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Urban NO2 and NO pollution in relation to the North Atlantic Oscillation NAO

Grundström, Maria; Linderholm, Hans; Klingberg, Jenny and Pleijel, Håkan LU (2011) In Atmospheric Environment 45(4). p.883-888
Abstract
The North Atlantic Oscillation (NAO), a measure of the strength of the zonal wind across the North Atlantic Ocean, strongly influences weather conditions in NW Europe, e.g. temperature, precipitation and wind, especially during winter. It was hypothesised that elevated concentrations of nitrogen oxides in Gothenburg would be enhanced during negative NAO index (NAOI) conditions, representing more anticyclonic weather situations and thus leading to limited air mixing in the urban atmosphere, than situations with NAOI> 0. Hourly wintertime (December-February) concentrations (1997-2006) of NO2, NO, air pressure, temperature and wind direction from an urban rooftop (30 m above street level) in the centre of the City of Gothenburg were... (More)
The North Atlantic Oscillation (NAO), a measure of the strength of the zonal wind across the North Atlantic Ocean, strongly influences weather conditions in NW Europe, e.g. temperature, precipitation and wind, especially during winter. It was hypothesised that elevated concentrations of nitrogen oxides in Gothenburg would be enhanced during negative NAO index (NAOI) conditions, representing more anticyclonic weather situations and thus leading to limited air mixing in the urban atmosphere, than situations with NAOI> 0. Hourly wintertime (December-February) concentrations (1997-2006) of NO2, NO, air pressure, temperature and wind direction from an urban rooftop (30 m above street level) in the centre of the City of Gothenburg were analysed in relation to NAOI. Air pressure, the average concentration of nitrogen oxides (NOx = NO2 + NO), as well as the fraction of hourly NO2 and NO concentrations exceeding 90 mu g m(-3) and the fraction of daily NO concentrations exceeding 60 mu g m(-3), were significantly and negatively related to NAOI. Air temperature was positively correlated with NAOI. Southerly and westerly winds were more common in months with positive NAOI, while easterly and northerly winds were overrepresented in months with negative NAOI. High pollution concentrations dominantly occurred in situations with northerly and easterly wind directions. High NO2 and NO concentrations were associated with negative NAOI, especially in the morning when the traffic rush coincided with restricted air mixing. Over the ten-year period there were trends for more negative NAOI and increased time fractions with hourly NO2 concentrations exceeding 90 mu g m(-3). The conclusion of this study is that a climate shift towards higher or lower NAOI has the potential to significantly influence urban air pollution in North-West Europe, and thus the possibility to reach air quality standards, even if emissions remain constant. (C) 2010 Elsevier Ltd. All rights reserved. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
North Atlantic Oscillation, NO2, NOx, Urban pollution, Climate, Gothenburg
in
Atmospheric Environment
volume
45
issue
4
pages
883 - 888
publisher
Elsevier
external identifiers
  • scopus:78650976891
ISSN
1352-2310
DOI
10.1016/j.atmosenv.2010.11.023
project
BECC
language
English
LU publication?
no
id
72881691-b134-45d6-9c31-422a2bcbc3b5 (old id 4448690)
date added to LUP
2014-05-23 12:11:26
date last changed
2017-09-24 04:14:06
@article{72881691-b134-45d6-9c31-422a2bcbc3b5,
  abstract     = {The North Atlantic Oscillation (NAO), a measure of the strength of the zonal wind across the North Atlantic Ocean, strongly influences weather conditions in NW Europe, e.g. temperature, precipitation and wind, especially during winter. It was hypothesised that elevated concentrations of nitrogen oxides in Gothenburg would be enhanced during negative NAO index (NAOI) conditions, representing more anticyclonic weather situations and thus leading to limited air mixing in the urban atmosphere, than situations with NAOI> 0. Hourly wintertime (December-February) concentrations (1997-2006) of NO2, NO, air pressure, temperature and wind direction from an urban rooftop (30 m above street level) in the centre of the City of Gothenburg were analysed in relation to NAOI. Air pressure, the average concentration of nitrogen oxides (NOx = NO2 + NO), as well as the fraction of hourly NO2 and NO concentrations exceeding 90 mu g m(-3) and the fraction of daily NO concentrations exceeding 60 mu g m(-3), were significantly and negatively related to NAOI. Air temperature was positively correlated with NAOI. Southerly and westerly winds were more common in months with positive NAOI, while easterly and northerly winds were overrepresented in months with negative NAOI. High pollution concentrations dominantly occurred in situations with northerly and easterly wind directions. High NO2 and NO concentrations were associated with negative NAOI, especially in the morning when the traffic rush coincided with restricted air mixing. Over the ten-year period there were trends for more negative NAOI and increased time fractions with hourly NO2 concentrations exceeding 90 mu g m(-3). The conclusion of this study is that a climate shift towards higher or lower NAOI has the potential to significantly influence urban air pollution in North-West Europe, and thus the possibility to reach air quality standards, even if emissions remain constant. (C) 2010 Elsevier Ltd. All rights reserved.},
  author       = {Grundström, Maria and Linderholm, Hans and Klingberg, Jenny and Pleijel, Håkan},
  issn         = {1352-2310},
  keyword      = {North Atlantic Oscillation,NO2,NOx,Urban pollution,Climate,Gothenburg},
  language     = {eng},
  number       = {4},
  pages        = {883--888},
  publisher    = {Elsevier},
  series       = {Atmospheric Environment},
  title        = {Urban NO2 and NO pollution in relation to the North Atlantic Oscillation NAO},
  url          = {http://dx.doi.org/10.1016/j.atmosenv.2010.11.023},
  volume       = {45},
  year         = {2011},
}