Abstract: On the basis of analysis of the production, movement and transforming laws of urban automobile tailing pollutants (NO_x), the mathematical model of urban automobile tailing gas pollutants (NO_x) were presented and applied, to simulate and predict the automobile pollutants(NO_x) concentration on the road with many automobile passing through. The comparison between the monitored data and the calculated results proves that the absolute value of average bias was less than 0.02 mg/m³, the value of relative bias was less than 0.32, which shows that the mathematical model of urban automobile tailing pollutants (NO_x) concentration well reflects the actual situation.

Key words: automobile tailing gas, pollutant NO_x, mathematical model