A compact portable wind tunnel for entrainable PM10 dust from soils and materials piles

A compact portable wind tunnel was designed and tested to provide a device for sampling entrainable dust particles from soils, hazardous wastes, and materials piles. The wind tunnel was developed to determine PM10 and total suspended particulates (TSP) emission factors for wind erosion from these surfaces. The wind tunnel also provides discrete or integrated samples of the greater-than and PM10 size cuts for contaminant analysis or for use as reference materials in receptor modeling. The sampling chamber is cylindrical and samples an area of about one square foot along a radial path at the outer edge and base of the chamber. Wind speeds can be selected to provide a range of approximately 5 mph to 60 mph. The entrained particles pass through a cyclone which provides the PM10-cut. The sampler measures real time entrainment using an infrared backscatter detector which has a broad linear range for concentration measurements as a function of time. Limited lab tests and field tests on a coal pile suggests that the threshold wind speed for PM10 and TSP-size particles is approximately 21 mph which differs significantly from emission modeling techniques which employ thresholds of 12 mph. The recorded duration of emissions is usually less than one minute