Understanding the spatial and temporal variability in fine mineral dust (FD, mineral aerosols with diameters less than 2.5 µm) and coarse aerosol mass (CM, mass of aerosols with diameters between 2.5 and 10 µm) is important for accurately characterizing and perhaps mitigating their environmental and climate impacts, which include influences on air quality, visibility, radiative forcing, hydrology, heterogeneous chemistry, biogeochemistry, and ecology. The spatial and seasonal variability of ambient FD and CM was characterized at rural and remote sites across the United States using data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) aerosol monitoring network. In addition, urban CM across the United States was determined using the Environmental Protection Agency's PM2.5 and PM10 Federal Reference Method (FRM) networks. Urban and rural CM data were integrated to create a continental-scale dataset of daily, monthly, seasonal, and annual mean CM concentrations. Comparisons of CM and FD indicate similar sources (e.g., mineral aerosols) in some regions and additional CM sources in other regions. Long-term trend analyses suggest that unlike secondary aerosols, both FD and CM have increased over certain regions and seasons, and their contributions to PM2.5 and PM10 mass, respectively, also have increased. As PM2.5 mass continues to decrease across the United States, it is increasingly important to understand the seasonal and temporal variability, composition, and sources of FD and CM and their contributions to the mass budget.
Jenny Hand is a Senior Research Scientist at the Cooperative Institute for Research in the Atmosphere (CIRA) at Colorado State University. Her research interests include a broad set of aerosol-related questions, including transport and deposition of mineral dust; properties of organic aerosol from biomass burning; and regional haze. Jenny earned her B.S. degrees in Physics and Astronomy from the University of Kansas, and a Ph.D. in Atmospheric Science from Colorado State University. She serves as the PI for the National Park Service / CIRA cooperative agreement to investigate issues related to visibility degradation in national parks.
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