TY - JOUR A1 - Crowley, John Nicholas A1 - Schuster, Gerhard A1 - Pouvesle, Nicolas A1 - Parchatka, Uwe A1 - Fischer, Horst A1 - Bonn, Boris A1 - Bingemer, Heinz A1 - Lelieveld, Johannes T1 - Nocturnal nitrogen oxides at a rural mountain-site in south-western Germany T2 - Atmospheric chemistry and physics, 10.2010, S. 2795-2812 N2 - A new, two-channel instrument for simultaneous NO3 and N2O5 monitoring was used to make the first comprehensive set of nocturnal NOx measurements (NO, NO2, NO3 and N2O5) at the Taunus Observatory, a rural mountain site (Kleiner Feldberg) in South-western Germany. In May 2008, NO3 and N2O5 mixing ratios were well above the instrumental detection limit (a few ppt) on all nights of the campaign and were characterised by large variability. The concentrations of NO3, N2O5 and NO2 were consistent with the equilibrium constant, K2, defining the rates of formation and thermal dissociation of N2O5. A steady-state lifetime analysis is consistent with the loss of nocturnal NOx being dominated by the reaction of NO3 with volatile organic compounds in this forested region, with N2O5 uptake to aerosols of secondary importance. Analysis of a limited dataset obtained at high relative humidity indicated that the loss of N2O5 by reaction with water vapour is less efficient (>factor 3) than derived using laboratory kinetic data. The fraction of NOx present as NO3 and N2O5 reached ~20% on some nights, with night-time losses of NOx competing with daytime losses. Y1 - 2010 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/7839 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30-77981 SN - 1680-7316 SN - 1680-7324 N1 - © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. VL - 10 SP - 2795 EP - 2812 PB - European Geosciences Union CY - Katlenburg-Lindau ER -