Center for Ecology and Environment, Tunghai University, Taichung 40799, Taiwan; Department of Life Science, Tunghai University, Taichung 40799, Taiwan.
Department of Geography, National Taiwan University, Taipei 10617, Taiwan.
Sci Total Environ. 2022 Feb 1;806(Pt 1):150552. doi: 10.1016/j.scitotenv.2021.150552. Epub 2021 Sep 24.
Through synthesizing bulk precipitation chemistry in forest sites (n = 128) from three monitoring networks, (NADP in Northern America, EMEP in Europe, and EANET in East Asia), this study quantifies the temporal changes of precipitation acidity and its dominant acidifying agents over the last two decades. Results show distinct declines of sulfate and nitrate depositions and increases of precipitation pH in northeast America and central and east Europe, but not in Asia during 1999 and 2018. The decreases of sulfate and nitrate depositions likely reflect the long-term effort of pollutant emission controls. The temporal pattern of sulfate (SO)/nitrate (NO) and ammonium nitrogen (NH-N)/nitrate nitrogen (NO-N) equivalent ratios indicate that acid rain in the NADP and EMEP have transitioned from sulfate-dominated to nitrate-dominated, and the DIN deposition has shifted from nitrate-dominated to ammonium-dominated in recent years, owing to reductions of sulfur dioxides (SO) and nitrogen oxides (NOx) emissions. In contrast, sulfate still plays a dominant role on the acidity of precipitation than nitrate in Asia, and NH-N deposition also has a significant contribution in N flux due to increasing trends of ammonia emissions in Southeast Asia.
通过综合三个监测网络（北美 NADP、欧洲 EMEP 和东亚 EANET）中 128 个森林站点的批量降水化学数据，本研究量化了过去二十年降水酸度及其主要酸化剂的时间变化。结果表明，1999 年至 2018 年期间，美国东北部和中欧、东欧的硫酸盐和硝酸盐沉积显著减少，而亚洲地区则没有明显变化。硫酸盐和硝酸盐沉积的减少可能反映了污染物排放控制的长期努力。硫酸盐（SO）/硝酸盐（NO）和铵氮（NH-N）/硝酸盐氮（NO-N）当量比的时间模式表明，由于二氧化硫（SO）和氮氧化物（NOx）排放量的减少，NADP 和 EMEP 的酸雨已经从硫酸盐型转变为硝酸盐型，近年来 DIN 沉积也已经从硝酸盐型转变为铵盐型。相比之下，亚洲地区的降水酸度仍主要由硫酸盐决定，而硝酸盐的作用相对较小，由于东南亚氨气排放量的增加趋势，NH-N 沉积对氮通量也有显著贡献。
