Considering the air pollution actual issues, in special for the industrial cities, in the present paper were established some correlations between NOx concentration and some climatic factors. The data were obtained from Bacau air quality monitoring stations and are related to 2011. The climatic factors analyzed were air temperature, atmospheric pressure, atmospheric humidity, solar radiation, wind speed and direction. The data interpretations reveal some direct influence of the air NOx concentration dispersion and analyzed climatic factors variation.