TY - JOUR AU - Zhang, Chenqi AU - Guo, Yindong AU - Shen, Hongru AU - Luo, Hao AU - Pullinen, Iida AU - Schmitt, Sebastian H. AU - Wang, Mingjin AU - Fuchs, Hendrik AU - Kiendler-Scharr, Astrid AU - Wahner, Andreas AU - Mentel, Thomas F. AU - Zhao, Defeng TI - Contrasting Influence of Nitrogen Oxides on the Cloud Condensation Nuclei Activity of Monoterpene‐Derived Secondary Organic Aerosol in Daytime and Nighttime Oxidation JO - Geophysical research letters VL - 50 IS - 4 SN - 0094-8276 CY - Hoboken, NJ PB - Wiley M1 - FZJ-2023-01934 SP - e2022GL102110 PY - 2023 AB - Anthropogenic nitrogen oxides may influence the cloud condensation nuclei (CCN) activity of biogenic secondary organic aerosols (SOA) in both daytime photooxidation and nighttime NO3 oxidation, which has significant implications for the climatic impact of SOA. We investigated the influence of NOx on the CCN activity of monoterpene-derived SOA in OH oxidation and in NO3 oxidation. In OH oxidation, NOx had little influence on the hygroscopic parameter κ of organic aerosol (κOrg), which was attributed to the minor fraction of organic nitrates (ON) in SOA (<24%), resulted from the low branching ratio of RO2 + NO to form ON. In contrast, in NO3 oxidation κOrg was much reduced compared to OH/O3 oxidation due to a dominant fraction of ON. We report κ of MT-derived ON formed in photo-oxidation and NO3 oxidation (0.029–0.052) for the first time to our knowledge, which may be used to improve model simulations of CCN concentrations. LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000949585700001 DO - DOI:10.1029/2022GL102110 UR - https://juser.fz-juelich.de/record/1006995 ER -