Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air
Item
Title (Dublin Core)
Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air
Description (Dublin Core)
Nighttime mixing ratios of boundary layer N<sub>2</sub>O<sub>5</sub> 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). N<sub>2</sub>O<sub>5</sub> mixing ratios ranged from below the detection limit (~5 ppt) to ~500 ppt. A steady-state analysis constrained by measured mixing ratios of N<sub>2</sub>O<sub>5</sub>, NO<sub>2</sub> and O<sub>3</sub> was used to derive NO<sub>3</sub> lifetimes and compare them to calculated rates of loss via gas-phase and heterogeneous reactions of both NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub>. Three distinct types of air masses were encountered, which were largely marine (Atlantic), continental or urban-industrial in origin. NO<sub>3</sub> 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 NO<sub>3</sub> 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 NO<sub>2</sub> mixing ratios were associated with low NO<sub>3</sub> lifetimes, though heterogeneous processes (e.g. reaction of N<sub>2</sub>O<sub>5</sub> on aerosol) were generally less important than direct gas-phase losses of NO<sub>3</sub>. The presence of SO<sub>2</sub> at levels above ~2 ppb in the urban air sector was always associated with very low N<sub>2</sub>O<sub>5</sub> mixing ratios indicating either very short NO<sub>3</sub> 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 NO<sub>3</sub> imply an important contribution of nighttime chemistry to removal of both NO<sub>x</sub> and VOC.
Creator (Dublin Core)
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.
Lelieveld, J.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-11-10853-2011
https://acp.copernicus.org/articles/11/10853/2011/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
