Vehicle Generated Dust Transport from Unpaved Roads in Arid Climate of Juarez Mexico.

The particulate matter (PM) emission from unpaved roads starts with the pulverization of surface material by the force of the vehicle, uplifting and subsequent exposure of road to strong air currents behind the wheels. The objectives of the project were to: demonstrate the utility of a simple technique for collecting suspended airborne PM emitted by vehicle running on two unpaved road with distinctly different texture, determine the mass balance of airborne PM at different heights, and determine the particle size and elemental composition of PM. We collected dust samples on sticky tapes using a rotorod sampler mounted on a tower across two unpaved roads located within the University Agriculture Center Juarez (UACJ), Mexico and on the western periphery (Rodela Central or RCJ). Dust samples were collected at 1.5, 4.5 and 6 m height above the ground surface on the east and west side of the road. One rotorod sampler was also installed at the center of the road at 6-m height. Dust samples were mostly sand and silt sized from UACJ unpaved road (99%) and RCJ (88%). Emission factors estimated for the total suspended PM were 8985 g km^-1 at 32 km h^-1, 10147 g km^-1 48 km h^-1 and 11062 g km^-1 at 64 km h^-1 speed, respectively. The analysis of dust video showed that height and width of the PM plume also increased with speed. The PM concentration recoded by PM2.5 sensors also showed increases with increasing vehicle speeds. The analysis of dust samplers collected on sticky tapes is underway using electron microscopic and data will be presented during the conference.