NITROGEN OXIDES

Nitric oxide and nitrogen dioxide are considered to be the most important of the oxides of nitrogen (NOx) in terms of public health concern. This chapter identifies, evaluates, and characterizes risk factors that address the question of what populations and life stages are at increased risk of health effects associated with exposure to NOx along with the other gas-phase and particulate matter components the complex and varying pollutant mixtures in ambient air. It first discusses the emission sources of NOx. The chapter focuses on the dosimetry, health effects, and exposure aspects of nitrogen dioxide, nitric oxide, nitric/nitrous acid, and inorganic nitrates. Some studies have indicated that chronic exposure to nitrogen dioxide is associated with increased risk of all-cause mortality and suggested a specific association of the gas with cardiopulmonary mortality as well.