Trends and Elemental Concentrations in Dust in Northern Utah

The transport of dust across the Great Basin and into the Salt Lake valley is a growing concern due to its degrading effects on air quality. Utah’s population boom and the development of cities has led to greater human water consumption and more people exposed to the effects of desert dust. Consumptive use of water along the Wasatch front, prior to it running off into Great Salt Lake along with higher evaporation associated with warmer summer temperatures, has caused more dry lakebed to be uncovered providing yet another dust source, escalating the number and intensity of Dust Event Days (DEDs). In addition, the number of DEDs increase as the average daily temperatures climb and moisture in the air plummets. Drought conditions increase potential for even more exposed lake bed around Great Salt Lake and other playas. Over the past two decades dust storms have caused many exceedances of NAAQS for both PM10 (coarse particulate matter) and PM2.5 (fine particulate matter). The growth in the amount of particulate matter in the atmosphere poses a threat to human health, raising the number of hospitalizations and mortality rates due to respiratory stress. The coarse particles have been found to cause damage in the bronchial passages, but the fine particles can make it to the alveoli creating cardiovascular issues. Not only does the dust itself generate health concerns, it can also carry toxic materials and pathogens like valley fever. Recent elemental analysis of dust on snow samples using an X-Ray Flourescent (XRF) spectrometer, found trace amounts of metals and transition metals, many of which can cause adverse health effects when ingested or inhaled. Among the most concerning are Cadmium, found in 3 samples ranging from concentrations of 16.68-20.61 ppm, and Arsenic found in 3 samples ranging from 5.59-9.55 ppm. In addition, dust settling on snow decreases the albedo, accelerating melt rates and introducing the nutrients as well as the heavy metals of the dust to mountain ecosystems and streams. Human water use, climate change, agricultural practices, decreasing vegetation cover, soil disturbance, and increased construction due to urbanization are the most obvious contributing factors to the recent increase in DEDs. Monitoring and decreasing these anthropogenic influences would help reduce DEDs and in turn improve air quality in the Salt Lake Valley and along the Wasatch Front.