Preprints
https://doi.org/10.5194/acp-2021-982
https://doi.org/10.5194/acp-2021-982
 
11 Jan 2022
11 Jan 2022
Status: a revised version of this preprint was accepted for the journal ACP and is expected to appear here in due course.

Eddy Covariance Measurements Highlight Sources of Nitrogen Oxide Emissions Missing from Inventories for Central London

Will S. Drysdale1, Adam R. Vaughan1, Freya A. Squires1,a, Sam J. Cliff1, Stefan Metzger2,3, David Durden2, Natchaya Pingintha-Durden2, Carole Helfter4, Eiko Nemitz4, C. Sue B. Grimmond5, Janet Barlow5, Sean Beevers7, Gregor Stewart7, David Dajnak7, Ruth M. Purvis1,6, and James D. Lee1,6 Will S. Drysdale et al.
  • 1Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, UK
  • 2Battelle, National Ecological Observatory Network. 1685 38th Street, Boulder, CO 80301, USA
  • 3Dept of Atmospheric and Oceanic Sciences, University ofWisconsin-Madison, 1225 W Dayton St, Madison, WI 53711 USA
  • 4UK Centre for Ecology and Hydrology, Bush Estate, Penicuik, EH26 0QB, UK
  • 5Department of Meteorology, University of Reading, Reading, RG6 6BB, UK
  • 6National Centre for Atmospheric Science, University of York, York, UK
  • 7MRC Centre for Environment and Health, Imperial College London, London, UK
  • anow at: British Antarctic Survey, Natural Environment Research Council, Cambridge, CB3 0ET, UK

Abstract. During March–June 2017 emissions of nitrogen oxides were measured via eddy covariance at the British Telecom Tower in central London, UK. Through the use of a footprint model the expected emissions were simulated from the spatially resolved National Atmospheric Emissions Inventory for 2017, and compared with the measured emissions. These simulated emissions were shown to underestimate measured emissions during the day time by a factor of 1.48, but they agreed well overnight. Furthermore, underestimations were spatially mapped and the areas around the measurement site responsible for differences in measured and simulated emissions inferred. It was observed that areas of higher traffic, such as major roads near national rail stations, showed the greatest underestimation by the simulated emissions. These discrepancies are partially attributed to a combination of the inventory not fully capturing traffic conditions in central London, and both spatial and temporal resolution of the inventory not fully describing the high heterogeneity of the urban centre. Understanding of this underestimation may further improved with longer measurement time series ,to better understand temporal variation, and improved temporal scaling factors, to better simulate sub-annual emissions.

Will S. Drysdale et al.

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2021-982', Anonymous Referee #1, 31 Jan 2022
  • RC2: 'Comment on acp-2021-982', Anonymous Referee #2, 31 Jan 2022
  • AC1: 'Comment on acp-2021-982', Will Drysdale, 16 Apr 2022

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2021-982', Anonymous Referee #1, 31 Jan 2022
  • RC2: 'Comment on acp-2021-982', Anonymous Referee #2, 31 Jan 2022
  • AC1: 'Comment on acp-2021-982', Will Drysdale, 16 Apr 2022

Will S. Drysdale et al.

Will S. Drysdale et al.

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Short summary
Measurements of nitrogen oxide and nitrogen dioxide (NOx) emissions are important for a good understanding of air quality. While there are many direct measurements of NOx concentration, there are very few measurements of its emission. Measurements of emissions provide constraints to emissions inventories and air quality models. This article presents measurements of NOx emission from the BT Tower in central London in 2017, and compares them with inventories, finding they underestimate by ~1.48 x.
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