Hydroxyl Radical Concentration (image) University of Bristol Share Print E-Mail Caption This is a model simulation of the hydroxyl radical concentration in the atmosphere. Credit Angharad Stell, University of Bristol. Usage Restrictions None Share Print E-Mail 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.