There is a recognized need to identify the potential impact of air pollution exposure on the health of military personnel deployed to Southwest Asia (SWA). The exposure characterization reported by Engelbrecht et al. in this issue summarizes the results of a remarkable effort to conduct environmental sampling at locations where US military personnel are deployed in support of Operation Enduring Freedom and Operation Iraqi Freedom. This is an important first step in better understanding the relationship between the health of soldiers deployed in SWA and air pollution in the area of operations. We discuss here what is currently known about the effects of particulate matter (PM) on human health, focusing on the limited evidence specific to US military personnel, and outline current and planned efforts to utilize sampling data to assess health outcomes in deployed military populations.