Toxicological interactions between ozone, aerosols, and fine particles in the lungs
- Health Canada, Ottawa (Canada)
- Univ. of California, Irvine, CA (United States); and others
The effects of common ambient air pollutants (O{sub 3}, acid vapours & aerosols, NO{sub 2}, particles) were studied on the respiratory system in animal models. Acute exposure of rats to O{sub 3} produces a rapid-shallow breathing pattern, reflecting lower respiratory tract irritation, and an increased permeability of the air-blood barrier due to cellular injury. With repeated exposure, eg. over the course of five days, the changes become less pronounced, a phenomenon which has been referred to as tolerance development, or adaptation. Simultaneous inhalation of O{sub 3} and acidic aerosols did not result in adaptation. Rats were exposed 4 hours per day for 1 day or 5 consecutive days to: clean air; ozone (0.2 and 0.4 ppm 03); a low mixture (20 ppb HNO{sub 3}; 100 {mu}g/m{sub 3} H{sub 2}SO{sub 4}; 0.2 ppm O{sub 3}, 0.3 ppm NO{sub 2}; 50 {mu}g/m{sup 3} carbon); or a high mixture (40 ppb HNO{sub 3}; 500 {mu}g/m{sup 3} H{sub 2}SO{sub 4}; 0.4 PPM O{sub 3}, 0.6 ppm NO{sub 2}; 250 {mu}g/m{sup 3} carbon). The mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of the fine, insoluble carbon particles were 0.5 pm and 2.0, respectively. In contrast to the effect of O{sub 3} alone, rapid shallow breathing persisted after repeated exposure to the mixture over 5 consecutive days. Lung lesions were increased after exposure to the high mixture concentration, by comparison to ozone alone, at both day 1 and day 5. Inhalation of the mixture also resulted in a greater depression of Fc-receptor binding capacity of alveolar macrophages after 1 day and 5 days. Guinea pigs exposed to sulphuric acid (14, 20 or 50 mg/m{sup 3} H{sub 2}SO{sub 4}, 4 hours) showed significant increases in tidal volume with prolonged expiratory times using an indirect plethysmograph method. By 24 hours post-exposure, slightly increased respiratory frequencies and significantly decreased tidal volumes and minute ventilation rates were observed compared to immediately post-exposure.
- OSTI ID:
- 166561
- Report Number(s):
- CONF-9510126-; TRN: 95:008181-0052
- Resource Relation:
- Conference: Annual meeting of the American Association for Aerosol Research, Pittsburgh, PA (United States), 9-13 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of American Association for Aerosol Research (AAAR) `95; PB: 464 p.
- Country of Publication:
- United States
- Language:
- English
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