Grantee Research Project Results
2023 Progress Report: Real-Time Analysis of Aerosol-Phase Plastic Additives in a Coastal Marine Environment in California
EPA Grant Number: R840424Title: Real-Time Analysis of Aerosol-Phase Plastic Additives in a Coastal Marine Environment in California
Investigators: Slade, Jonathan H
Institution: University of California San Diego
EPA Project Officer: Chung, Serena
Project Period: May 1, 2022 through April 30, 2025
Project Period Covered by this Report: May 1, 2023 through April 30,2024
Project Amount: $399,464
RFA: Measurement and Monitoring Methods for Air Toxics and Contaminants of Emerging Concern in the Atmosphere (2021) RFA Text | Recipients Lists
Research Category: Early Career Awards , Air Quality and Air Toxics
Objective:
The research's main goal is to quantify emerging concern contaminants, such as plastic additives, personal care product additives, and antimicrobials, within sea spray aerosol (SSA) particles along the coastal region of San Diego, CA. This will be achieved in real-time using online extractive electrospray ionization (EESI-MS) high-resolution mass spectrometry, complemented by offline measurements with ultra-high performance liquid chromatography coupled with ultra-high resolution hybrid linear ion trap-Orbitrap mass spectrometry (UHPLC-LIT-Orbitrap-MS). We aim to identify relationships between aerosol mass concentrations of these targeted contaminants and factors like season, time of day, air mass origin, wave height, and oceanic biological activity. Through non-targeted analysis, we aim to understand how these factors influence the emissions of a broad range of chemical species (both natural and anthropogenic) in sea spray aerosols.
Progress Summary:
During the current review period, significant strides were made in understanding the seasonal variations in contaminant emissions from the San Diego coastal environment. Our second field campaign, MATADOR (Measuring Airborne Toxics and Determining Oceanic Relationships), was successfully conducted in the Summer of 2023. This dataset, when compared to the Winter 2023 campaign data, will be crucial for analyzing seasonal differences. Analysis of the Winter 2023 data continues, and we published Kruse et al. (2024) in Analytical Chemistry, which explored how relative humidity and aerosol phase affect the molecular detection of components in sea spray aerosol (SSA) particles using EESI-MS.
In the work by Slade lab graduate student Adam Cooper under review, wastewater chemical pollutants in SSA in San Diego were quantified and linked, for the first time, directly to wastewater inputs from the Tijuana River during rain events. Revised data analysis shows that the concentrations of several targeted aerosol contaminants in San Diego decreased during rain events due to wet deposition but subsequently increased, linked to an increasing SSA production flux after it rains. The global estimates from this study suggested significant annual onshore fluxes of contaminants, rivaling estimates of atmospheric microplastic emissions from the sea.
A second study by Adam Cooper investigated the degradation kinetics and transformations of organic UV filter oxybenzone in seawater and SSA. This study, under review, showed that oxybenzone degrades much faster in an aerosol matrix than in seawater, with Na+ ions playing a crucial role in altering its degradation pathway, increasing toxicity post-oxidation. This work is essential for understanding the field study’s target compounds’ transformations and lifetimes.
In the work by Slade lab graduate student Samantha Kruse published in Analytical Chemistry, concentrations of key SSA components like glycerol, palmitic acid, and potassium ions during a phytoplankton bloom were tracked with EESI-MS, revealing their dependence on biological processes. The study also showed that the sensitivity of EESI-MS is significantly influenced by the aerosol phase and relative humidity, enhancing our understanding of how SSA components are detected in the atmosphere. This work marks a key advancement in data treatment for EESI-MS in complex aerosol matrices, which will be integral to future field study interpretations.
Future Activities:
Only a limited number of SSA samples from the Winter 2023 campaign have been fully analyzed. Expanding the dataset through additional quantification of trace components using optimized UHPLC-LIT-Orbitrap-MS procedures is essential to improve the reliability of our findings. Establishing a robust ion chromatography protocol to differentiate aerosol components originating from sea spray will be critical for tracing the sources of marine pollutants. Persistent challenges with signal intensity and background interference in the EESI-MS system require resolution. Efforts will address the instrument’s sensitivity to relative humidity, as identified by Kruse et al. (2024). A future field study is being planned closer to the Tijuana River emission source. Once data from the Winter and Summer 2023 campaigns are fully processed, comparing seasonal variations in contaminant emissions will be a top priority. This comparison will provide novel insights into pollutant sources and distributions.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 8 publications | 2 publications in selected types | All 2 journal articles |
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Kruse SM, Tumminello PR, Moore AN, Lee C, Prather KA, Slade JH. Effects of relative humidity and phase on the molecular detection of nascent sea spray aerosol using extractive electrospray ionization. Analytical Chemistry. 2024;96(31):12901-7. |
R840424 (2023) |
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Supplemental Keywords:
plastics, additives, aerosol, marine, mass spectrometryRelevant Websites:
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.