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Kasparoglu S, Meskhidze N, Petters MD. Aerosol mixing state, new particle formation, and cloud droplet number concentration in an urban environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175307. [PMID: 39142408 DOI: 10.1016/j.scitotenv.2024.175307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 07/24/2024] [Accepted: 08/04/2024] [Indexed: 08/16/2024]
Abstract
Anthropogenically derived aerosols have been hypothesized to influence convective precipitation by increasing the available pool of cloud condensation nuclei. Here, we present a synthesis of aerosol size distribution and subsaturated hygroscopicity measurements between 15 and 250 nm diameter particles during the TRacking Aerosol Convection interactions ExpeRiment (TRACER). We found that the aerosol is externally mixed and can be described by a quasi-two-component description comprising a more and less hygroscopic mode. The mean hygroscopicity parameters for these modes across all sizes were 0.03 ± 0.04 and 0.22 ± 0.08 with no significant dependence on particle size. The number fraction of the more hygroscopic mode is 40 % for particles between 15 and 40 nm and gradually increases to ~70 % for particles >100 nm. Winds from the southerly direction feature particles with larger hygroscopicity parameters and have a larger fraction of particles in the more hygroscopic mode. The hygroscopicity parameter exhibits diurnal cycles that are consistent with condensation of a species with a hygroscopicity parameter ~0.1 which corresponds to values expected for secondary organic aerosol. We also identified nine small particle events that were attributed to particle formation by nucleation. The data are consistent with new particle formation having occurred aloft, followed by downward mixing with daytime turbulence. The species that are responsible for modal growth had hygroscopicity parameters varying between 0.05 and 0.34. These values systematically depended on the wind sector, suggesting that the chemical composition of the precursors differed. Hourly cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) values derived from the aerosol size distribution, subsaturated hygroscopicity measurements, and adiabatic parcel model simulations showed a dynamic range of a factor of 2-3 in CDNC depending on the wind sector, with lower values associated with southerly onshore flow.
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Affiliation(s)
- Sabin Kasparoglu
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA; Air Quality Research Center, University of California, Davis, Davis, CA 95616, USA
| | - Nicholas Meskhidze
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Markus D Petters
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA; Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA; Center for Environmental Research and Technology (CE-CERT), University of California Riverside, Riverside, CA 92507, USA.
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Das S, McEwen A, Prospero J, Spalink D, Chellam S. Respirable Metals, Bacteria, and Fungi during a Saharan-Sahelian Dust Event in Houston, Texas. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19942-19955. [PMID: 37943153 PMCID: PMC10862556 DOI: 10.1021/acs.est.3c04158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/10/2023]
Abstract
Although airborne bacteria and fungi can impact human, animal, plant, and ecosystem health, very few studies have investigated the possible impact of their long-range transport in the context of more commonly measured aerosol species, especially those present in an urban environment. We report first-of-kind simultaneous measurements of the elemental and microbial composition of North American respirable airborne particulate matter concurrent with a Saharan-Sahelian dust episode. Comprehensive taxonomic and phylogenetic profiles of microbial communities obtained by 16S/18S/ITS rDNA sequencing identified hundreds of bacteria and fungi, including several cataloged in the World Health Organization's lists of global priority human pathogens along with numerous other animal and plant pathogens and (poly)extremophiles. While elemental analysis sensitively tracked long-range transported Saharan dust and its mixing with locally emitted aerosols, microbial diversity, phylogeny, composition, and abundance did not well correlate with the apportioned African dust mass. Bacterial/fungal diversity, phylogenetic signal, and community turnover were strongly correlated to apportioned sources (especially vehicular emissions and construction activities) and elemental composition (especially calcium). Bacterial communities were substantially more dissimilar from each other across sampling days than were fungal communities. Generalized dissimilarity modeling revealed that daily compositional turnover in both communities was linked to calcium concentrations and aerosols from local vehicles and Saharan dust. Because African dust is known to impact large areas in northern South America, the Caribbean Basin, and the southern United States, the microbiological impacts of such long-range transport should be assessed in these regions.
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Affiliation(s)
- Sourav Das
- Department
of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Alyvia McEwen
- Department
of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Joseph Prospero
- Rosenstiel
School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149, United States
| | - Daniel Spalink
- Department
of Ecology and Conservation Biology, Texas
A&M University, College
Station, Texas 77843, United States
| | - Shankararaman Chellam
- Department
of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
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Moffett CE, Mehra M, Barrett TE, Gunsch MJ, Pratt KA, Sheesley RJ. Contemporary sources dominate carbonaceous aerosol on the North Slope of Alaska. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154641. [PMID: 35307446 DOI: 10.1016/j.scitotenv.2022.154641] [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: 09/08/2021] [Revised: 03/09/2022] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
As the Arctic continues to change and warm rapidly, it is increasingly important to understand the organic carbon (OC) contribution to Arctic aerosol. Biogenic sources of primary and secondary OC in the Arctic will be impacted by climate change, including warming temperatures and earlier snow and ice melt. This study focuses on identifying potential sources and regional influences on the seasonal concentration of organic aerosol through analysis of chemical and isotopic composition. Aerosol samples were collected at two sites on the North Slope of Alaska (Utqiaġvik, UQK, and Oliktok Point, OLK, which is in an Arctic oilfield) over three summers from 2015 to 2017. The elemental carbon (EC) trends at each site were used to understand local combustion influences. Local sources drove EC concentrations at Oliktok Point, where high EC was attributed to oil and gas extraction activity, including diesel combustion emissions. Utqiaġvik had very low EC in the summer. OC was more similar in concentration and well correlated between the two sites with high contributions of contemporary carbon by radiocarbon apportionment (UQK = 74%, OLK = 63%), which could include both marine and terrestrial sources of contemporary carbon (e.g. primary and secondary biogenic, biomass burning and/or associated SOA, and bioaerosols). OC concentrations are strongly correlated to maximum ambient temperatures on the NSA during the summer, which may have implications for predicting future OC aerosol concentrations in a warming Arctic. Biomass burning was determined to be an episodic influence at both sites, based on interpretation of combined aerosol composition, air mass trajectories, and remote sensing of smoke plumes. The results from this study overall strongly suggests contribution from regional sources of contemporary organic aerosol on the NSA, but additional analysis is needed to better constrain contributions from both biogenic sources (terrestrial and/or marine) and bioaerosol to better understand temperature-related aerosol processes in the Arctic.
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Affiliation(s)
- Claire E Moffett
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Manisha Mehra
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Tate E Barrett
- Department of Environmental Science, Baylor University, Waco, TX, USA; The Institute of Ecological, Earth, and Environmental Sciences, Baylor University, Waco, TX, USA
| | - Matthew J Gunsch
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Kerri A Pratt
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Rebecca J Sheesley
- Department of Environmental Science, Baylor University, Waco, TX, USA; The Institute of Ecological, Earth, and Environmental Sciences, Baylor University, Waco, TX, USA.
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Das S, Miller BV, Prospero JM, Gaston CJ, Royer HM, Blades E, Sealy P, Chellam S. Coupling Sr-Nd-Hf Isotope Ratios and Elemental Analysis to Accurately Quantify North African Dust Contributions to PM 2.5 in a Complex Urban Atmosphere by Reducing Mineral Dust Collinearity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7729-7740. [PMID: 35670821 PMCID: PMC10069281 DOI: 10.1021/acs.est.2c01233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Tracking Saharan-Sahelian dust across the globe is essential to elucidate its effects on Earth's climate, radiation budget, hydrologic cycle, nutrient cycling, and also human health when it seasonally enters populated/industrialized regions of Africa, Europe, and North America. However, the elemental composition of mineral dust arising locally from construction activities and aeolian soil resuspension overlaps with African dust. Therefore, we derived a novel "isotope-resolved chemical mass balance" (IRCMB) method by employing radiogenic strontium, neodymium, and hafnium isotopes to accurately differentiate and quantitatively apportion collinear proximal and synoptic-scale crustal and anthropogenic mineral dust sources. IRCMB was applied to two air masses that transported African dust to Barbados and Texas to track particulate matter (PM) spikes at both locations. During Saharan-Sahelian intrusions, the radiogenic content of urban PM2.5 increased with respect to 87Sr/86Sr and 176Hf/177Hf but decreased in terms of 143Nd/144Nd, demonstrating the ability of these isotopes to sensitively track African dust intrusions even in complex metropolitan atmospheres. The principal aerosol strontium, neodymium, and hafnium end members were concrete dust and soil, soil and motor vehicles, and motor vehicles and North African dust, respectively. IRCMB separated and quantified local soil and distal crustal dust even when PM2.5 concentrations were low, opening a promising source apportionment avenue for urbanized/industrialized atmospheres.
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Affiliation(s)
- Sourav Das
- Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Brent V Miller
- Department of Geology and Geophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Joseph M Prospero
- Department of Atmospheric Sciences, University of Miami, Miami, Florida 33149, United States
| | - Cassandra J Gaston
- Department of Atmospheric Sciences, University of Miami, Miami, Florida 33149, United States
| | - Haley M Royer
- Department of Atmospheric Sciences, University of Miami, Miami, Florida 33149, United States
| | - Edmund Blades
- Department of Atmospheric Sciences, University of Miami, Miami, Florida 33149, United States
| | - Peter Sealy
- Department of Atmospheric Sciences, University of Miami, Miami, Florida 33149, United States
| | - Shankararaman Chellam
- Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, 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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