of particulates.