Multiday production of condensing organic aerosol mass in urban and forest outflow

摘要: Abstract. Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases SOA mass continuing for multiple days urban outflow, even as initial parcel diluted into regional atmosphere. The increase forest outflow more modest (~50%) and of shorter duration (1–2 days). multiday stems from oxidation precursors which persist equilibrium with particle phase, can be attributed to multigenerational reaction products both aromatics alkanes, especially those relatively low carbon numbers (C4–15). In particular we find large contributions substituted maleic anhydrides multi-substituted peroxide-bicyclic alkenes. results that predicted a robust feature our model under changing atmospheric conditions different vapor pressure schemes, contradict notion undergoes little beyond short formation period. imply could influence radiative characteristics atmosphere over an extremely wide region, measurements near precursor sources may routinely underestimate this influence.