Black carbon (BC) is a refractory form of carbonaceous aerosol generated from fossil fuel and biomass incomplete combustion, which has adverse influence on global warming, air pollution, and human health. However, the relative importance of different sources and meteorology on atmospheric BC evolution was not well understood yet, especially during special periods when series of rigorous emission reduction measures were employed. Here, over one-year observation of BC concentration was conducted in urban of Hangzhou, China from Dec. 2022 to Jan. 2024. The annual mean BC concentration was 1.99±1.25 μg/m