Sources of particulate matter and effects (IMAGE) American Institute of Physics Caption Sources of particulate matter and effects they can have on the human mucosal system Credit Matthias Marczynski Usage Restrictions Journalists may use this image only with appropriate credit. License Original 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.