气候变化领域集成服务门户(CCPortal): Long-term declines in atmospheric nitrogen and sulfur deposition reduce critical loads exceedances at multiple Canadian rural sites, 2000-2018

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DOI	10.5194/acp-22-14631-2022
	Long-term declines in atmospheric nitrogen and sulfur deposition reduce critical loads exceedances at multiple Canadian rural sites, 2000-2018
	Cheng, Irene; Zhang, Leiming; He, Zhuanshi; Cathcart, Hazel; Houle, Daniel; Cole, Amanda; Feng, Jian; O'Brien, Jason; Macdonald, Anne Marie; Aherne, Julian; Brook, Jeffrey
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	14631
结束页码	14656
卷号	22 期号:22 页码:26
英文摘要	Daily air concentrations of inorganic nitrogen (N) species, including gaseous HNO3 and particulate-bound (p)NH4+ and pNO(3)(-), and sulfur (S) species, including SO2 and pSO(4)(2-), and precipitation concentrations of NO3-, NH4+, and SO42-, have been routinely monitored by the Canadian Air and Precipitation Monitoring Network (CAPMoN) since 1983. Data at 15 rural sites from 2000-2018 were used to estimate dry and wet N and S deposition fluxes, which were then used to explore their spatiotemporal trends and assess ecosystem damage through a retrospective analysis of critical loads (CLs) exceedances. Total (dry + wet) N deposition ranged from 1.7-9.5 kg N ha(-1)yr(-1) among the 15 sites, though dry deposition of NH3 and some oxidized N species were not included due to lack of monitoring data. Based on additional N measurements in 2010 at one of the sites, annual total N deposition may be underestimated by up to 32 %. Total N deposition was dominated by wet NO3- and wet NH4+ deposition, which together comprised 71 %-95 %. Contributions to dry N deposition were 40 %-74 % by HNO3, 11 %-40 % by pNH(4)(+), and 5 %-25 % by pNO(3)(-). Total S deposition ranged from 1.3-8.5 kgSha(-1)yr(-1) and was dominated by wet deposition of SO42- and dry deposition of SO2. Relative percentages of wet and dry S deposition were 45 %-89 % and 11 %-55 %, respectively. Acidic ion fluxes were greatest in southeastern Canada and were comparable among the west coast, prairie, remote, and eastern Canadian sites. Oxidized N (dry HNO3, dry pNO(3)(-), wet NO3-) deposition was greater than that of reduced N (dry pNH(4)(+), wet NH4+) in the early 2000s. In 2014-2018, reduced N deposition surpassed that of oxidized N in southeastern Canada. Total N and S deposition decreased significantly at a rate of -0.03 to -0.25 kgNha(-1)yr(-1) (-1.1 % yr(-1) to -3.3 %yr(-1)) and -0.08 to -0.66 kgSha(-1)yr(-1) (-3.5 % yr(-1) to -6.6 %yr(-1)), respectively, among the sites. The weak declining trend in total N deposition at the west coast site was consistent with the slower decline in NOx emissions in western Canada. Reductions in total N deposition were driven by its oxidized form as trends in reduced N were non-significant. As a result, reduced N contributions to total N deposition increased on average from 42 % in 2000-2004 to 53 % in 2014-2018. Anthropogenic NOx and SO2 emissions reductions in both eastern Canada and eastern US were highly effective in reducing total oxidized N and total S deposition, respectively, in eastern Canada. Acidic deposition exceeded terrestrial CL at 5 of the 14 sites and aquatic CL at 2 of the 5 sites in the early 2000s. However, exceedances have been trending downwards and acidic deposition fluxes were mostly near or below CL after 2012 for the subset of sites assessed, which support recovery from historical acidification. Further assessments of CL exceedances are required in other Canadian regions susceptible to acidification and affected by elevated or increasing N and S emissions.
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:000886694500001
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/273221
作者单位	Environment & Climate Change Canada; Environment & Climate Change Canada; Trent University; University of Toronto
推荐引用方式 GB/T 7714	Cheng, Irene,Zhang, Leiming,He, Zhuanshi,et al. Long-term declines in atmospheric nitrogen and sulfur deposition reduce critical loads exceedances at multiple Canadian rural sites, 2000-2018[J],2022,22(22):26.
APA	Cheng, Irene.,Zhang, Leiming.,He, Zhuanshi.,Cathcart, Hazel.,Houle, Daniel.,...&Brook, Jeffrey.(2022).Long-term declines in atmospheric nitrogen and sulfur deposition reduce critical loads exceedances at multiple Canadian rural sites, 2000-2018.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(22),26.
MLA	Cheng, Irene,et al."Long-term declines in atmospheric nitrogen and sulfur deposition reduce critical loads exceedances at multiple Canadian rural sites, 2000-2018".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.22(2022):26.