%0 Journal Article
%A Zhao, Defeng
%A Schmitt, Sebastian H.
%A Wang, Mingjin
%A Acir, Ismail-Hakki
%A Tillmann, Ralf
%A Tan, Zhaofeng
%A Novelli, Anna
%A Fuchs, Hendrik
%A Pullinen, Iida
%A Wegener, Robert
%A Rohrer, Franz
%A Wildt, Jürgen
%A Kiendler-Scharr, Astrid
%A Wahner, Andreas
%A Mentel, Thomas F.
%T Effects of NO$_{x}$ and SO$_{2}$ on the secondary organic aerosol formation from photooxidation of <i>α</i>-pinene and limonene
%J Atmospheric chemistry and physics
%V 18
%N 3
%@ 1680-7324
%C Katlenburg-Lindau
%I EGU
%M FZJ-2018-02214
%P 1611 - 1628
%D 2018
%X Anthropogenic emissions such as NOxand SO2influence the biogenic secondary organic aerosol (SOA) for-mation, but detailed mechanisms and effects are still elusive.We  studied  the  effects  of  NOxand  SO2on  the  SOA  for-mation from the photooxidation ofα-pinene and limoneneat  ambient  relevant  NOxand  SO2concentrations  (NOx:< 1to 20 ppb, SO2: < 0.05 to 15 ppb). In these experiments,monoterpene oxidation was dominated by OH oxidation. Wefound that SO2induced nucleation and enhanced SOA massformation.  NOxstrongly  suppressed  not  only  new  particleformation but also SOA mass yield. However, in the presenceof SO2which induced a high number concentration of parti-cles after oxidation to H2SO4, the suppression of the massyield  of  SOA  by  NOxwas  completely  or  partly  compen-sated for. This indicates that the suppression of SOA yieldby NOxwas largely due to the suppressed new particle for-mation, leading to a lack of particle surface for the organ-ics to condense on and thus a significant influence of vaporwall loss on SOA mass yield. By compensating for the sup-pressing effect on nucleation of NOx, SO2also compensatedfor the suppressing effect on SOA yield. Aerosol mass spec-trometer data show that increasing NOxenhanced nitrate for-mation. The majority of the nitrate was organic nitrate (57–77 %), even in low-NOxconditions (<∼1 ppb). Organic ni-trate contributed 7–26 % of total organics assuming a molec-ular weight of 200 g mol−1. SOA fromα-pinene photooxida-tion at high NOxhad a generally lower hydrogen to carbonratio (H/C), compared to low NOx. The NOxdependenceof the chemical composition can be attributed to the NOxde-pendence of the branching ratio of the RO2loss reactions,leading  to  a  lower  fraction  of  organic  hydroperoxides  andhigher fractions of organic nitrates at high NOx. While NOxsuppressed new particle formation and SOA mass formation,SO2can compensate for such effects, and the combining ef-fect of SO2and NOxmay have an important influence onSOA formation affected by interactions of biogenic volatileorganic compounds (VOCs) with anthropogenic emissions
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000424122600003
%R 10.5194/acp-18-1611-2018
%U https://juser.fz-juelich.de/record/844863