Toxicity of nitrogen dioxide

Slade, R., Highfill, J.W., and Hatch, G.E. 1989. Effects of depletion of ascorbic acid or nonprotein sulfhydryls on the acute inhalation toxicity of nitrogen dioxide, ozone, and phosgene. Inhalation Toxicol. 1 261-271. 

Acute inhalation toxicity of nitrogen dioxide, red fuming nitric acid, and white fuming nitric acid. Arch. Ind. Hyg. Occup. Med. 10 418-422. 

Although the lead-chamber processed increased the amount of sulfuric acid that could be produced, it relied on a source of nitrate that usually had to be imported. The process also produced nitric oxide gas (NO), which oxidized to toxic brown nitrogen dioxide (N02) in the atmosphere. To reduce the supply of nitrate required and the amount of nitric oxide produced, Joseph Louis Gay-Lussac (1778-1850) proposed that the nitric oxide be captured in a tower and recycled into the lead chamber. Although Gay-Lussac first proposed this modification to the lead-chamber method around 1830, it was not until the 1860s that John Glover (1801-1872) actually implemented Gay-Lussacs idea with the Glover tower. 

Leaves with symptoms of acute injury usually drop prematurely. Abscission layer development may be stimulated by a rapid reaction of leaves to a high concentration of toxicant, resulting in heavy defoliation without detectable necrosis or chlorosis. Exposure to very high concentrations of nitrogen dioxide, chlorine, or hydrogen chloride may cause extensive defoliation within a few hours. Much lower concentrations may cause gradual development of typical symptoms of senescence, followed by premature dropping of affected leaves. 

When oxides of nitrogen come in contact with water, both nitrous and nitric acids are formed (18) (Table IV). Toxic reactions may result from pH decrease. Other toxic reactions may be a consequence of deamination reactions with amino acids and nucleic acid bases. Another consideration is the reactions of oxides of nitrogen with double bonds (Table IV). The cis-trans isomerization of oleic acid exposed to nitrous acid has been reported (19). Furthermore, the reaction of nitrogen dioxide with unsaturated compounds has resulted in the formation of both transient and stable free radical products (20, 21) (Table V). A further possibility has been raised in that nitrite can react with secondary amines to form nitrosamines which have carcinogenic properties (22). Thus, the possible modes of toxicity for oxides of nitrogen are numerous and are not exhausted by this short list. 

For example, consider an overall equation for the formation of nitrogen dioxide, the toxic pollutant that contributes to photochemical smog and acid rain ... 

Animal experiments indicate nitric oxide to be much less toxic than nitrogen dioxide. However, because of its spontaneous oxidation to highly toxic nitrogen dioxide, nitric oxide should be viewed as a severe health hazard. 

Because of its high acute toxicity, nitrogen dioxide should be handled using the "basic prudent practices" of Chapter 5.C, supplemented by the additional precautions for work with compounds of high toxicity (Chapter 5.D) and compressed gases (Chapter 5.H). In particular, cylinders of nitrogen dioxide should be stored and used in a continuously ventilated gas cabinet or fume hood. 

Adsorption of nitrogen dioxide onto kaolinites produced a small but significant decrease in toxicity to P388Di cells (Robertson et al. 1982). 

Kikugawa K, Hiramoto K, Tomiyama S, Asano Y (1997) P-Carotene effectively scavenges toxic nitrogen oxides nitrogen dioxide and peroxynitrous acid. FEBS Lett 404 175-178 Everett SA, Dennis MF, Patel KB, Maddix S, Kundu SC, Willson RL (1996) Scavenging of nitrogen dioxide, thiyl, and sulfonyl free radicals by the nutritional antioxidant fLcarotene. J Biol Chem 271 3988 3994... 

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