Occupational exposure limits : Criteria document for nitric acid.

In the working environment the exposure will be a combination of nitric acid in gas phase and of nitric acid dissolved in water aerosols (cloud droplets, fog, haze). [...] HN03-vapour is expected to be removed in the extrathoracic region and upper airways, whereas the exact deposition pattern for HN03 dissolved in aerosols, is related to the pure vapour as well as the particles and depends upon the rate at which vapour is released from the droplets during the airway passage thereby influencing the aerodynamic diameter of the particle. [...] Exposure to a low concentration of the acid provokes mild irritation to the eyes and throat, a dry cough and tightness of the chest. [...] The recovery of persons exposed to mixtures of nitric acid and nitrogen oxides seems to depend upon the duration and amount of exposure. [...] The severity of the inflammation is related to the amount and concentration of the acid, and the amount of residual gastric content (Boikan and Singer, 1930; Adams and Skucas, 1980; Subbarao et al., 1988; Ipsen, 1893).