[Atmospheric pollution, mechanisms of action of inhaled toxicants].
Inhaled pollutants have different targets in the airways. Ozone is able to induce lesions in all parts of the respiratory tract, SO2 is mainly solubilized in proximal airways while particles have a major retention time in the deep lung. Ciliated cells and pneumocytes 1 are the most sensitive targets. Besides the direct toxic effects of the pollutants on the target cells, amplification loops are easily switched on by indirect action of inflammatory mediators (Arachidonic acid cascade, PAF, cytokines, histamine, proteins secreted by eosinophils, proteases ... ); this is mainly due to the ability of injured epitheliums to recruit rapidly circulating inflammatory cells. Decreasing ventilatory function results mainly from triggering of nerve fibers which results in return in a true neurogenic inflammatory response. Chronical exposures to oxidants, sulfur derived compounds and particles may lead to changes of the homeostatic imbalance of airways cellularity.
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D000280:Administration, Inhalation; D000393:Air Pollutants / Q000009:adverse effects*; D002986:Clinical Trials as Topic; D006801:Humans; D010126:Ozone / Q000009:adverse effects; D012016:Reference Values
D000393:Air Pollutants; D010126:Ozone