Pollution in libraries has always been an issue for library patrons and staff alike. Research on major library pollutants goes back to 1916, when an analysis of dust collected in a vacuum cleaner from the bookshelves of Rensselaer Polytechnic Institute Library in Troy, NY, was conducted. The analysis under the microscope showed human hair, wool, cotton, fly wings, leather, iron, aluminum, calcium, silicon, and a very high content of carbon and nitrogen. But the most striking finding in that study was the presence of a bacterium which came probably from the sneezing and coughing of library patrons. This organism survived under the same conditions as those causing diphtheria, cholera, typhoid fever, and tuberculosis – all deadly diseases at that time. In modern libraries the pollution issue is more complex.