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Particle size distribution and particle mass measurements at urban, near-city and rural level in the Copenhagen area and Southern Sweden

Ketzel, M; Wahlin, P; Kristensson, Adam LU ; Swietlicki, Erik LU ; Berkowicz, R; Nielsen, OJ and Palmgren, F (2004) In Atmospheric Chemistry and Physics 4. p.281-292
Abstract
Particle size distribution (size-range 3-900 nm) and PM10 was measured simultaneously at an urban background station in Copenhagen, a near-city background and a rural location during a period in September-November 2002. The study investigates the contribution from urban versus regional sources of particle number and mass concentration. The total particle number (ToN) and NOx are well correlated at the urban and near-city level and show a distinct diurnal variation, indicating the common traffic source. The average ToN at the three stations differs by a factor of 3. The observed concentrations are 2500# cm(-3), 4500# cm(-3) and 7700# cm(-3) at rural, near-city and urban level, respectively. PM10 and total particle volume (ToV) are well... (More)
Particle size distribution (size-range 3-900 nm) and PM10 was measured simultaneously at an urban background station in Copenhagen, a near-city background and a rural location during a period in September-November 2002. The study investigates the contribution from urban versus regional sources of particle number and mass concentration. The total particle number (ToN) and NOx are well correlated at the urban and near-city level and show a distinct diurnal variation, indicating the common traffic source. The average ToN at the three stations differs by a factor of 3. The observed concentrations are 2500# cm(-3), 4500# cm(-3) and 7700# cm(-3) at rural, near-city and urban level, respectively. PM10 and total particle volume (ToV) are well correlated between the three different stations and show similar concentration levels, in average within 30% relative difference, indicating a common source from long-range transport that dominates the concentrations at all locations. Measures to reduce the local urban emissions of NOx and ToN are likely to affect both the street level and urban background concentrations, while for PM10 and ToV only measurable effects at the street level are probable. Taking into account the supposed stronger health effects of ultrafine particles reduction measures should address particle number emissions. The traffic source contributes strongest in the 10-200 nm particle size range. The maximum of the size distribution shifts from about 20-30 nm at kerbside to 50-60 nm at rural level. Particle formation events were observed in the 3-20 nm size range at rural location in the afternoon hours, mainly under conditions with low concentrations of preexisting aerosol particles. The maximum in the size distribution of the "traffic contribution" seems to be shifted to about 28 nm in the urban location compared to 22 nm at kerbside. Assuming NOx as an inert tracer on urban scale allows to estimate that ToN at urban level is reduced by 15-30% compared to kerbside. Particle removal processes, e. g. deposition and coagulation, which are most efficient for smallest particle sizes (<20 nm) and condensational growth are likely mechanisms for the loss of particle number and the shift in particle size. (Less)
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organization
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Contribution to journal
publication status
published
subject
in
Atmospheric Chemistry and Physics
volume
4
pages
281 - 292
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • wos:000188953200001
  • scopus:4043069140
ISSN
1680-7324
language
English
LU publication?
yes
id
7ba488ea-250b-45de-be38-edd7ffaa46fc (old id 287419)
alternative location
http://www.atmos-chem-phys.net/4/281/2004/
date added to LUP
2007-10-23 18:22:20
date last changed
2017-10-01 03:48:31
@article{7ba488ea-250b-45de-be38-edd7ffaa46fc,
  abstract     = {Particle size distribution (size-range 3-900 nm) and PM10 was measured simultaneously at an urban background station in Copenhagen, a near-city background and a rural location during a period in September-November 2002. The study investigates the contribution from urban versus regional sources of particle number and mass concentration. The total particle number (ToN) and NOx are well correlated at the urban and near-city level and show a distinct diurnal variation, indicating the common traffic source. The average ToN at the three stations differs by a factor of 3. The observed concentrations are 2500# cm(-3), 4500# cm(-3) and 7700# cm(-3) at rural, near-city and urban level, respectively. PM10 and total particle volume (ToV) are well correlated between the three different stations and show similar concentration levels, in average within 30% relative difference, indicating a common source from long-range transport that dominates the concentrations at all locations. Measures to reduce the local urban emissions of NOx and ToN are likely to affect both the street level and urban background concentrations, while for PM10 and ToV only measurable effects at the street level are probable. Taking into account the supposed stronger health effects of ultrafine particles reduction measures should address particle number emissions. The traffic source contributes strongest in the 10-200 nm particle size range. The maximum of the size distribution shifts from about 20-30 nm at kerbside to 50-60 nm at rural level. Particle formation events were observed in the 3-20 nm size range at rural location in the afternoon hours, mainly under conditions with low concentrations of preexisting aerosol particles. The maximum in the size distribution of the "traffic contribution" seems to be shifted to about 28 nm in the urban location compared to 22 nm at kerbside. Assuming NOx as an inert tracer on urban scale allows to estimate that ToN at urban level is reduced by 15-30% compared to kerbside. Particle removal processes, e. g. deposition and coagulation, which are most efficient for smallest particle sizes (&lt;20 nm) and condensational growth are likely mechanisms for the loss of particle number and the shift in particle size.},
  author       = {Ketzel, M and Wahlin, P and Kristensson, Adam and Swietlicki, Erik and Berkowicz, R and Nielsen, OJ and Palmgren, F},
  issn         = {1680-7324},
  language     = {eng},
  pages        = {281--292},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Atmospheric Chemistry and Physics},
  title        = {Particle size distribution and particle mass measurements at urban, near-city and rural level in the Copenhagen area and Southern Sweden},
  volume       = {4},
  year         = {2004},
}