Chemical Sensor (image) University of Illinois at Urbana-Champaign Caption The device uses a printed array smaller than a postage stamp made up of nanoporous pigments that change color in response to their chemical environment. The color differences are shown for a few representative poison gases Credit Photo courtesy of Kenneth Suslick, University of Illinois. Usage Restrictions Photo may be used only with stories about the research described in the news release. Please credit: Photo courtesy of Kenneth Suslick, University of Illinois. 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.