Meteorologically normalised long-term trends of atmospheric ammonia (NH 3 ) in Switzerland/Liechtenstein and the explanatory role of gas-aerosol partitioning.

Autor: Grange SK; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Zürich, Switzerland; Wolfson Atmospheric Chemistry Laboratories, University of York, York YO10 5DD, United Kingdom. Electronic address: stuart.grange@empa.ch., Sintermann J; Office for Waste, Water, Energy and Air - AWEL, Canton Zürich, Stampfenbachstrasse 12, 8090 Zürich, Switzerland., Hueglin C; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Zürich, Switzerland.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2023 Nov 20; Vol. 900, pp. 165844. Date of Electronic Publication: 2023 Jul 29.
DOI: 10.1016/j.scitotenv.2023.165844
Abstrakt: Ammonia (NH 3 ) is an important atmospheric pollutant and despite significant management efforts, trends of NH 3 concentrations have not shown progressive decreases over the last few decades across much of Europe. To investigate this issue, long-term NH 3 concentrations from passive sampling tubes were analysed at 32 locations across Switzerland and Liechtenstein. A trend analysis controlling for changes in meteorology employing generalised additive models (GAMs) between 2000 and 2021 showed that 29 of the 32 (91 %) sites experienced no significant change or increasing NH 3 concentrations with the greatest trend being 0.17 μgm -3 y -1 . These results conflict with an indicated 13 % reduction in NH 3 emissions from the Swiss emission inventory. The sensitivity of the NH 3 -ammonium (NH 4 + ) system to reductions of NH 3 's acidic sinks (mostly in the form of nitric and sulfuric acids) was investigated with thermodynamic equilibrium modelling to explain this disconnect. The simulations indicated that the reductions in NH 3 's acidic sinks resulted in less NH 4 + transformation, thus increasing the NH 3 /NH x ratio and this process has compensated for the reduction in NH 3 emissions. The average effect of the sink reductions was an increase of 0.9 μgm -3 in NH 3 between 2004 and 2021. Increases in the NH 3 /NH x ratio have likely occurred in many European countries due to reductions of acidic precursor emissions and will have consequences for reactive nitrogen deposition and alter import-export budgets among neighbouring regions and countries.
Competing Interests: Declaration of competing interest Stuart K. Grange reports financial support was provided by Federal Office for the Environment.
(Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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