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Zhou S, Guo F, Chao CY, Yoon S, Alvarez SL, Shrestha S, Flynn JH, Usenko S, Sheesley RJ, Griffin RJ. Marine Submicron Aerosols from the Gulf of Mexico: Polluted and Acidic with Rapid Production of Sulfate and Organosulfates. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5149-5159. [PMID: 36939598 DOI: 10.1021/acs.est.2c05469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We measured submicron aerosols (PM1) at a beachfront site in Texas in Spring 2021 to characterize the "background" aerosol chemical composition advecting into Texas and the factors controlling this composition. Observations show that marine "background" aerosols from the Gulf of Mexico were highly processed and acidic; sulfate was the most abundant component (on average 57% of total PM1 mass), followed by organic material (26%). These chemical characteristics are similar to those observed at other marine locations globally. However, Gulf "background" aerosols were much more polluted; the average non-refractory (NR-) PM1 mass concentration was 3-70 times higher than that observed in other clean marine atmospheres. Anthropogenic shipping emissions over the Gulf of Mexico explain 78.3% of the total measured "background" sulfate in the Gulf air. We frequently observed haze pollution in the air mass from the Gulf, with significantly elevated concentrations of sulfate, organosulfates, and secondary organic aerosol associated with sulfuric acid. Analysis suggests that aqueous oxidation of shipping emissions over the Gulf of Mexico by peroxides in the particles might potentially be an important pathway for the rapid production of acidic sulfate and organosulfates during the haze episodes under acidic conditions.
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Affiliation(s)
- Shan Zhou
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Fangzhou Guo
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Chun-Ying Chao
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Subin Yoon
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, United States
| | - Sergio L Alvarez
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, United States
| | - Sujan Shrestha
- Department of Environmental Science, Baylor University, Waco, Texas 76798, United States
| | - James H Flynn
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, United States
| | - Sascha Usenko
- Department of Environmental Science, Baylor University, Waco, Texas 76798, United States
| | - Rebecca J Sheesley
- Department of Environmental Science, Baylor University, Waco, Texas 76798, United States
| | - Robert J Griffin
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
- School of Engineering, Computing and Construction Management, Roger Williams University, Bristol, Rhode Island 02809, United States
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Guberman VerPloeg SL, Clark AE, Yoon S, Hildebrandt Ruiz L, Sheesley RJ, Usenko S. Assessing the atmospheric fate of pesticides used to control mosquito populations in Houston, TX. CHEMOSPHERE 2021; 275:129951. [PMID: 33662722 DOI: 10.1016/j.chemosphere.2021.129951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
During the summer months, urban areas are literal hot spots of mosquito-borne disease transmission and air pollution. Public health authorities release aerosolized pesticides directly into the atmosphere to help control adult mosquito populations and thereby reduce the threat of diseases, such as Zika Virus. The primary adulticides (i.e. pesticides used to control adult mosquito populations) in Houston, TX are permethrin and malathion. These adulticides are typically sprayed at night using ultra-low volume sprayers. Particulate matter (PM) samples including total suspended and fine PM (PM < 2.5 μm in aerodynamic diameter) were collected at four ground-based sites across Houston in 2013 and include daytime, nighttime, and 24 h samples. Malathion is initially sprayed as coarse aerosol (5-25 μm), but is measured in fine aerosol (<2.5 μm) and coarse aerosol in the urban atmosphere. Particle size is relevant both for deposition velocities and for human exposure. Atmospheric permethrin concentrations measured in nighttime samples peak at 60 ng m-3, while malathion nighttime concentrations peak near 40 ng m-3. Malaoxon, an oxidation product of malathion, was also frequently detected at concentrations >10 ng m-3, indicating significant nighttime oxidation. Based on the loss of malathion and the increase in malaoxon, the atmospheric half-life of malathion in Houston was estimated at <12 h, which was significantly shorter than previous half-life estimates (∼days). Importantly, malaoxon is estimated to be 22-33 times more toxic to humans than malathion. Both the aerosol size and the half-life are critical for mosquito control, human exposure, and risk assessment of these routine pesticides.
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Affiliation(s)
| | - Adelaide E Clark
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
| | - Subin Yoon
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX, 76798, USA
| | - Lea Hildebrandt Ruiz
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA
| | - Rebecca J Sheesley
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX, 76798, USA
| | - Sascha Usenko
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX, 76798, USA; Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA.
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