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 N2 O5 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 o...
Saved in:
Published in | Atmospheric chemistry and physics Vol. 10; no. 20; pp. 9781 - 9795 |
---|---|
Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Katlenburg-Lindau
Copernicus GmbH
01.01.2010
Copernicus Publications |
Online Access | Get full text |
Cover
Loading…
Summary: | Broadband cavity enhanced absorption spectroscopy (BBCEAS) has been used to measure the sum of concentrations of NO3 and N2 O5 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 +N2 O5 mixing ratios reached 800 pptv, whereas the mean night-time NO3 +N2 O5 was approximately 30 pptv. Additionally, [NO3 +N2 O5 ] showed negative correlations with [NO] and [NO2 ] and a positive correlation with [O3 ]. Co-measurements of temperature and NO2 from the BT Tower were used to calculate the equilibrium partitioning between NO3 and N2 O5 which was always found to strongly favour N2 O5 (NO3 /N2 O5 =0.01 to 0.04). Two methods are used to calculate the lifetimes for NO3 and N2 O5 , 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 . |
---|---|
ISSN: | 1680-7316 1680-7324 |
DOI: | 10.5194/acp-10-9781-2010 |