Petter Ljungman, Karolinska Institutet (IMAGE) Karolinska Institutet Caption This is Petter Ljungman, researcher at the Institute of Environmental Medicine at Karolinska Institutet in Sweden. Credit Stefan Zimmerman Usage Restrictions None 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.