EGU25-17382, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-17382
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Assessment the effect of emission reductions on long-term trend in carbonaceous aerosols from 2014 to 2021 in eastern China
Chang Zhou, Wei Nie, Xuguang Chi, Caijun Zhu, and Aijun Ding
Chang Zhou et al.
  • Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China (chang.zhou@smail.nju.edu.cn)

As a key fraction of fine particulate matter (PM2.5), carbonaceous aerosol has a significant impact on climate and human health. This study investigates the long-term variations in carbonaceous aerosols from 2014 to 2021 in Nanjing, China. We observed substantial decreasing trends in organic carbon (OC) (-8.0% yr-1) and elemental carbon (EC) (-8.3% yr-1), mainly driven by reductions in primary carbonaceous components. Notably, secondary organic carbon (SOC) did not exhibit a significant decreasing trend (-2.0% yr-1), while its contribution to OC increased substantially (16.4% yr-1), indicating its growing importance in organic aerosol. Compared to changes in meteorological factors, emission reduction played a dominant role in the decrease of carbonaceous aerosols. Moreover, considering two key clean air actions and the COVID-19 pandemic, we thoroughly assessed the effect of emission reduction on different carbonaceous components throughout three phases: Phase I (2014-2017), Phase II (2017-2019), and Phase III (2019-2021). The varying trends of primary carbonaceous components over the three phases highlight their dynamic response to various emission control measures implemented over distinct phases. Given the relatively stable atmospheric oxidation and the limited decrease in volatile organic compounds (VOCs) in Phase III, the unexpected significant reduction trend observed in SOC (-12.7% yr-1) during that phase may be significantly attributed to the notably higher reduction rate in primary carbonaceous components, as secondary organic aerosol (SOA) formation can be enhanced in the presence of primary organic aerosol (POA). Our findings provide a new insight into assessing the effectiveness of emission control measures on SOC trend.

How to cite: Zhou, C., Nie, W., Chi, X., Zhu, C., and Ding, A.: Assessment the effect of emission reductions on long-term trend in carbonaceous aerosols from 2014 to 2021 in eastern China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17382, https://doi.org/10.5194/egusphere-egu25-17382, 2025.