Three‐Decade Dust Climatology and Trend (1988–2022) From Ground Monitoring Over the Western United States

Abstract Airborne dust exerts myriad effects on climate, weather, human health and safety. In this study, 35‐year records (1988–2022) of ground aerosol observations were analyzed to identify windblown dust events from 18 Interagency Monitoring of Protected Visual Environments (IMPROVE) stations over the western United States (US). Over 45% of dust events were recorded at two sites in the Chihuahuan Desert. The intensity of dust events, indicated by regional average concentration of PM 10 (particulate matter with diameter ≤ 10 μm) during these events, decreased by −0.24 μg/m 3 per year compared to −0.10/m 3 per year on non‐dust days. However, the number and frequency of both severe dust events (24‐hr PM 10 > 40 μg/m 3 ) and moderate dust events (30 μg/m 3 < PM 10 ≤ 40 μg/m 3 ) have increased with moderate events increasing faster than severe events. The variability of dust event frequency was strongly associated with that of Pacific Decadal Oscillation (PDO) and El Niño Southern Oscillation (ENSO). The increasing wind speed has a stronger effect on the dust activity in the Northwest, whereas in the Southwest, the decreasing soil moisture has a larger impact on the increase in dust event frequency. This work provides the latest dust climatology, along with the underlying climate drivers and synoptic indicators that control the long‐term variations of dust events over the western US.