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Chang CY, Wang JL, Chen YC, Chen WN, Wang SH, Chuang MT, Lin NH, Chou CCK, Huang WS, Ke LJ, Pan XX, Ho YJ, Chen YY, Chang CC. Spatiotemporal characterization of PM 2.5, O 3, and trace gases associated with East Asian continental outflows via drone sounding. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 930:172732. [PMID: 38663609 DOI: 10.1016/j.scitotenv.2024.172732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/16/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
East Asian continental outflows with PM2.5, O3, and other species may determine the baseline conditions and affect the air quality in downwind areas via long-range transport (LRT). To gain insight into the impact and spatiotemporal characteristics of airborne pollutants in East Asian continental outflows, a versatile multicopter drone sounding platform was used to simultaneously observe PM2.5, O3, CO2, and meteorological variables (temperature, specific humidity, pressure, and wind vector) above the northern tip of Taiwan, Cape Fuiguei, which often encounters continental outflows during winter monsoon periods. By coordinating hourly high-spatial-resolution profiles provided by drone soundings, WRF/CMAQ model air quality predictions, HYSPLIT-simulated backward trajectories, and MERRA-2 reanalysis data, we analyzed two prominent phenomena of airborne pollutants in continental outflows to better understand their physical/chemical characteristics. First, we found that pollutants were well mixed within a sounding height of 500 m when continental outflows passed through and completely enveloped Cape Fuiguei. Eddies induced by significant fluctuations in wind speeds coupled with minimal temperature inversion and LRT facilitated vertical mixing, possibly resulting in high homogeneity of pollutants within the outflow layer. Second, the drone soundings indicated exceptionally high O3 concentrations (70-100 ppbv) but relatively low concentrations of PM2.5 (10-20 μg/m3), CO2 (420-425 ppmv), and VOCs in some air masses. The low levels of PM2.5, CO2, and VOCs ruled out photochemistry as the cause of the formation of high-level O3. Further coordination of spatiotemporal data with air mass trajectories and O3 cross sections provided by MERRA-2 suggested that the high O3 concentrations could be attributed to stratospheric intrusion and advection via continental outflows. High-level O3 concentrations persisted in the lower troposphere, even reaching the surface, suggesting that stratospheric intrusion O3 may be involved in the rising trend in O3 concentrations in parts of East Asia in recent years in addition to surface photochemical factors.
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Affiliation(s)
- Chih-Yuan Chang
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Jia-Lin Wang
- Department of Chemistry, National Central University, Chungli 320, Taiwan
| | - Yen-Chen Chen
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Wei-Nai Chen
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Sheng-Hsiang Wang
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Ming-Tung Chuang
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Neng-Huei Lin
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Charles C-K Chou
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Wei-Syun Huang
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Li-Jin Ke
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Xiang-Xu Pan
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Yu-Jui Ho
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Ying Chen
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan
| | - Chih-Chung Chang
- Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan.
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Im J, Mack EE, Seger ES, Löffler FE. Biotic and Abiotic Dehalogenation of 1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113): Implications for Bacterial Detoxification of Chlorinated Ethenes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11941-11948. [PMID: 31525867 DOI: 10.1021/acs.est.9b04399] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chlorofluorocarbons including 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) often occur in groundwater plumes comingled with chlorinated solvents such as trichloroethene (TCE). We show that CFC-113 inhibits reductive dechlorination by Dehalococcoides mccartyi (Dhc) in a concentration-dependent manner, causing cis-1,2-dichloroethene (cis-DCE) stalls. Following a 17-day exposure of Dhc-containing consortium SDC-9 to 76 μM CFC-113, cis-DCE dechlorination activity did not recover after CFC-113 removal. River sediment microcosms demonstrated that CFC-113 was subject to microbial degradation under anoxic conditions, and chlorotrifluoroethene (CTFE) was observed as a transformation product. No degradation of CFC-113 was observed in killed controls and in incubations with reactive minerals including mackinawite, green rust, magnetite, and manganese dioxide. In vitro experiments with reduced corrinoid (i.e., vitamin B12) mediated reductive dechlorination of CFC-113 to CTFE and trifluoroethene (TFE) followed by reductive defluorination of TFE to cis-1,2-difluoroethene (cis-DFE) as an end product. This biomimetic degradation of CFC-113 to cis-DFE was also demonstrated in vivo using the corrinoid-producing homoacetogen Sporomusa ovata, suggesting the cometabolic microbial reductive dechlorination and reductive defluorination of CFC-113 to cis-DFE is feasible under anoxic in situ conditions. The CFC-113 degradation intermediates CTFE, TFE, and cis-DFE did not inhibit TCE dechlorination by Dhc, indicating that the initial reductive transformation step can overcome cis-DCE stalls.
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Affiliation(s)
- Jeongdae Im
- Department of Civil Engineering , Kansas State University , Manhattan , Kansas 66503 , United States
| | - E Erin Mack
- Corteva Environmental Remediation , Corteva Agriscience , Wilmington , Delaware 19805 , United States
| | - Edward S Seger
- The Chemours Company , Wilmington , Delaware 19899 , United States
| | - Frank E Löffler
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
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Ou-Yang CF, Hua HC, Chou YC, Teng MK, Liu WT, Wang JL. Two-dimensional gas chromatography with electron capture detection for the analysis of atmospheric ozone depleting halocarbons. J Chromatogr A 2017; 1499:158-164. [DOI: 10.1016/j.chroma.2017.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/27/2017] [Accepted: 04/02/2017] [Indexed: 12/01/2022]
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