This International Standard specifies a chemiluminescence method for the determination of the mass concentration of nitrogen oxides present in ambient air. The method is applicable to the determination of the mass concentration of nitrogen monoxide present in ambient air up to approximately 12,5 mg/m^(3) and of nitrogen dioxide up to approximately 19 mg/m^(3) respectively11 at 25 °C and 101,3 kPa. For interférants, see 6.6.