Since the 1980’s, SWA has operated field evaluations of coal dust suppressants on rail cars. Typical field evaluations should consist of half treated trains with deployment of Passive Collectors (PCs) and Rail Transport Emission Profiling System (RTEPS) units.Passive Collectors sample the dust emitted from an in-transit coal car during its entire trip. By deploying PCs on both treated and untreated cars, a measure of the dust reduction benefit of the treatment can be determined. RTEPS is a realtime portable weather station used to determine the level of environmental stresses acting on a test train, including:

• Anemometer (Wind Speed)
• Infrared Temperature Sensor (Coal Surface Temperature)
• Rain Gage (precipitation)
• Thermocouple (Ambient Temperature)
• Realtime Aerosol Monitor
• GPS

Trains are half treated and half untreated (i.e., first half of the trains' cars are treated, while the second half of the trains cars are untreated for a control sample) will have multiple Passive Collector and RTEPS-equipped cars to allow for direct comparison of relative dust emissions from the treated and untreated cars.  This technique of testing on individual trains under the same environmental and external stresses (i.e., handling, cross-overs, etc.) allows for the determination of an in-transit dust suppressant's effectiveness by minimizing the uncontrolable variables.

TrackSide Monitors (TSMs) are useful for longterm continuous monitoring of dust emissions from passing coal trains. TSMs consists of realtime weather and dust monitoring equipment that operate continuous 24x7x365.  Dust and weather conditions are matched with train data to identify longterm trends of dustiness (i.e., by mine, by treatment, etc.).  Monitored conditions include:

• Ambient Dust (Total Suspended Particulates - TSP, PM₁₀, PM_2.5, or PM₁)
• Wind Speed and Direction
• Temperature
• Relative Humidity
• Precipitation
• Train Speed