(IMAGE) Paul Scherrer Institute Caption A study by André Prévôt (left) and Imad El Haddad from the Laboratory for Atmospheric Chemistry at the Paul Scherrer Institute PSI provides a basis for decision-making to improve the living conditions of millions of people. Credit Paul Scherrer Institute/Mahir Dzambegovic Usage Restrictions PSI provides image and/or video material free of charge for media coverage of the content of the above text. Use of this material for other purposes is not permitted. This also includes the transfer of the image and video material into databases as well as sale by third parties. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.