Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air 1Max-Planck-Institut für Chemie, Division of Atmospheric Chemistry, Mainz, Germany
03 Nov 2011
2Max-Planck-Institut für Chemie, Particle Chemistry Department, Mainz, Germany
3Institute for Atmospheric Physics, University of Mainz, Germany
4Faculty of Chemistry, University of Sciences and Technology Houari Boumediene (USTHB), Algiers, Algeria
5Institut of Environmetal Physics, University of Heidelberg, Germany
Received: 08 Jun 2011 – Published in Atmos. Chem. Phys. Discuss.: 23 Jun 2011Abstract. Nighttime mixing ratios of boundary layer N2O5 were determined
using cavity-ring-down spectroscopy during the DOMINO campaign in
Southern Spain (Diel Oxidant Mechanisms In relation to Nitrogen Oxides,
21 November 2008–8 December 2008). N2O5 mixing ratios ranged from below the
detection limit (~5 ppt) to ~500 ppt. A steady-state analysis
constrained by measured mixing ratios of N2O5, NO2 and
O3 was used to derive NO3 lifetimes and compare them to calculated
rates of loss via gas-phase and heterogeneous reactions of both NO3 and
N2O5. Three distinct types of air masses were encountered, which
were largely marine (Atlantic), continental or urban-industrial in origin.
NO3 lifetimes were longest in the Atlantic sector (up to ~30 min) but were very short (a few seconds) in polluted, air masses from the
local city and petroleum-related industrial complex of Huelva. Air from the
continental sector was an intermediate case. The high reactivity to NO3
of the urban air mass was not accounted for by gas-phase and heterogeneous
reactions, rates of which were constrained by measurements of NO, volatile
organic species and aerosol surface area. In general, high NO2 mixing
ratios were associated with low NO3 lifetimes, though heterogeneous
processes (e.g. reaction of N2O5 on aerosol) were generally less
important than direct gas-phase losses of NO3. The presence of SO2
at levels above ~2 ppb in the urban air sector was always associated
with very low N2O5 mixing ratios indicating either very short
NO3 lifetimes in the presence of combustion-related emissions or an
important role for reduced sulphur species in urban, nighttime chemistry.
High production rates coupled with low lifetimes of NO3 imply an
important contribution of nighttime chemistry to removal of both NOx and VOC.
Revised: 22 Sep 2011 – Accepted: 04 Oct 2011 – Published: 03 Nov 2011
Citation: Crowley, J. N., Thieser, J., Tang, M. J., Schuster, G., Bozem, H., Beygi, Z. H., Fischer, H., Diesch, J.-M., Drewnick, F., Borrmann, S., Song, W., Yassaa, N., Williams, J., Pöhler, D., Platt, U., and Lelieveld, J.: Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air, Atmos. Chem. Phys., 11, 10853-10870, doi:10.5194/acp-11-10853-2011, 2011.