Night-time chemistry above London: Measurements of NO3 and N2O5 from the BT Tower

Broadband cavity enhanced absorption spectroscopy (BBCEAS) has been used to measure the sum of concentrations of NO3 and N2O 5 from the BT (telecommunications) Tower 160 m above street level in central London during the REPARTEE II campaign in October and November 2007. Substantial variability was observed in these night-time nitrogen compounds: peak NO3+N2O5 mixing ratios reached 800 pptv, whereas the mean night-time NO3+N2O5 was approximately 30 pptv. Additionally, [NO3+N2O5] showed negative correlations with [NO] and [NO2] and a positive correlation with [O3]. Co-measurements of temperature and NO 2 from the BT Tower were used to calculate the equilibrium partitioning between NO3 and N2O5 which was always found to strongly favour N2O5 (NO 3/N2O5Combining double low line0.01 to 0.04). Two methods are used to calculate the lifetimes for NO3 and N 2O5, the results being compared and discussed in terms of the implications for the night-time oxidation of nitrogen oxides and the night-time sinks for NOy. © 2010 Author(s).

Bibliographic Details

Main Authors:	Benton, A.K., Langridge, J.M., Ball, S.M., Bloss, W.J., Dall'Osto, Manuel, Nemitz, E., Harrison, Roy M., Jones, R.L.
Format:	artículo biblioteca
Published:	European Geophysical Society 2010
Online Access:	http://hdl.handle.net/10261/217568
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