Impact of sand and dust storms on the atmospheric environment and its source in Tianjin-China.

Sand and dust storms (SDS) frequently hit northern China and adversely impact both environment and health. The carbonaceous components, inorganic elements, water-soluble ions, and meteorological parameters of several severe SDS episodes have been measured in a supersite in Tianjin, which is a big and representative city located in SDS transmission pathway in northern China. Six SDS episodes were identified in Spring, 2021. The maximum PM ₁₀ mass concentration was 2684 and 1664 μg/m ³ in SDS1 and SDS3, respectively. North and northwest wind was dominant and significant differences were found in wind speed and RH between the SDS and non-SDS episodes. North dust from Inner Mongolia and Mongolia was determined by back trajectory analysis as the probable source region. The mass concentration of SO ₄ ^2- , NO ₃ ^- , and NH ₄ ⁺ decreased in PM _2.5 . Increase of Na ⁺ and K ⁺ and low SO ₄ ^2- _SDS / SO ₄ ^2- _non-SDS indicate dust source for short length SDS transmission in northern China. The ratio of elements could also be used to distinguish SDS and non-SDS episodes identify north and northwest source for the SDS episodes. Pb/Al, Zn/Al, and Si/Al could be regarded as indicators for SDS and non-SDS episodes, Ca/Al and Ca/Si can help to indicate SDS source direction. This study provides a variety of evidences for the dust source identification and reveals the characteristics of the most severe SDS episodes of the decade in Tianjin during Spring 2021.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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