Personal Exposures to Acidic Aerosols and Gases

Abstract

Exposures to aerosol strong H+, SO42-, NH4+, NO3-, NO2-, and the gaseous pollutants SO2, HNO3, HNO2, and NH3 were monitored in the metropolitan Boston area with a personal annular denuder/filter pack sampling system. The personal exposure measurements were compared to measurements collected at a centrally located ambient monitoring site. Concentrations of acidic aerosols and gases measured by personal monitoring were found to differ significantly from those measured at the fixed outdoor location. Personal exposures to aerosol strong H+ were slightly lower than concentrations measured at the stationary site due to the neutralization of acidic particles and their incomplete penetration into indoor environments. Concentrations of SO42- and NH4+ measured by personal monitoring were similar to those measured by the fixed location ambient monitor. Personal measurements of SO2 and HNO3 were much lower than those measured outdoors, reflecting deposition of these gases on indoor surfaces. The formation of HNO2 via reactions of nitrogen oxides on indoor surfaces resulted in personal exposures to HNO2 that were substantially higher than outdoor concentrations. Personal exposures to the basic gas, NH3, were also higher than ambient measurements. To our knowledge, this pilot study represents the first use of annular denuders for personal exposure monitoring and promises to open up a new area of personal exposure sampling techniques. The results of this study support the use of personal monitoring to determine human exposures. By applying the personal monitoring techniques used in this study to representative samples, it will be possible to determine population exposures to acidic aerosols and gases. © 1989, American Chemical Society. All rights reserved.