Аннотация:The dynamics of the surface air pollution in Moscow have been discussed in details. High values of the NO/NO2 ratio and an appearance of secondary nocturnal maximum at diurnal course of ozone in warm period are specific features of the urban chemical climate. In warm period the morning maximum of NO and CO concentrations is considerably larger as a rule than the evening one. Probably, this effect is connected with frequent existence of elevated inversions in the low 300 m height air layer during morning hours.