LAC - Laboratory of Atmospheric Chemistry
The Laboratory of Atmospheric Chemistry (LAC), established 1 January 2000, is a laboratory of the Energy and Environment Research Division (ENE) at the Paul Scherrer Institute (PSI).
Understanding the processes determining the gas and aerosol chemistry and aerosol physics in the atmosphere in order to determine (1) the impact of energy use on the atmosphere and (2) the impact of pollution on air quality, human health, local weather and climate change.
Our laboratory consists of four interacting groups that operates cutting-edge facilities and instrumentations in the lab and in the field. We run three National facilities, two ambient observatories and an atmospheric chamber facility, that are foreseen to be included in the ACTRIS European research infrastructure. We study the impact of anthropogenic air pollution across environments ranging from cities in Europe and developing countries (e.g. India and China) to pristine areas (e.g. in polar regions and in the free troposphere). We are continuously measuring key climate variables relevant for aerosol properties at the landmark high-alpine Jungfraujoch research site in Switzerland. We simulate the processes occurring in the atmosphere in our smog chamber facility and during experiments at the CLOUD chamber at CERN. Field and laboratory data are interpreted and air pollution sources are quantified with numerical and statistical models. We collaborate with toxicologists, epidemiologists and medical doctors to understand the impact of air pollution on health.
News & Highlights
Clouds consist of cloud droplets that are formed from tiny particles floating in the atmosphere. How these particles develop, however, largely remains a mystery. The formation of particles from amines and sulphuric acid has now been described for the first time à a milestone in atmospheric research.
Atmospheric aerosols exert an important influence on climate1 through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN.
Data of the Paul Scherrer Institute from the High-Alpine Research Station Jungfraujoch yield important information.The eruption of the volcano Eyjafjallajokull in Iceland has stalled flight traffic in large parts of Europe. Decision makers had to base their decisions mainly on model calculations for the volcanic plume dispersion. How dangerous is this volcanic ash layer for planes?
Up to the present time, the nucleation or new formation of particles in the atmosphere has been a great enigma. Until recently, research was based on the assumption that sulphuric acid played the central role in particle formation. However, laboratory experiments and field tests have consistently provided conflicting results. In the lab, considerably higher concentrations of sulphuric acid are required for nucleation to take place than in the atmosphere itself. Now scientists from the Paul Scherrer Institute (PSI) have found out the cause for these conflicting results from their smog chamber. These findings will advance climate research to a significant degree.