Chronic Toxicity of NO₂ in Squirrel Monkeys

Abstract

Continuous exposure to 10 and 5 ppm nitrogen dioxide (NO₂) for one and two months, respectively, increased the susceptibility of squirrel monkeys to airborne Klebsiella pneumoniae as demonstrated by mortality and reduced lung clearance of viable bacteria. The respiratory function was also affected by NO₂ exposure. Infectious challenge with influenza virus 24 hours before exposure to 10 ppm was fatal to all monkeys within three days. Infected controls showed symptoms of viral infection but did not succumb to the infection. Exposure to 5 ppm after viral infection produced death in one of three monkeys.