Air pollution is a diverse and dynamic mixture of gaseous and
particulate matter, limiting our understanding of associated adverse health outcomes. The biological effects of two simulated
smog atmospheres (SA) with different compositions but similar air quality health indexes were compared in a nonobese diabetic rat model (Goto-Kakizaki, GK) and three mouse immune models (house dust mite (HDM)
allergy, antibody response to heat-killed pneumococcus, and resistance to
influenza A
infection). In GK rats, both SA-PM (high
particulate matter) and SA-O3 (high
ozone) decreased
cholesterol levels immediately after a 4-h exposure, whereas only SA-O3 increased airflow limitation. Airway responsiveness to
methacholine was increased in HDM-allergic mice compared with nonallergic mice, but exposure to SA-PM or SA-O3 did not significantly alter responsiveness. Exposure to SA-PM did not affect the
IgM response to pneumococcus, and SA-O3 did not affect virus titers, although inflammatory
cytokine levels were decreased in mice infected at the end of a 7-day exposure. Collectively, acute SA exposures produced limited health effects in animal models of metabolic and
immune diseases. Effects of SA-O3 tended to be greater than those of SA-PM, suggesting that gas-phase components in photochemically derived multipollutant mixtures may be of greater concern than secondary organic
aerosol PM.