This study analyzed the characteristics of air pollution and specific pollution periods within the Harbin-Changchun (HC) metropolitan area during 2014–2020. Regarding annual, seasonal, and monthly variations of the six pollutants, the change trend in 11 cities of HC showed strong consistency in spatial distribution. The western cities (Songyuan, Daqing, and Siping) were vulnerable to dust storms from Inner Mongolia. The concentrations of all air pollutants, except O3-8h, showed downward fluctuation trends from 2014 to 2018 and remained stable from 2018 to 2020 in terms of annual variations. The inter-annual trend of significant reductions in SO2 and SO2/PM2.5 during the heating period indicated that strict emission reduction measures posed by the government were highly successful. The ratio of PM2.5/SO2 was used to identify open biomass burning (OBB), which showed a double peak (October–November (Oct–Nov), March–April (Mar–Apr)). The burning prohibition shifted the OBB from Oct–Nov to Mar–Apr. •Long-term records of air pollution were presented for Harbin-Changchun (HC) region.•PM2.5 tended to decrease whereas O3 concentrations were largely unchanged.•SO2 exhibited an apparent decreasing trend for the HC region.•Open burning activities remained evident despite strict bans on agricultural fires.•The western cities in HC were strongly impacted by dust during spring.