Spectrometric Determination of NO2 in Ambient Air and its Control

Increasing concern over the air pollution has forced the man to develop the new technology for the better quality of life. In modern world, air pollution does not need any introduction. One of the major factors responsible for such degradation in the quality of life is air pollution. However, chief among them are carbon monoxide, sulphur dioxide, nitrogen oxides, ozone, etc. Nitrogen dioxide causes acute bronchitis at 0.1 ppm level and increased exposure for 30 minutes at 90 ppm results in pulmonary oedema. But the most significant aspect of nitrogen dioxide pollution is its role in the initiation of photochemical reactions in presence of hydrocarbons leading to the production of secondary pollutants. In this paper, determination and control of nitrogen dioxide has been discussed. In one method of low concentration determination less than 5 ppm, the air sample is drawn by sampling probe and is pumped through rotameter which force the air with high pressure into the impinger containing the absorbing reagent. In another method of high concentration determination more than 5 ppm, the reagent is kept in glass syringe which sucks the air sample into it and then shaken vigorously to allow the absorption of NO2 completely resulting in change in color of absorbed sample. Several methods and technologies have been devised to control the emission of NO2. These methods include two-stage combustion, flue gas recirculation, burner design modifications, effluent gas treatment, TYCO process, adsorption on solids, catalytic decomposition etc. by which NO2 formation can be curbed. Gaurav Kumar Singh & Kunal Gupta 282