Project at a Glance

Title: 21-day exposure to mixed air pollutants: effects on lung airways and macrophages

Principal Investigator / Author(s): Phalen, Robert

Contractor: Air Pollution Health Effects Laboratory, Department of Community and Environmental Medicine, UC Irvine

Contract Number: A6-126-33

Research Program Area: Health & Exposure

Topic Areas: Health Effects of Air Pollution


The effects of exposure to a seven-component pollutant atmosphere on epithelial permeability and macrophage functions in rats have been studied. The components of this atmosphere (0.30 ppm ozone + 1.2 ppm nitrogen dioxide + 2.5 ppm sulfur dioxide 3 + 0.27 mg/m3 ammonium sulfate + 0.22 mg/m ferric sulfate + 0.004 mg/m3 manganese sulfate + 0.15 mg/m ferric oxide) were selected in order to model the oxidant and sulfate containing air pollutant mixtures which are common in the South Coast Air Basin of southern California. Separate groups of rats were exposed fours hours per day to either purified air or the seven-component atmosphere for either 7 or 21 consecutive days. Results indicate that statistically significant (p < 0.05) effects on macrophage functions (Fc receptor activity and phagocytic activity) were observed in rats exposed to the seven-component mixture for both 7 and 21 days, with more pronounced effects seen in the group exposed for 21 days. In both cases the effects persisted up to 96 hours post-exposure. No statistically significant effects on nasal or bronchoalveolar epithelial permeability were found in either the 7-day or 21-day exposure groups. These findings indicate that a mechanism by which the deep lung is cleansed of particulate debris, macrophage activity, is compromised throughout the period of repeated exposure to the seven-component atmosphere, while no significant effects on the integrity of the airway epithelia are produced. Although the changes seen in macrophage function are not a disease per se, they indicate damage to an important defense mechanism that must function efficiently in order to maintain health.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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