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DOI	10.5194/acp-22-15621-2022
	Different physicochemical behaviors of nitrate and ammonium duringtransport: a case study on Mt. Hua, China
	Wu, Can; Cao, Cong; Li, Jianjun; Lv, Shaojun; Li, Jin; Liu, Xiaodi; Zhang, Si; Liu, Shijie; Zhang, Fan; Meng, Jingjing; Wang, Gehui
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	15621
结束页码	15635
卷号	22 期号:23 页码:15
英文摘要	To understand the chemical evolution of aerosols in the transport process, the chemistry of PM2.5 and nitrogen isotope compositions on the mountainside of Mt. Hua (similar to 1120 m above sea level, a.s.l.) in inland China during the 2016 summertime were investigated and compared with parallel observations collected at surface sampling site (similar to 400 m a.s.l.). The PM2.5 exhibited a high level at the mountain foot site (MF; average 76.0 +/- 44.1 mu gm(-3)) and could be transported aloft by anabatic valley winds, leading to the gradual accumulation of daytime PM2.5 with a noon peak at the mountainside sampling site (MS). As the predominant ion species, sulfate exhibited nearly identical mass concentrations at both sites, but its PM2.5 mass fraction was moderately enhanced by similar to 4 % at the MS site. The ammonium variations were similar to the sulfate variations, the chemical forms of both of which mainly existed as ammonium bisulfate (NH4HSO4) and ammonium sulfate ((NH4)(2)SO4) at the MF and MS sites, respectively. Unlike sulfate and ammonium, nitrate mainly existed as ammonium nitrate (NH4NO3) in fine particles and exhibited decreasing mass concentration and proportion trends with increasing elevation. This finding was ascribed to NH4NO3 volatilization, in which gaseous HNO3 from semi-volatile NH4NO3 subsequently reacted with dust particles to form nonvolatile salts, resulting in significant nitrate shifts from fine particles into coarse particles. Such scavenging of fine-particle nitrate led to an enrichment in the daytime N-15 of nitrate at the MS site compared with to the MF site. In contrast to nitrate, at the MS site, the N-15 in ammonium depleted during the daytime. Considering the lack of any significant change in ammonia (NH3) sources during the vertical transport process, this N-15 depletion in ammonium was mainly the result of unidirectional reactions, indicating that additional NH3 would partition into particulate phases and further neutralize HSO4- to form SO42-. This process would reduce the aerosol acidity, with a higher pH (3.4 +/- 2.2) at the MS site and lower ones (2.9 +/- 2.0) at the MF site. Our work provides more insight into physicochemical behaviors of semi-volatile nitrate and ammonium, which will facilitate the improvement in the model for a better simulation of aerosol composition and properties.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000898567700001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273064
作者单位	East China Normal University; Chinese Academy of Sciences; Institute of Earth Environment, CAS; Liaocheng University; State University of New York (SUNY) System; State University of New York (SUNY) Stony Brook; Jinan University
推荐引用方式 GB/T 7714	Wu, Can,Cao, Cong,Li, Jianjun,et al. Different physicochemical behaviors of nitrate and ammonium duringtransport: a case study on Mt. Hua, China[J],2022,22(23):15.
APA	Wu, Can.,Cao, Cong.,Li, Jianjun.,Lv, Shaojun.,Li, Jin.,...&Wang, Gehui.(2022).Different physicochemical behaviors of nitrate and ammonium duringtransport: a case study on Mt. Hua, China.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(23),15.
MLA	Wu, Can,et al."Different physicochemical behaviors of nitrate and ammonium duringtransport: a case study on Mt. Hua, China".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.23(2022):15.