The FHWA and EPA collaborated on a research effort to characterize the impact and behavior of particulate matter with aerodynamic diameter less than 2.5 microns (PM2.5) and MSATs near highways. This study was conducted from mid-December 2008 thru mid-December 2009. The preliminary results of this study have been summarized in the Executive Summary and are described in detail in the previous sections of this report.
