Indirect Voltammetric Method for Determination of Nitrogen Dioxide in the Ambient Atmosphere

A hydrodynamic voltammetrric method was developed to determine the concentration of atmospheric nitrogen dioxide. Air samples were collected in 0.1M NaOH scrubbing solution which converts NO2 to NO2 -and NO3 -in a fixed stoichiometric ratio. The produced NO2 -ion was analyzed by hydrodynamic voltammetry at a rotating disk gold electrode. A calibration curve was established by plotting the anodic steady state current (is) versus NO2 -concentration. The calibration curve showed a remarkable linearity between the steady state current for NO2 - oxidation and NO2 - ion concentration (correlation coefficient = 0.9975). The Validity of the method was checked against spectrophotometric determination of NO2 -. The agreement between the two methods was confirmed (R2 = 0.9965). The applicability of the method to real-life analysis was established by estimation of NO2 concentration in ambient air of three districts in Amman. The results indicated that the atmospheric concentration of NO2 in the three districts conforms to the international and national atmospheric clean air standards.