Analysis of particle size distribution changes between three measurement sites in northern Scandinavia

Abstract

Abstract. We investigated atmospheric aerosol particle dynamics in a boreal forest zone in northern Scandinavia. We used aerosol number size distribution data measured with either a differential mobility particle sizer (DMPS) or scanning mobility particle sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYS-PLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of aerosol particle number size distributions during the air mass transport from the ocean to individual stations with different overland transport times, and analysis of changes in aerosol particle number size distributions during the air mass transport from one measurement station to another. Aitkenmode particles were found to have apparent average growth rates of 0.6-0.7 nm h −1 when the air masses traveled over land. Particle growth rates during the new particle formation (NPF) events were 3-6 times higher than the apparent particle growth during the summer period. When comparing aerosol dynamics for different overland transport times between the different stations, no major differences were found, except that in Abisko the NPF events were observed to take place in air masses with shorter overland times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing air masses traveling in an east-to-west direction with those traveling in a west-to-east direction, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics even when NPF is not evident.

Seasonal variation of atmospheric particle number concentrations, new particle formation and atmospheric oxidation capacity at the high Arctic site Villum Research Station, Station Nord

“…The observed frequencies of event days during these months at VRS, Station Nord, were relatively high compared to reported values from subarctic stations during the same months, such as Värriö (20-25 %) Kyro et al, 2014), Pallas (10-20 %) (Asmi et al, 2011) or Abisko (< 20 %) (Vaananen et al, 2013), while they overlap with the values of 30-40 % reported by Asmi et al (2016) from Tiksi, Russian Arctic. In fact, the observed new particle formation events at the subarctic stations and other Nordic stations seemed to show a spring maximum of event occurrence (Vehkamäki et al, 2004;Dal Maso et al, 2007;Kristensson et al, 2008), as opposed to the summer maximum of events observed at VRS, Station Nord. Interestingly, Asmi et al (2016) found the highest NPF event frequencies in March (50 %), whereas such frequency was only 10 % at VRS, Station Nord, during the same month.…”

“…It has long been indicated that tropospheric O 3 in the Arctic is enriched from intruding stratospheric air masses (Gregory et al, 1992;Gruzdev and Sitnov, 1993). A recent model study has also suggested that summertime photochemical production of O 3 by NO x in the Arctic could also be a dominant source (Walker et al, 2012). This was attributed to NO x emissions from the thermal decomposition of the long-lived reservoir species peroxyacetyl nitrate (PAN) during summer (Fan et al, 1994).…”

“…This was attributed to NO x emissions from the thermal decomposition of the long-lived reservoir species peroxyacetyl nitrate (PAN) during summer (Fan et al, 1994). Meanwhile, transport from midlatitude source regions could also contribute to the O 3 budget in the Arctic during autumn and winter (Walker et al, 2012). Sources of O 3 in the Arctic could therefore be a combination of different factors, including, among others, stratospheric influence, local production and transport from midlatitude sources.…”

“…This process is nevertheless limited by low temperature during winter and spring and low PAN levels during summer (Beine and Krognes, 2000). NO x also contributes via photochemistry to the local formation of tropospheric O 3 , and thus enhances O 3 levels during summer (Walker et al, 2012;Beine and Krognes, 2000).…”

Spatial extension of nucleating air masses in the Carpathian Basin

“…New particle formation and particle growth events have been identified on the regional scale in a variety of geographic locations around the world Kulmala and Kerminen, 2008). In clean environments, horizontal extension of nucleating air masses can reach up to hundreds of kilometres (Kulmala et al, , 2001Vana et al, 2004;Komppula et al, 2006;Väänänen et al, 2013).…”