Studies on the biological effects of nitrogen oxides and photochemical oxidants.

The animal studies in mice resulted as follows. Long-term exposure to NO2 at or above 0.5 ppm affected primarily the respiratory organs. The pulmonary effect of NO was slighter than NO2. Nitrosylhemoglobin formation in vivo was much smaller than in vitro strong affinity of NO with hemoglobin. The components other than O3 contained in the photochemically formed oxidant mixtures enhanced the effect of O3 alone. Symptoms of the patients seriously injured by photochemical smog in Japan suggested the different type in quality from the Los Angeles-type smog.