||Health Effects of Short-Term Inhalation of Nitrogen Dioxide and Ozone Mixtures.
Ehrlich, Richard ;
Findlay, J. C. ;
Fenters, J. D. ;
Gardner., D. E. ;
||IIT Research Inst., Chicago, Ill.;Health Effects Research Lab., Research Triangle Park, N.C. Clinical Studies Div.
||EPA/600/J-77/099; EPA-68-02-1267 ;EPA-68-02-2274; EPA/600/J-77/099;
Nitrogen dioxide ;
Respiratory diseases ;
Bacterial diseases ;
Infectious diseases ;
Laboratory animals ;
Synergistic effects of air pollutants ;
Air pollution effects(Animals)
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The effects of single and multiple daily 3-hour exposures to nitrogen dioxide (NO2) and ozone (O3) mixtures on the resistance to streptococcal pneumonia were investigated. The concentrations of NO2 ranged from 1.5 to 5.0 ppm, and those of O3, from 0.05 to 0.5 ppm. The effect of a single exposure to the mixture was additive, whereby the excess mortality rates were equivalent to those induced by the inhalation of each individual pollutant. The ability to clear inhaled bacteria from the lungs was diminished in mice exposed to the NO2-O3 mixtures for 3 hours. This impairment was manifested by the increased frequency of isolation of Streptococcus from the lungs for up to 6 days after the respiratory challenge. Excess mortalities observed after 20 daily 3-hour exposures suggested that a synergistic effect might be present upon repeated inhalation of pollutant mixtures, that made them more effective in reducing resistance to respiratory infection. The results emphasize the need for the establishment of primary air quality standards for short-term NO2 exposures. (Copyright (c) 1977 Academic Press, Inc.)