Smog cloud in Normandy. (IMAGE) Helmholtz-Zentrum Dresden-Rossendorf Caption Smog cloud in Normandy. Credit G. Mannaerts, CC BY-SA 4.0 (https://commons.wikimedia.org/wiki/Category:Smog?uselang=de#/media/File:Ciel_du_Havre_04.JPG) Usage Restrictions CC BY-SA 4.0 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.