Characteristics of temporal variations in organic and elemental carbon aerosols from Eastern China in 2011-2020

We conducted a comprehensive analysis of seasonal and long-term variations in organic carbon (OC), elemental carbon (EC), primary organic carbon (POC), and secondary organic carbon (SOC) among total suspended particles on Huaniao Island, China, from 2011 to 2020. The highest OC and EC concentrations were observed in 2014 (OC, 4.13 µg/m³) and 2013 (EC, 1.21 µg/m³), respectively; for both, the lowest concentrations occurred in 2017 (OC, 1.56 µg/m³; EC, 0.69 µg/m³). OC and EC exhibited seasonal variations, such that the highest and lowest values for both occurred in winter and summer, respectively; particularly high concentrations were observed in the winter of 2014 on Huaniao Island. By 2020, winter OC and EC concentrations had decreased by 43 % and 36 %, whereas autumn OC and EC concentrations increased by 38 % and 160 % compared with 2014. In terms of carbon components, the proportions of OC4 and EC1 significantly declined, whereas the proportions of OC3 and OC2 increased, during the study period. Higher POC and SOC concentrations were mainly observed during the autumn-winter and winter-spring transition periods. POC was most strongly correlated with OC2, followed by OC4 and EC1. SOC was strongly correlated with OC3, especially in winter. These findings highlight the characteristics of temporal variations in individual carbon components, as well as possible associations with POC and SOC.