In a paper published in the prestigious journal Science, CERN’s CLOUD experiment has shown that biogenic vapours emitted by trees and oxidised in the atmosphere have a significant impact on the formation of clouds, thus helping to cool the planet.
Organic vapor concentrations such as Pinanediol were measured in the CLOUD chamber by scientists from the “Institut für Ionenphysik und Angewandte Physik” of the University of Innsbruck using advanced PTR-TOF technology, allowing for real-time quantification of tiniest concentrations of volatile organic compounds (VOCs).
Biogenic vapours join another class of trace vapours, known as amines, that have previously been shown by CLOUD to cluster with sulphuric acid to produce new aerosol particles in the atmosphere. Amines, however, are only found close to their primary sources such as animal husbandry, whereas alpha-pinene is ubiquitous over landmasses. This latest result from CLOUD could therefore explain a large fraction of the birth of cloud seeds in the lower atmosphere around the world. It shows that sulphuric acid aerosols do indeed have a significant influence on the formation of clouds, but they need the help of trees.