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Upcoming Seminar

Sources and Characteristics of Particulate Matter in an Urban/Agricultural/Desert Setting

Wed, Jan 27, 2021

270 Seminar

Speaker: Roya Bahreini

Institution: UC Riverside

Abstract:

The Imperial Valley is the second largest agricultural region in California and is home to the Salton Sea, the largest endorheic lake west of the Mississippi. The Imperial County communities surrounding the Salton Sea suffer from extreme levels of air pollution, especially aerosol particles. This has led to negative health outcomes and low socioeconomic factors. Due to the high input of agricultural runoffs in the lake over the past decades, its salinity has been increasing to twice as much as ocean water. Additionally, concentrations of selenium (Se) in the water and sediments are high and increasing. Recent water management practices in the region have led to a sharp decrease in the Salton Sea water levels, worsening its water quality, and exposing the playa along its shores. Primary dust emissions from the recently exposed playa mobilize trace pollutants to the atmosphere and contribute to the region’s PM2.5 and PM10 (aerosols ≤ 2.5 mm and 10 mm in aerodynamic size, respectively) concentrations.

In this talk, I present results on mineral and ionic composition of suspended and depositing aerosols in Imperial Valley to determine sources of airborne dust particles and quantify the influence of the exposed playa vs. the local arid lands in controlling dust emissions. I will also examine the spatial and temporal patterns of aerosol components using data from passive samplers deployed at five sites, spanning from the remote/background to urban and shoreline locations in IV. Enrichment factors and positive matrix factorization (PMF) results were used to identify and to estimate the contribution of various dust sources in the region. The PMF resolved the data from these samplers with seven factors, six of which have anthropogenic influences, contributing to 55-80% of the collected aerosol mass. Additionally, we determined that playa emissions were most intense during late spring/early summer. Minerology of the collected samples during an intense dust event suggest that evaporite minerals of playa, particularly magnesium and sulfate, are important for playa emissivity. In our first study at the Salton Sea, we observed strong seasonal variations in Se concentrations with higher enrichments on fine aerosols, suggesting a seasonal cycle of Se volatilization from the playa and/or the sediments and formation of secondary aerosols through condensation. I will conclude the seminar with results from our laboratory-based experiments examining the potential for atmospheric oxidation of organoselenium compounds to contribute to Se-enrichment in ambient aerosols.

Zoom: https://ucla.zoom.us/j/98770296517

Blanca Alvarez	Graduate Student	balvarez [at] atmos.ucla.edu
Tersi Arias	Graduate Student	tersiarias [at] atmos.ucla.edu
Alex Arnold	Graduate Student
Catherine Banach		cbanach [at] atmos.ucla.edu
Marco Sandoval Belmar	Graduate Student	marcsandovalb [at] atmos.ucla.edu
Nathaniel Brockway	Graduate Student	nwbrock [at] atmos.ucla.edu
Zhijiong Cao	Graduate Student	czj9763 [at] g.ucla.edu
Santiago Giraldo Cardenas	Graduate Student	santigiraldoc [at] atmos.ucla.edu
Daniel Clements	Graduate Student	dclements [at] atmos.ucla.edu
Jackson Darke	Graduate Student	jdarke40 [at] atmos.ucla.edu
Xiuyuan Ding	Graduate Student	dingxy [at] atmos.ucla.edu
Todd Emmenegger	Graduate Student	temmen [at] atmos.ucla.edu
Alyson Fritzmann		afritzmann [at] ucla.edu
Bowen Ge		gebowen [at] ucla.edu
Sara Graves		saragraves [at] ucla.edu
Paige Hoel	Graduate Student	paigehoel [at] atmos.ucla.edu
Calvin Howes	Graduate Student	calvinhowes [at] atmos.ucla.edu
Yue Huang	Graduate Student	yhuang [at] atmos.ucla.edu
Sarah Johnson	Graduate Student	sjohnson [at] atmos.ucla.edu
Ning Kang		nkang20 [at] atmos.ucla.edu
Yi-Hung Kuo	Graduate Student	yhkuo [at] atmos.ucla.edu
Danny Leung	Graduate Student	dannymleung [at] g.ucla.edu
Jiawen Li	Graduate Student	jiawen0110 [at] atmos.ucla.edu
Bessie Liu	Graduate Student	bessieliu [at] ucla.edu
Weiming Ma	Graduate Student	mawei [at] atmos.ucla.edu
Donglai Ma	Graduate Student	dma96 [at] atmos.ucla.edu
Gavin Madakumbura	Graduate Student	gavindayanga [at] atmos.ucla.edu
Daniel McCoy	Graduate Student	demccoy [at] atmos.ucla.edu
Matthew McKinney	Graduate Student	mmckinney [at] atmos.ucla.edu
Jordyn Moscoso	Graduate Student	jmoscoso [at] atmos.ucla.edu
Zoe Pierrat	Graduate Student	zpierra [at] atmos.ucla.edu
Mingxin Qu	Graduate Student	mingxin23 [at] atmos.ucla.edu
De'Marcus Robinson	Graduate Student	demarcu1.robinson [at] atmos.ucla.edu
Rodrigo Rodakoviski	Graduate Student	rodakoviski [at] atmos.ucla.edu
Jiaqi Shen	Graduate Student	jqshen [at] ucla.edu
Zhan Shi		zhanshi1997 [at] gmail.com
Clara Si	Graduate Student	csi [at] atmos.cula.edu
Dominique Stumbaugh		NSTUMBAUGH07 [at] GMAIL.COM
Katie Tuite	Graduate Student	ktuite [at] atmos.ucla.edu
Francis Turney	Graduate Student	fturney [at] ucla.edu
Sarah Worden	Graduate Student
Kyongwon (Kevin) Yoo	Graduate Student	kyongwonyoo93 [at] atmos.ucla.edu
Ken Zhao	Graduate Student	kzhao [at] atmos.ucla.edu
Zewen Zheng	Graduate Student	zewenzheng [at] atmos.ucla.edu
Kuilin Zhu		kuilin [at] g.ucla.edu

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