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Angle KJ, Grassian VH. Direct quantification of changes in pH within single levitated microdroplets and the kinetics of nitrate and chloride depletion. Chem Sci 2023; 14:6259-6268. [PMID: 37325137 PMCID: PMC10266444 DOI: 10.1039/d2sc06994f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 04/11/2023] [Indexed: 06/17/2023] Open
Abstract
The hygroscopicity and pH of aqueous microdroplets and smaller aerosols control their impacts on human health and the climate. Nitrate depletion and chloride depletion through the partitioning of HNO3 and HCl into the gas phase are processes that are enhanced in micron-sized and smaller aqueous droplets and this depletion influences both hygroscopicity and pH. Despite a number of studies, uncertainties remain about these processes. While acid evaporation and the loss of HCl or HNO3 have been observed during dehydration, there is a question as to the rate of acid evaporation and whether this can occur in fully hydrated droplets at higher relative humidity (RH). To directly elucidate the kinetics of nitrate and chloride depletion through evaporation of HNO3 and HCl, respectively at high RH, single levitated microdroplets are probed with cavity-enhanced Raman spectroscopy. Using glycine as a novel in situ pH probe, we are able to simultaneously measure changes in microdroplet composition and pH over timescales of hours. We find that the loss of chloride from the microdroplet is faster than that of nitrate, and the calculated rate constants infer that depletion is limited by the formation of HCl or HNO3 at the air-water interface and subsequent partitioning into the gas phase.
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Affiliation(s)
- Kyle J Angle
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla CA 92093 USA
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla CA 92093 USA
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Song Y, Li J, Tsona NT, Liu L, Du L. Enrichment of short-chain organic acids transferred to submicron sea spray aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158122. [PMID: 35988626 DOI: 10.1016/j.scitotenv.2022.158122] [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: 05/31/2022] [Revised: 08/10/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Organic acids, considered to be a substantial component of the marine carbon cycle, can enter the atmosphere through sea spray aerosol (SSA) and further affect the climate. Despite their importance, the distribution and mixing state of organic acids in SSA over the marine boundary layer are poorly understood and therefore need more investigation. Here, we have used ion chromatography (IC) in anion mode to measure short-chain organic acids concentrations in SSA collected throughout a custom-made SSA simulation chamber. The enrichment behavior and morphology of monocarboxylic acids (MAs, C1-8) and dicarboxylic acids (DAs) in submicron SSA were studied in seawater. We found that with MAs addition, the number concentration and mass concentration of SSA particles decreased gradually for C5-8 MAs, whereas they weakly varied with DAs addition due to the fact that carboxyl groups at both ends of DAs increased the surface tension of seawater. Moreover, the target compounds in submicron SSA displayed a surface activity-dependent enrichment behavior, where seawater with stronger surface activity, such as that containing MAs with >5 carbons, was more enriched in SSA in comparison to seawater with weaker surface activity. MAs with chain length <5 carbons were slightly enriched in SSA, whereas the enrichment factor (EF) of C5-8 MAs further increased with increasing chain length. These findings are of utmost importance in further understanding and quantifying the contribution of organic matter to SSA, which is crucial for assessing the atmosphere feedback of the marine carbon cycle. MAIN FINDING OF THE WORK: Surface tension of seawater is the key factor affecting the enrichment of short-chain organic acids in SSA.
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Affiliation(s)
- Yaru Song
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jianlong Li
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Narcisse T Tsona
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Lingrui Liu
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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Wang N, Zhang Y, Li L, Wang H, Zhao Y, Wu G, Li M, Zhou Z, Wang X, Yu JZ, Zhou Y. Ambient particle characteristics by single particle aerosol mass spectrometry at a coastal site in Hong Kong: a case study affected by the sea-land breeze. PeerJ 2022; 10:e14116. [PMID: 36325180 PMCID: PMC9620973 DOI: 10.7717/peerj.14116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 09/04/2022] [Indexed: 01/21/2023] Open
Abstract
The sea-land breeze (SLB) circulation plays a vital role in the transport of atmospheric pollutants in coastal cities. In this study, a single particle aerosol mass spectrometer (SPAMS) and combined bulk aerosol instruments were deployed to investigate the ambient particle characteristic at a suburban coastal site in Hong Kong from February 22 to March 10, 2013. Significant SLB circulations were captured from March 6-10, 2013, during the campaign. During the SLB periods, air quality worsened, with PM2.5 concentrations reaching a peak of 55.6 μg m-3 and an average value of 42.8 ± 4.5 μg m-3. A total of 235,894 particles were measured during the SLB stage. Eight major sources were identified by investigating the mixing states of the total particles, including the coal-burning related particles (48.1%), biomass burning particles (6.7%), vehicle emission-related particles (16.4%), sea salt (9.2%), ship emission particles (2.7%), dust/steeling industries (3.7%), waste incineration (6.3%), and road dust (3.9%). It was noteworthy that the PM2.5 concentrations and particle numbers increased sharply during the transition of land wind to the sea breeze. Meanwhile, the continental sourced pollutants recirculated back to land resulting in a cumulative increase in pollutants. Both individual and bulk measurements support the above results, with high contributions from coal burning, biomass burning, bulk K+, and NO3 -, which were probably from the regional transportation from the nearby area. In contrast, the ship and vehicle emissions increased during the SLB period, with a high sulfate concentration partially originating from the ship emission. In this study, field evidence of continental-source pollutants backflow to land with the evolution of sea breeze was observed and helped our current understanding of the effect of SLB on air quality in the coastal city.
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Affiliation(s)
- Nana Wang
- College of Oceanic and Atmospheric Sciences, Ocean University of Qingdao, Qingdao, China
| | - Yanjing Zhang
- College of Oceanic and Atmospheric Sciences, Ocean University of Qingdao, Qingdao, China
| | - Lei Li
- Institute of Atmospheric Environment Safety and Pollution Control, Jinan University, Guangdong, China
| | - Houwen Wang
- College of Oceanic and Atmospheric Sciences, Ocean University of Qingdao, Qingdao, China
| | - Yunhui Zhao
- College of Oceanic and Atmospheric Sciences, Ocean University of Qingdao, Qingdao, China
| | - Guanru Wu
- College of Oceanic and Atmospheric Sciences, Ocean University of Qingdao, Qingdao, China
| | - Mei Li
- Institute of Atmospheric Environment Safety and Pollution Control, Jinan University, Guangdong, China
| | - Zhen Zhou
- Institute of Atmospheric Environment Safety and Pollution Control, Jinan University, Guangdong, China
| | - Xinfeng Wang
- Environment Research Institute, Shandong University, Qingdao, China
| | - Jian Zhen Yu
- Division of Environment, Hong Kong University of Science and Technology, Kowloon, Hong Kong,Department of Chemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Yang Zhou
- College of Oceanic and Atmospheric Sciences, Ocean University of Qingdao, Qingdao, China
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Chen Z, Liu P, Su H, Zhang YH. Displacement of Strong Acids or Bases by Weak Acids or Bases in Aerosols: Thermodynamics and Kinetics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12937-12944. [PMID: 36049086 DOI: 10.1021/acs.est.2c03719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Depletion of chloride, nitrate, or ammonium from atmospheric aerosols represents a unique class of displacement reactions in which strong acids (HCl and HNO3) or bases (NH3) are substituted by weaker ones (i.e., dicarboxylic acids or dicarboxylate salts, respectively). These reactions alter the aerosol composition and perturb the atmospheric cycle of volatile compounds, thereby affecting environmental systems and climate. Despite the profound implications, the mechanism of these unique displacement reactions remains unclear. Here, we elucidate the thermodynamics and kinetics of these reactions using the multiphase buffer theory and a diffusion-controlled mass-transfer function, respectively. On the thermodynamic aspect, we find that the effective dissociation constants of the strong acids and bases in aerosols are 2 to 10 orders of magnitude lower than those in bulk solutions. On the kinetic aspect, we find that displacement reactions occur rapidly in aerosol microdroplets with a radius below 10 μm. Within this size range, the characteristic reaction time is always shorter than the lifetime of the aerosols in the atmosphere. Our findings suggest that the unique displacement reactions can significantly modify the composition of atmospheric aerosols, and consequentially, these aerosols may manifest distinct properties unforeseen by the chemistry of homogeneous bulk systems.
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Affiliation(s)
- Zhe Chen
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Pai Liu
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Hang Su
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Yun-Hong Zhang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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Wang S, Yan J, Lin Q, Zhao S, Xu S, Li L, Zhang M, Chen L. Non-ignorable contribution of anthropogenic source to aerosols in Arctic Ocean. ENVIRONMENTAL RESEARCH 2021; 201:111538. [PMID: 34166656 DOI: 10.1016/j.envres.2021.111538] [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: 03/16/2021] [Revised: 05/23/2021] [Accepted: 06/12/2021] [Indexed: 06/13/2023]
Abstract
Arctic Ocean (AO) atmospheric aerosols, which are a factor influencing regional and global climate, have been greatly influenced by an increase in anthropogenic sources. To identify the impact of anthropogenic sources on regional aerosols in the AO and middle and low latitudes (MLO), a single-particle aerosol mass spectrometer was used to count and size aerosols with diameters less than 2.5 μm (PM2.5) and determine their chemical composition. The mean hourly count of PM2.5 aerosols was 1639/h in the AO, which was 57.1% lower than that in the MLO. Na_MSA, sulfate, and Na_rich were three major components, which accounted for 74.3% of PM2.5 aerosols in the AO. The size distribution of PM2.5 aerosols was unimodal, peaking between 0.42 μm and 1.64 μm. A source apportionment method for single aerosol particles in the Arctic was established using positive matrix factorization (PMF) combined with backward air mass trajectory and principal component analysis (PCA). Three potential sources of aerosols were identified: marine sources; anthropogenic sources; and secondary formation. The largest contribution to aerosols in the AO was from marine sources, accounting for 50.6%. This source was 20.4% higher in the AO than that in the MLO. Secondary formation contributed 19.8% and 36.5% to aerosols in the AO and MLO, respectively. However, the contribution of anthropogenic sources to aerosols was 29.6% in the AO, and this was 3.7% lower than that in the MLO. Our study provides a useful method for identifying sources of aerosols in the Arctic, and the results showed that although marine sources were the largest contributors to aerosols in the AO, the contribution of anthropogenic sources could not be ignored.
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Affiliation(s)
- Shanshan Wang
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Jinpei Yan
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.
| | - Qi Lin
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Shuhui Zhao
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Suqing Xu
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Lei Li
- Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou, 510632, China
| | - Miming Zhang
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Liqi Chen
- Key Laboratory of Global Change and Marine Atmospheric Chemistry, Ministry of Natural Resources, Xiamen, 361005, China; Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
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