The abundance of some pollutants from the air depend on the geographic area, the human activities intensity, the climate, the season and even on the hour within a day. The nitrogen oxides are the most abundant and most dangerous toxic species from the air, and these emissions are tightly connected to human polluting activities. Therefore, in our work, the first part is assigned for a wide literature search concerning the incidence of the keywords �nitrogen oxide� and searching the connections with other significant related terms and formulas, investigated by the researches worldwide. Then, a statistic approach was applied trying to correlate the values of the concentration in air of nitrogen monoxide, nitrogen dioxide, carbon monoxide, sulfur dioxide, benzene and particulate matter PM10, all of these being generated to a large extent from the exhaust gases from different automotives. The data were collected from the official site of the National Network of Air Quality Monitoring from Romania, and processed by statistical methods, using specific software and methods, in order to find significant differences between the pollutants concentrations values in two neighbor counties (Suceava and Botosani), with relatively similar climate conditions, but different social wealth. The findings of these statistical processing indicate that the PM10 values do not present significant differences between the two locations, neither the time within a day, while the other parameters exhibit distinctions between the values of the other pollutants concentrations in different seasons (summer and winter) and hourly intervals within a day (night, morning, afternoon and evening).
