Precipitation chemistry: Long-term Changes in Central Europe

Precipitation is an important mediator between the atmosphere and the Earth's surface. As a wet-only part of atmospheric deposition, it maintains transfer of water, nutrients and air pollutants into ecosystems. Precipitation chemistry reflects ongoing atmospheric processes (Seinfeld and Pandis, 2006), and given its importance, its composition is regularly observed and measured at global, regional and national scales.

This contribution presents long-term changes in precipitation chemistry observed within a nationwide monitoring network in the Czech Republic, which is run by the Czech Hydrometeorological Institute. Point-wise data from station measurements from 1990 to 2024 were analysed, and nationwide averages from stations with simultaneous major ion measurements were explored.

Our results clearly demonstrate significant changes over the past three decades, evident in the relative proportions of major pollutants such as sulphates, nitrates and ammonium ions. These changes (i) reveal substantial changes in atmospheric composition with respect to changing emission levels; (ii) suggest changes in atmospheric chemistry; and (iii) indicate potential impacts on ecosystems and the environment.

Changes in precipitation chemistry are driven by changes in the absolute amounts and relative proportions of pollutant emissions and ongoing climate change.  Due to uneven reductions in SO₂ and NOx emissions, the relative proportions of SO₄²⁻, NO₃⁻ and NH₄⁺ in precipitation have changed. These changes are evident not only in the levels of individual pollutants, but also in the ratios of these pollutants over time.

Further detailed information can be found, for example, in Hůnová et al. (2024) and Hůnová and Škáchová (2025).

 

 

Hůnová, I., Brabec, M., Malý, M., 2024. Major ions in Central European precipitation: Insight into changes in NO₃₋/SO₄²⁻, NH₄⁺/NO₃⁻ and NH₄⁺/SO₄²⁻ ratios over the last four decades. Chemosphere 349, 140986.

Hůnová, I., Škáchová, H., 2025. Chemické složení atmosférických srážek je indikátorem výrazných změn v našem ovzduší, Chemické listy, 119, 533–540.

Seinfeld, J.H., Pandis, S.N., 2006. Atmospheric Chemistry and Physics. From Air Pollution to Climate change. Second edition. John Wiley & Sons, Inc., Hoboken.