Effects of exercise exposure on toxic interactions between inhaled oxidant and aldehyde air pollutants
Respiratory tract injury resulting from inhalation of mixtures of ozone (O3) and nitrogen dioxide (NO2) and of O3 and formaldehyde (HCHO) was studied in Sprague-Dawley rats under exposure conditions of rest and exercise. Focal inflammatory injury induced in lung parenchyma by O3 exposure was measured morphometrically and HCHO injury to the nasal respiratory epithelium was measured by cell turnover using tritium-labeled thymidine. Mixtures of O3 (0.35 or 0.6 ppm) with NO2 (respectively 0.6 or 2.5 ppm) doubled the level of lung injury produced by O3 alone in resting exposures to the higher concentrations and in exercising exposures to the lower concentrations. Formaldehyde (10 ppm) mixed with O3 (0.6 ppm) resulted in reduced lung injury compared to O3 alone in resting exposures, but exercise exposure to the mixture did not show an antagonistic interaction. Nasal epithelial injury from HCHO exposure was enhanced when O3 was present in a mixture. Mixtures of O3 and NO2 at high and low concentrations formed respectively 0.73 and 0.02 ppm nitric acid (HNO3) vapor. Chemical interactions among the oxidants, HNO3, and other reaction products (N2O5 and nitrate radical) and lung tissue may be the basis for the O3-NO2 synergism. Increased dose and dose rate associated with exercise exposure may explain the presence of synergistic interaction at lower concentrations than observed in resting exposure. No oxidation products were detected in O3-HCHO mixtures, and the antagonistic interaction observed in lung tissue during resting exposure may result from irritant breathing pattern interactions.
- Research Organization:
- Univ. of California, Irvine (USA)
- OSTI ID:
- 6554164
- Journal Information:
- J. Toxicol. Environ. Health; (United States), Journal Name: J. Toxicol. Environ. Health; (United States) Vol. 25:2; ISSN JTEHD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Formaldehyde dose-response in healthy nonsmokers
Transport of macromolecules and particles at target sites for deposition of air pollutants
Related Subjects
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR POLLUTION
ALDEHYDES
ANIMALS
BIOLOGICAL EFFECTS
CHALCOGENIDES
DOSE-RESPONSE RELATIONSHIPS
EXERCISE
FORMALDEHYDE
INHALATION
INTAKE
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
OZONE
POLLUTION
RATS
RESPIRATORY SYSTEM
RODENTS
SENSITIVITY
SYNERGISM
TOXICITY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES