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<p class="MsoNormal"><span style="font-size:11.0pt">Jibin Dou, Tengyu Liu, Dafeng Ge, Ying Zhang, Junchao Yin, Lei Wang, Haoyu Liu, Duzitian Li, Guangdong Niu, Liangduo Chen, Jiaping Wang, Ximeng Qi, Wei Nie, Xuguang Chi, Xin Huang, Aijun Ding, In-situ secondary
organic aerosol formation from ambient air in suburban Eastern China: Substantially distinct characteristics between summer and winter, Atmospheric Environment, <a href="https://doi.org/10.1016/j.atmosenv.2025.121295" target="_blank">https://doi.org/10.1016/j.atmosenv.2025.121295</a>,
356, 121295, 2025.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt">Abstract</span></b><span style="font-size:11.0pt">. Elucidating the sources and formation mechanisms of secondary organic aerosol (SOA) is essential to access its impact on air quality and climate, yet
the seasonal variations of SOA formation from ambient air remain poorly constrained. In this study, in-situ SOA formation from ambient air at a suburban site in Nanjing in the Yangtze River Delta of eastern China during summer and winter was investigated using
an oxidation flow reactor (OFR), with equivalent photochemical age in the OFR ranging from several hours to 3 weeks. Substantially distinct SOA mass enhancements and precursor characteristics were observed during these two seasons. In summer, the average OH
exposure-dependent OA enhancements were </span><span style="font-size:11.0pt;font-family:"Cambria Math",serif">∼</span><span style="font-size:11.0pt">0.77</span><span style="font-size:11.0pt">–</span><span style="font-size:11.0pt">2.64</span><span style="font-size:11.0pt"> μ</span><span style="font-size:11.0pt">g</span><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt">m</span><span style="font-size:11.0pt">−</span><span style="font-size:11.0pt">3,
much higher than </span><span style="font-size:11.0pt;font-family:"Cambria Math",serif">∼</span><span style="font-size:11.0pt">0.24</span><span style="font-size:11.0pt"> μ</span><span style="font-size:11.0pt">g</span><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt">m</span><span style="font-size:11.0pt">−</span><span style="font-size:11.0pt">3
in winter. The known SOA precursors contributed approximately 31</span><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt">% and 18</span><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt">% of the measured SOA during summer
daytime and nighttime and 25</span><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt">% and 89</span><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt">% during winter daytime and nighttime, respectively. In summer, biogenic
volatile organic compounds (BVOCs) contributed to approximately 56 % of the estimated SOA during the daytime while aromatics accounted for 76 % at night. By contrast, C6-C9 aromatics were the dominant SOA precursors during the daytime and nighttime in winter.
The unexplained SOA may be attributed to the unmeasured semi-volatile and intermediate volatile organic compounds (S/IVOCs) and precursors emitted from volatile chemical products (VCPs). This study highlights the significant seasonal differences in SOA formation
potential in suburban eastern China.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><a href="https://sites.google.com/site/pamwiki/publications-using-the-pam-oxidation-flow-reactor?authuser=0">PAM Wiki - Publications Using the PAM Oxidation Flow Reactor</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-ligatures:none">Andrew Lambe<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-ligatures:none">Principal Scientist<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-ligatures:none">Aerodyne Research, Inc.
<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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