Chemical compositions of fog and precipitation at Sejila Mountain in the southeast Tibetan Plateau, China

Wang, Wei; Xu, Wen; Collett, Jeffrey L.; Liu, Duanyang; Zheng, Aihua; Dore, Anthony J.; Liu, Xuejun

doi:10.1016/j.envpol.2019.07.055

Cited by 33 publications

(20 citation statements)

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“…+ concentrations [37]. Average atmospheric NH 3 and NO 2 concentrations across China are 6.1 and 6.8 µg N m −3 [28], almost 2.6 and 7.4 times than those in our research area, respectively.…”

Section: Variation Of Monthly Bulk Nr Concentrations and Atmospheric ...mentioning

confidence: 44%

Atmospheric Nitrogen Deposition to a Southeast Tibetan Forest Ecosystem

et al. 2020

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With atmospheric reactive nitrogen (Nr) emissions increasing globally, research into Nr deposition has attracted increasing attention, especially in remote environments. These ecosystems are very sensitive to global change, especially enhanced Nr deposition. Forest environments, in particular, are highlighted because of their important ecological function. We quantified atmospheric Nr concentrations and deposition over four years of continuous monitoring in a southeast Tibetan boreal forest ecosystem, an ecosystem in which forest biomass and carbon density are high around the world. Average annual bulk Nr deposition was 3.00 kg N ha−1 y−1, with those of reduced and oxidized species estimated at 1.60 and 1.40 kg N ha−1 y−1, respectively. Bulk deposition of both NH4+ and NO3− were controlled by precipitation amount: both Nr deposition and precipitation were highest in summer and lowest in winter. Dry deposition of NH3 and NO2 were 1.18 and 0.05 kg N ha−1 y−1, respectively. Atmospheric NH3 concentrations were in the range 1.15–3.53 mg N L−1, highest in summer and lowest in winter. In contrast, no clear trend in seasonal NO2 concentrations was observed. Monthly NO2 concentrations were 0.79–1.13 mg N L−1. Total Nr deposition (bulk plus dry) was 4.23 (3.00 + 1.23) kg N ha−1 y−1 in the forest. Reduced nitrogen was the dominant species. In conclusion, Nr deposition was in the range at which forest net productivity and carbon sequestration are sensitive to any variation in nitrogen input, so quantification of Nr deposition should continue and with greater detail.

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Section: Variation Of Monthly Bulk Nr Concentrations and Atmospheric ...mentioning

confidence: 44%

Atmospheric Nitrogen Deposition to a Southeast Tibetan Forest Ecosystem

et al. 2020

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“…However, our observed high D 17 O(SO 2-4 )SAS values suggest the importance of sulfate formation by aqueous oxidation of S(IV) by O3, indicating that sulfate formation is occurring at relatively high pH conditions. Indeed, the pH in fog, rain and snow in the TP region were reported to be high, respectively, pH = 6.4, 6.2, and 5.96 ± 0.54 (Wang et al, 2019a;Kang et al, 2002), and the modeled cloud water pH in the Mt. Everest region and the South Asia showed approximately pH = 6 (Shah et al, 2020;Pye et al, 2020).…”

Section: Importance Of Atmospheric Acidity For Sulfate Formation Pathwaysmentioning

confidence: 99%

Comment on acp-2020-1279

2021

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As an important atmosphere constituent, sulfate aerosols exert profound impacts on climate, ecological environment, and human health. The Tibetan Plateau (TP), identified as the 'Third Pole', contains the largest land ice masses outside the poles and has attracted wide attention on its environment and climatic change. However, the mechanisms of sulfate formation in this specific region remain poorly characterized. Oxygen-17 anomaly (D 17 O) has been used as a probe to constrain the relative importance of different pathways leading to sulfate formation. Here, we report the D 17 O values in atmospheric sulfate collected at a remote site in the Mt. Everest region to decipher the possible formation mechanisms of sulfate in such a pristine environment. Throughout the sampling campaign (April-September 2018), the D 17 O in non-dust sulfate show an average of 1.7 ± 0.5‰ which is higher than most existing data in modern atmospheric sulfate. The seasonality of D 17 O in non-dust sulfate exhibits high values in the pre-monsoon and low values in the monsoon, opposite to the seasonality in D 17 O for both sulfate and nitrate (i.e., minima in warm season and maxima in cold season) observed from diverse geographic sites. This high D 17 O in non-dust sulfate found in this region clearly indicates the important role of the S(IV) + O3 pathway in atmospheric sulfate formation promoted by high cloud water pH condition. Overall, our study provides an observational constraint on atmospheric acidity in altering sulfate formation pathways particularly in dust-rich environments, and such identification of key processes provides an important basis for a better understanding of the sulfur cycle in the TP.

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“…Cations (Na + , NH4 + , K + , Mg 2+ , and Ca 2+ ) were analyzed on a DX-600 ion chromatograph that consisted of a separation column (Dionex CS12A) and a guard column (Dionex AG12A), and the detection limit was 0.1 μg/L. The amount of HCO3 − was estimated using the following equation: HCO3 − = 10 (pH−5.05) [20].…”

Section: Chemical Analysismentioning

confidence: 99%

Chemical Compositions of Rainfall Water in Nyingchi City, Tibet

et al. 2022

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Understanding precipitation chemistry is highlighted as important worldwide due to its close relationship with air quality and impacts on ecosystems. However, the chemical composition of precipitation is limited in Tibet, where alpine ecosystems are sensitive to global change. Here, rainwater samples were collected in Nyingchi city from January 2021 to December 2021, and a total of 44 samples were obtained. Major ions (NO3−, NH4+, Cl−, SO42−, Na+, K+, Ca2+ and Mg2+) were analyzed. Results showed that the predominant ions in the precipitation were Ca2+, Na+, SO42−, and Cl−. Precipitation was mainly concentrated in summer, accounting for 65.2% of all samples collected during the monitoring period. As a result, ion deposition fluxes were mainly concentrated in summer, accounting for 55%, 53%, 84%, 82%, 61%, 63%, 75.8%, and 37.8% of the annual Ca2+, K+, Mg2+, Na+, NH4+, Cl−, SO42−, and NO3−, respectively. Backward trajectory analysis revealed that airmasses were mainly from the southern direction, but the sources varied widely. In addition, Na+ and Cl− ions were dominated by the sea source fraction; the ions of Ca2+ and K+ were dominated by crustal fraction sources. The NH4+ and NO3− ions were mainly influenced by local pollution. However, SO42− was mainly from long distance transports. Our results suggest that ions abundance was varied largely in different direction airmasses in southeast Tibet. Considering that ion deposition fluxes were mainly concentrated in the summer and the airmasses were mainly from the southern direction in this season, the pollutants from the southern direction the environmental effects of those ions should be given more attention in the future.

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Chemical compositions of fog and precipitation at Sejila Mountain in the southeast Tibetan Plateau, China

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Cited by 33 publications

References 92 publications

Atmospheric Nitrogen Deposition to a Southeast Tibetan Forest Ecosystem

Atmospheric Nitrogen Deposition to a Southeast Tibetan Forest Ecosystem

Comment on acp-2020-1279

Chemical Compositions of Rainfall Water in Nyingchi City, Tibet

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