Road dust emission and suppression, and effects of road dust on vegetation in Arches National Park, UT

Background/Question/Methods

This interdisciplinary research examines the emission of dust from unpaved roads, the potential effects fugitive dust may have on roadside vegetation, and management interventions to suppress dust loading. Field experiments were conducted to quantify dust emission on the Salt Valley Road (SVR) in Arches National Park, followed by a greenhouse study exploring dynamics of dust trapping by plants and effects this may have on ecophysiological parameters. Relationships between leaf morphology and the amount of dust collected on the leaf surface were evaluated, and photosynthetic quantum yield and transpiration were measured in four forb species over a six-week period. Chemical dust suppression using magnesium chloride was evaluated as a potential method of reducing dust loads on the SVR, and migration of Mg²⁺ and Cl^- through the soil profile alongside a treated section of road was measured.

Results/Conclusions

Results from the leaf morphology work and the magnesium chloride application on roads within the park will be discussed. Relationships were found between trichome structure, leaf surface area, and the amount of dust trapped by leaves of seven forb and grass species. Migration of Mg²⁺ and Cl^- through the soil profile was documented, with concentrations highest nearest the road the soil surface. The results of these studies were used to develop a long-term monitoring protocol for continued assessment of dust dynamics in the park, and to weigh the costs and benefits of using chemical dust suppression as a management tool.