Concentration-response relationships of rat lungs to exposure to oxidant air pollutants: A critical test of Haber's Law for ozone and nitrogen dioxide

Thomas R. Gelzleichter, Hanspeter Witschi, Jerold A Last

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Exposure protocols were designed to ask whether lung damage in rats exposed to either ozone or nitrogen dioxide is proportional to dose rate or to cumulative dose. Thus, the response of rats to a constant product of concentration of oxidant air pollutant and time of exposure (C × T) was evaluated for 3-day exposures over a fourfold range of concentrations of ozone (0.2-0.8 ppm) or of nitrogen dioxide (3.6-14.4 ppm) for exposure durations of 6-24 hr per day. The response of rat lungs was quantified by changes in total protein content of lung lavage supernatants or by changes in content of specific cell types in lung lavage pellets. The results of these experiments clearly demonstrate that acute lung damage is a function of cumulative dose (that is, C × T product) for the three highest dose rates tested. However, when exposure duration is extended to include the entire 24-hr period (the lowest dose rate tested), there is a marked attenuation of pulmonary response. Rats were also exposed to mixtures of ozone and nitrogen dioxide with the C × T product held constant. Our results clearly demonstrate that when rats are exposed to combinations of ozone and nitrogen dioxide, lung damage is a function of peak concentration rather than a function of cumulative dose. This deviation from Haber's Law is attributed to a concentration-dependent, synergistic (greater than additive) response to this specific mixture of oxidant air pollutants.

Original languageEnglish (US)
Pages (from-to)73-80
Number of pages8
JournalToxicology and Applied Pharmacology
Volume112
Issue number1
DOIs
StatePublished - 1992

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Nitrogen Dioxide
Air Pollutants
Ozone
Oxidants
Rats
Lung
Bronchoalveolar Lavage
Proteins
Experiments

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology

Cite this

Concentration-response relationships of rat lungs to exposure to oxidant air pollutants : A critical test of Haber's Law for ozone and nitrogen dioxide. / Gelzleichter, Thomas R.; Witschi, Hanspeter; Last, Jerold A.

In: Toxicology and Applied Pharmacology, Vol. 112, No. 1, 1992, p. 73-80.

Research output: Contribution to journalArticle

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