REMOVING METHOD OF NITROGEN DIOXIDE

摘要

PURPOSE: To remove NO2 conveniently and at low cost by passing a gas to be treated containing relatively low concn. NO and NO2 through a layer filled with a nitrogen dioxide adsorbent and/or a reducing agent. CONSTITUTION: The gas to be treated such as ventilated gas from an automobile tunnel or closed automobile stall containing both nitrogen monoxide and nitrogen dioxide and having <=6ppm total concn. of these is treated. This gas is passed through the layer filled with the nitrogen dioxide adsorbent such as carbonaceous adsorbent and/or reducing agent. The nitrogen dioxide in the gas is removed by adsorption and/or reduction. In this way, the NO2 harmful essentially is removed and its concn. is lowered to less than an environmental reference value of NO2 concn. by a convenient device and at low cost.