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Time span and spatial scale of regional new particle formation events over Finland and Southern Sweden

Hussein, T.; Junninen, H.; Tunved, P.; Kristensson, Adam LU ; Dal Maso, M.; Riipinen, I.; Aalto, P. P.; Hansson, H. -C.; Swietlicki, E. and Kulmala, M. (2009) In Atmospheric Chemistry and Physics 9(14). p.4699-4716
Abstract
We investigated the time span and spatial scale of regional new particle formation (NPF) events in Finland and Southern Sweden using measured particle number size distributions at five background stations. We define the time span of a NPF event as the time period from the first moment when the newly formed mode of aerosol particles is observable below 25 nm until the newly formed mode is not any more distinguishable from other background modes of aerosol particles after growing to bigger sizes. We identify the spatial scale of regional NPF events based on two independent approaches. The first approach is based on the observation within a network of stationary measurement stations and the second approach is based on the time span and the... (More)
We investigated the time span and spatial scale of regional new particle formation (NPF) events in Finland and Southern Sweden using measured particle number size distributions at five background stations. We define the time span of a NPF event as the time period from the first moment when the newly formed mode of aerosol particles is observable below 25 nm until the newly formed mode is not any more distinguishable from other background modes of aerosol particles after growing to bigger sizes. We identify the spatial scale of regional NPF events based on two independent approaches. The first approach is based on the observation within a network of stationary measurement stations and the second approach is based on the time span and the history of air masses back-trajectories. According to the second approach, about 60% and 28% of the events can be traced to distances longer than 220 km upwind from where the events were observed in Southern Finland (Hyytiala) and Northern Finland (Varrio), respectively. The analysis also showed that the observed regional NPF events started over the continents but not over the Atlantic Ocean. The first approach showed that although large spatial scale NPF events are frequently observed at several locations simultaneously, they are rarely identical (similar characteristics and temporal variations) due to differences in the initial meteorological and geographical conditions between the stations. The growth of the newly formed particles during large spatial scale events can be followed for more than 30 h where the newly formed aerosol particles end up in the Aitken mode (diameter 25-100 nm) and accumulation mode size ranges (diameter 0.1-1 mu m). This study showed clear evidence that regional NPF events can pose a significant source for accumulation mode particles over the Scandinavian continent provided that these findings can be generalized to many of the air masses traveling over the European continent. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Atmospheric Chemistry and Physics
volume
9
issue
14
pages
4699 - 4716
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • wos:000268535500012
  • scopus:77951983784
ISSN
1680-7324
language
English
LU publication?
yes
id
e2c2184d-ad35-4c4a-9e54-b721fc8649f8 (old id 1460130)
date added to LUP
2009-08-25 12:22:44
date last changed
2017-11-19 03:28:15
@article{e2c2184d-ad35-4c4a-9e54-b721fc8649f8,
  abstract     = {We investigated the time span and spatial scale of regional new particle formation (NPF) events in Finland and Southern Sweden using measured particle number size distributions at five background stations. We define the time span of a NPF event as the time period from the first moment when the newly formed mode of aerosol particles is observable below 25 nm until the newly formed mode is not any more distinguishable from other background modes of aerosol particles after growing to bigger sizes. We identify the spatial scale of regional NPF events based on two independent approaches. The first approach is based on the observation within a network of stationary measurement stations and the second approach is based on the time span and the history of air masses back-trajectories. According to the second approach, about 60% and 28% of the events can be traced to distances longer than 220 km upwind from where the events were observed in Southern Finland (Hyytiala) and Northern Finland (Varrio), respectively. The analysis also showed that the observed regional NPF events started over the continents but not over the Atlantic Ocean. The first approach showed that although large spatial scale NPF events are frequently observed at several locations simultaneously, they are rarely identical (similar characteristics and temporal variations) due to differences in the initial meteorological and geographical conditions between the stations. The growth of the newly formed particles during large spatial scale events can be followed for more than 30 h where the newly formed aerosol particles end up in the Aitken mode (diameter 25-100 nm) and accumulation mode size ranges (diameter 0.1-1 mu m). This study showed clear evidence that regional NPF events can pose a significant source for accumulation mode particles over the Scandinavian continent provided that these findings can be generalized to many of the air masses traveling over the European continent.},
  author       = {Hussein, T. and Junninen, H. and Tunved, P. and Kristensson, Adam and Dal Maso, M. and Riipinen, I. and Aalto, P. P. and Hansson, H. -C. and Swietlicki, E. and Kulmala, M.},
  issn         = {1680-7324},
  language     = {eng},
  number       = {14},
  pages        = {4699--4716},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Atmospheric Chemistry and Physics},
  title        = {Time span and spatial scale of regional new particle formation events over Finland and Southern Sweden},
  volume       = {9},
  year         = {2009},
}