Original reports of 9,500 WTC responders examined between July 2002 and April 2004, noted abnormal pulmonary function results in one-third of participants. Further studies of this population have demonstrated persistent changes in pulmonary function tests 9 years after exposure (2010 Annual Report on 9/11 Health). Numerous complex interactions between pulmonary and cardiovascular systems exist. In fact, at the molecular level, evidence supports an integral role for reactive oxygen species (ROS)-dependent pathways in the instigation of pulmonary oxidative stress, systemic pro-inflammatory responses, vascular dysfunction and atherosclerosis.