A Comprehensive Study of Particulate Matter (PM) in the Eastern Coachella Valley (ECV) Community: Mass Closure and Comparisons between Time Integrated Sampling and Real-Time Continuous Monitoring Data
JOSEPH SALAZAR, Yumeng Cui, Julia Montoya-Aguilera, Christopher Lim, Mohammad Sowlat, Steven Boddeker, Freyja Berg Lopez, Laura Saucedo, Cynthia Berg, Angela Haar, Stephen Dutz, James Rothchild, Eric Holden, Sina Hasheminassab, Matic Ivančič, Martin Rigler, Payam Pakbin, Andrea Polidori, Jason Low, South Coast Air Quality Management District
Abstract Number: 447
Working Group: Source Apportionment
Abstract
The enactment of Assembly Bill (AB) 617 by the California legislature and establishment of the Community Air Protection Program (CAPP) by California Air Resources Board (CARB) provided the opportunity for the South Coast Air Quality Management District (South Coast AQMD) to address air quality issues in communities that are disproportionately impacted by air pollution. Eastern Coachella Valley (ECV) is an AB 617-designated community in the Salton Sea Air Basin that is impacted by several sources of particulate matter (PM), including desert and Salton Sea playa dust, agricultural burning, and motor vehicles. South Coast AQMD developed and implemented a comprehensive study from January 2022 through May 2023 to better characterize PM/dust and identify its sources and origins in the area. This campaign relied on a combination of time-integrated PM sampling techniques and time-resolved measurements by continuous monitors to fully characterize physical characteristics (size, shape, and morphology) and chemical composition (i.e., carbonaceous compounds, trace metals, and ions) of the PM/dust in this area.
This is part of two accompanying abstracts submitted to report on the results from this campaign. In this presentation, we will evaluate mass closure and chemical agreement between time-integrated and real-time PM10 measurements collected side-by-side at a school located in a residential neighborhood within ECV. Reconstructed mass (Σ ions + elements + OMC + EC) was compared to PM₁₀ Mass for closure analysis. Mass-closure calculations were performed independently for each platform; seasonal composites were then compared to identify systematic biases and source-specific discrepancies. Results show that estimated reconstructed mass varied appreciably with season. Continuous monitors and time-integrated method generally under-predicted gravimetric mass. Despite these offsets, both approaches captured coherent temporal trends and similar elemental profiles, indicating that five major PM₁₀ contributors—natural dust, chlorine-rich sources, Salton Sea emissions, agricultural/industrial activity, and secondary aerosol that drive PM10 dynamics in ECV.