Changes of precipitation acidity related to sulfur and nitrogen deposition in forests across three continents in north hemisphere over last two decades

Chung-Te Chang; Ci-Jian Yang; Ko-Han Huang; Jr-Chuan Huang; Teng-Chiu Lin

doi:10.1016/j.scitotenv.2021.150552

Changes of precipitation acidity related to sulfur and nitrogen deposition in forests across three continents in north hemisphere over last two decades

Sci Total Environ. 2022 Feb 1;806(Pt 1):150552. doi: 10.1016/j.scitotenv.2021.150552. Epub 2021 Sep 24.

Authors

Chung-Te Chang¹, Ci-Jian Yang², Ko-Han Huang³, Jr-Chuan Huang², Teng-Chiu Lin⁴

Affiliations

¹ Center for Ecology and Environment, Tunghai University, Taichung 40799, Taiwan; Department of Life Science, Tunghai University, Taichung 40799, Taiwan. Electronic address: chungtechang@thu.edu.tw.
² Department of Geography, National Taiwan University, Taipei 10617, Taiwan.
³ Department of Life Science, Tunghai University, Taichung 40799, Taiwan.
⁴ Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan.

PMID: 34844330
DOI: 10.1016/j.scitotenv.2021.150552

Abstract

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 (SO₄^2-)/nitrate (NO₃^-) and ammonium nitrogen (NH₄-N)/nitrate nitrogen (NO₃-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 (SO₂) and nitrogen oxides (NOx) emissions. In contrast, sulfate still plays a dominant role on the acidity of precipitation than nitrate in Asia, and NH₄-N deposition also has a significant contribution in N flux due to increasing trends of ammonia emissions in Southeast Asia.

Keywords: Ammonium; Atmospheric deposition; Calcium; Emission control; Nitrate; Sulfate.

MeSH terms

Air Pollutants* / analysis
Environmental Monitoring
Forests
Nitrogen* / analysis
Sulfur

Substances

Air Pollutants
Sulfur
Nitrogen