气候变化领域集成服务门户(CCPortal): Trends in precipitation chemistry across the U.S. 1985–2017: Quantifying the benefits from 30 years of Clean Air Act amendment regulation

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DOI	10.1016/j.atmosenv.2021.118219
	Trends in precipitation chemistry across the U.S. 1985–2017: Quantifying the benefits from 30 years of Clean Air Act amendment regulation
	McHale M.R.; Ludtke A.S.; Wetherbee G.A.; Burns D.A.; Nilles M.A.; Finkelstein J.S.
发表日期	2021
ISSN	1352-2310
卷号	247
英文摘要	Acid rain was first recognized in the 1970s in North America and Europe as an atmospheric pollutant that was causing harm to ecosystems. In response, the U.S. Congress enacted Title IV of the Clean Air Act Amendments (CAA) in 1990 to reduce sulfur and nitrogen emissions from fossil fuel burning power plants. This study reports trends in wet-precipitation chemistry in response to emissions reductions implemented as part of the CAA. Trends were calculated for sulfate (SO4), nitrate (NO3) and ammonium (NH4) from 1985 to 2017 at 168 stations operated by the National Atmospheric Deposition Program (NADP); stations were divided into 9 regions across the United States. Trend analyses were conducted for three time periods: Period 1 (1985–1999), Period 2 (2000–2017), and the entire study period (1985–2017). Seasonal and regional Kendall trend analyses reveal significant decreasing trends in mean wet-precipitation SO4 concentrations in all 9 regions during the entire study period. The largest decreasing trends in monthly mean SO4 precipitation-weighted concentrations were measured in the Mid-Atlantic (−1.29 μeq/l/yr), Midwest (−1.15 μeq/l/yr), and Northeast regions (−1.10 μeq/l/yr). The trends in monthly mean NO3 concentrations were not as strong as those for SO4, but all of the regions had significant decreasing trends in NO3 and again the Mid-Atlantic (−0.53 μeq/l/yr), Midwest (−0.44 μeq/l/yr), and Northeast regions (−0.50 μeq/l/yr) had the strongest trends. Trends were steepest during Period 2 for SO4 and NO3, in fact for NO3 86% of the stations had significant decreasing trends during Period 2 while only 8% of the stations had significant decreasing trends during Period 1. The stations with the highest concentrations of SO4 and NO3 at the beginning of the study had the strongest decreasing trends and the relations were stronger during Period 2 than Period 1. For NH4, 22% of the stations had statistically significant increasing trends in concentration during Period 1. The largest increasing trends in wet-precipitation NH4 concentration occurred in the North-Central region during Period 1, Period 2 and throughout the entire study. By comparison, NH4 trends in the Rocky-North and Rocky-South regions were about half as steep and trends in the South-Central and Midwest regions were about one-third as steep. We compared trends in SO4 and NO3 concentrations from NADP stations to emissions of sulfur dioxide and nitrogen oxides, respectively to determine whether there was a relation between emissions and wet-precipitation concentration trends within proximity to NADP stations. There was a statistically significant relation (r2 = 0.62–0.69, p < 0.01) between the trend in SO4 concentrations at individual NADP stations and total and mean sulfur dioxide (SO2) emissions from power plants within a range of 750 km and 1000 km from each station. There were also significant relations between NO3 concentration trends at NADP stations and power plant emissions of nitrogen oxides, but they were not nearly as strong (r2 = 0.18–0.36, p < 0.01) as those for SO4 and were strongest for emissions within a range of 1000 km and 1500 km from each NADP station. Decreases in wet-precipitation SO4 concentrations were more consistent across regions and through time than decreases in NO3 and SO4 trends were more closely linked to stationary emissions sources than NO3 trends. There were statistically significant increases in NH4 wet-precipitation concentrations, as have been reported in previous studies, but this study found that those increases were strongest during Period 1 and were not consistent across the United States. During the first 3 years of the study period, wet-precipitation acidity was dominated by SO4 in 8 of the 9 regions; by 2017 NO3 dominated the acidity of wet-precipitation in 7 of the 9 regions. There has also been a downward shift in the NO3:NH4 ratio of wet-precipitation as the emissions of nitrogen oxides have declined while ammonia emissions have remained essentially constant. This shift has resulted in an increase in wet-precipitation total nitrogen concentrations in 7 of the 9 regions and indicate that efforts to control NH3 emissions will become increasingly important as emissions of nitrogen oxides continue to decline. © 2021
关键词	Ammonium Atmospheric deposition Nitrate Sulfate
语种	英语
scopus关键词	Acid rain; Air quality standards; Ammonia; Atmospheric chemistry; Fossil fuel power plants; Fossil fuels; Meteorological problems; Nitrogen oxides; Sulfur dioxide; Atmospheric pollutants; Clean air act amendments; Concentration trends; Emissions reduction; National atmospheric deposition programs; Power-plant emissions; Precipitation chemistry; Stationary emissions; Air pollution control; ammonia; nicotinamide adenine dinucleotide phosphate; nitrate; nitrogen oxide; sulfate; sulfur dioxide; acid rain; atmospheric pollution; concentration (composition); emission control; pollution policy; precipitation (climatology); precipitation quality; quantitative analysis; regulatory approach; temporal variation; trend analysis; acidity; act; air; Article; atmospheric deposition; calculation; controlled study; electric power plant; nitrogen concentration; precipitation; priority journal; trend study; United States; Europe; Mid-Atlantic States; Midwest; United States
来源期刊	ATMOSPHERIC ENVIRONMENT
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/248596
作者单位	U.S. Geological Survey, New York Water Science Center, 425 Jordan Road, Troy, NY 12180, United States; U.S. Geological Survey, Retired, Denver, CO 80225, United States; U.S. Geological Survey, Hydrologic Networks Branch, W. 6th Ave. Kipling Street, Denver, CO 80225, United States
推荐引用方式 GB/T 7714	McHale M.R.,Ludtke A.S.,Wetherbee G.A.,等. Trends in precipitation chemistry across the U.S. 1985–2017: Quantifying the benefits from 30 years of Clean Air Act amendment regulation[J],2021,247.
APA	McHale M.R.,Ludtke A.S.,Wetherbee G.A.,Burns D.A.,Nilles M.A.,&Finkelstein J.S..(2021).Trends in precipitation chemistry across the U.S. 1985–2017: Quantifying the benefits from 30 years of Clean Air Act amendment regulation.ATMOSPHERIC ENVIRONMENT,247.
MLA	McHale M.R.,et al."Trends in precipitation chemistry across the U.S. 1985–2017: Quantifying the benefits from 30 years of Clean Air Act amendment regulation".ATMOSPHERIC ENVIRONMENT 247(2021).