Abstract: According to the ground-based multi axis differential absorption spectrometer (max-DOAS), from January 2017 to December 2018 the atmospheric NO₂ and SO₂ pollution status of valley type cities on the northern slope of Tianshan Mountains were analyzed in combination with meteorology, factory, vehicle flow and other factors. The results show that the vertical column concentration of NO₂ VCD was higher than SO₂ VCD in the northern slope of Tianshan Mountains at the same time, showing the characteristics of low at noon and high in the morning and evening, and from large to small in winter, spring, autumn and summer. Spatially, NO₂ VCD of factories, traffic arteries and atmospheric NO₂ VCD near Tianshan Mountains were higher in valley cities on the northern slope of Tianshan Mountains. The valley city on the northern slope of Tianshan Mountains is located at the bottom of the valley, which is easy to produce inversion layer and make the air pollutants difficult to diffuse. The characteristics of urban layout make the air pollution in Fukang and Wusu be aggravated, while that of Bole be reduced. Moreover, the air pollutants carried by foreign air masses will aggravate the atmospheric NO₂ and SO₂ pollution of valley cities on the northern slope of Tianshan Mountains. The pollution degree of NO₂ and SO₂ in the urban air was different with different industrial types. The pollution degree of the city from heavy to light is the secondary industry > the tertiary industry > the primary industry.

Key words: the northern slope of Tianshan Mountains, valley city, vertical column concentration of NO₂, vertical column concentration of SO₂