Normal individuals developed pulmonary neutrophilic inflammation and increased blood fibrinogen following inhalation of concentrated ambient particles (CAPS). In this study, we sought to determine how soluble components in CAPS contributed to these changes. We expanded and reanalyzed data from 37 young healthy volunteers from a previous study (Ghio et al., 2000) who were exposed to either filtered air or CAPS. Postexposure bronchoalveolar lavage (BAL) as well as pre- and postexposure venous blood samples was analyzed for cellular and acute inflammatory endpoints. Nine most abundant components in the water-soluble fraction of CAPS were correlated with these endpoints using principal component analysis. We found that a sulfate/Fe/Se factor was associated with increased BAL percentage of neutrophils and a Cu/Zn/V factor with increased blood fibrinogen. The concentrations of sulfate, Fe, and Se correlated highly with PM mass (R > 0.75) while the correlations between PM and Cu/Zn/V were modest (R = 0.2-0.6). These results from controlled human exposure linked specific PM components to pulmonary neutrolphil influx and blood fibrinogen increase, and indicated the soluble components of pollutant particles may differentially affect pulmonary and hematological systems in humans exposed to PM.