The recovery of single wall nanotube (SWNT) based gas sensors have been investigated in the presence of Ultraviolet (UV) light at ambient conditions by real time monitoring. The rate of recovery is same for low concentration upto 5 ppm, but decreases with increase in concentration of NO2. It is observed that the response of thick film resistor (CNT-TFR) remains 7.5 and 25.4 % with multiple exposures of 5 ppm and 20 ppm NO2 concentration, respectively. But the recovery rate decreases with multiple exposures. Both the response and recovery rate changes in case of micro resistor (CNT-µR). To study the significant effect of absorbed O2 in recovery behavior, the analyte is exposed to gas sensor with and without regeneration in the presence of UV light. The gas sensor response increases 1.5 times but it does not recover to its base line when regenerated in the presence of UV light.