Gas phase ammonia is plays an important role in the formation of atmospheric aerosol particles. These particles may affect cloud properties which, in turn, modulate Earth surface temperatures and precipitation. However, the critical role of ammonia has not been unambiguously demonstrated. Underlaying challenge is that reliable ammonia measurements are extremely difficult, and little is known about concentrations, sources and fate of ammonia especially in the Arctic atmosphere. In this project, ammonia is measured using novel technology from subarctic Lapland to high Arctic Svalbard and northern Greenland. Simultaneous and diverse measurements of other relevant vapours and new particles allow us to quantify the concentrations and sources of ammonia and resolve the aerosol particle formation mechanisms. Arctic climate and environment are changing fast. Resolving the role of ammonia in Arctic climate system helps understanding the present and predicting the future climate.

2025

2029