Toxicological interactions between ozone, aerosols, and fine particles in the lungs

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:166561

Bjarnason, S G; Vincent, R ^[1]; Kleinman, M T ^[2]

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1. Health Canada, Ottawa (Canada)
2. 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--
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ACUTE EXPOSURE
AEROSOLS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL ADAPTATION
CHRONIC EXPOSURE
GUINEA PIGS
INHALATION
INTERACTIONS
LUNGS
MIXTURES
OZONE
RATS
RESPIRATORY SYSTEM
SULFURIC ACID
TOLERANCE