Pollution in Asia from 2004-2005 (IMAGE) University of California - San Diego Caption The polluting effects of cooking using biomass like wood or cow dung in south Asia are illustrated through a measurement of aerosol optical depth, a way of measuring the quantity of pollutants in the air by the relative ability of light to penetrate through them. This representation shows reconstructed levels of pollution from 2004 and 2005 with the effects of biofuel cooking removed. Credit Scripps Institution of Oceanography, UC San Diego 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.