<p>Carbonaceous aerosols adversely affect air quality, visibility and public health. Understanding their regional variations and sources in China is essential for improving air quality control. Carbonaceous aerosols were collected during winter in four major Chinese cities—Xi’an (XA), Shijiazhuang (SJZ), Wuhan (WH), and Chongqing (CQ)—to investigate their pollution characteristics. A comprehensive analysis of various carbon fractions was conducted, including organic carbon (OC), elemental carbon (EC), and specific subfractions such as OC1 – OC4, EC1 – EC3, char-EC, and soot-EC. Using the hybrid environmental receptor model (HERM), we identified emission sources and quantified their contributions to total carbon (TC) in these urban areas. The findings demonstrate substantial impacts from biomass burning and coal combustion during the heating season in XA. Vehicular emissions account for a considerable proportion, particularly in SJZ, corresponding with the increase in automobile ownership in that city. In WH and CQ, emissions from industrial and residential coal utilization, especially from the steel industry, are markedly higher. Additionally, the COVID-19 pandemic results in reduced contributions from industrial emissions in WH and SJZ. We further investigate the optical characteristics of EC, revealing that the average mass absorption efficiency (MAE) values across the four cities are consistent with previous studies. The light absorption coefficient of EC originating from different emission sources demonstrates a higher contribution from biomass burning, coal combustion and stationary combustion in XA, WH and CQ, respectively. In contrast, vehicle emissions exhibit higher contributions in SJZ. This study delineates the distinct characteristics of carbonaceous aerosols in northern and southern Chinese cities, providing a robust scientific basis for urban air pollution mitigation strategies.</p>