Air Filters (IMAGE) University of Münster Caption The scientists carried out the isotope measurements using such air filters. Credit Dorian Zok/LUH Usage Restrictions Please use this picture only in connection with the press release. License Licensed 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.