The trend toward global warming has become more and more apparent in recent years. It has been widely accepted that CO2 is the main contributor to this process and that CO2 emissions urgently need to be reduced. However, the capital cost for CO2 capture from a coal-fired power station using traditional solvent absorption technology is relatively high. A possible solution to reduce the cost is to achieve absorption of SO2, NOx, and CO2 in a one-step process. Potassium carbonate (K2CO3) is a potential solvent for absorbing all of these components simultaneously. To apply this absorption process in an industrial situation, it is very important to understand the interaction between the solvent and minor components contained in the flue gas, such as SO2 and NOx. The effect of SO2 on CO2 absorption using K2CO3 solutions has been previously discussed. This paper studies the influence of NOx upon CO2 absorption using 30 wt % K2CO3 solvent. It was found that the reaction between NOx and K2CO3 was irreversible, which would result in the accumulation of NO2- and NO3- in the solvent using an industrial flue gas process, with a simultaneous reduction in the CO32- concentration.