Toxicity of nitrogen dioxide: an introduction

Many questions, needed to advance our understanding of the mechanism of injury from high-level NO2, remain unanswered to date. This is partly due to the limited interest in the toxicity of high-level exposures, and partly due to the public pressure and interest to study the effects of low- (environmental) levels. However, the effects of exposure to high-level NO2 are of great interest to the military since high levels of NO2 may be found in combat situations. It is also important to the civilian section in occupational settings where accidents may occur as in silo filler accidents. To fill this gap in knowledge, the Department of Respiratory Research, Division of Medicine at Walter Reed Army Institute of Research took the initiative and convened a panel of experts in a symposium to discuss in depth the effects of exposure to high-level nitrogen dioxide. The symposium goals were to address the issues beginning from the chemistry of NO2 molecule, to the dosimetry of its uptake (isolated lung), to the biological effects of exposure in vivo in small animals (rats), large animals (sheep), and finally in the most relevant species, humans.