Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 5.414
IF 5-year value: 5.958
IF 5-year
CiteScore value: 9.7
SNIP value: 1.517
IPP value: 5.61
SJR value: 2.601
Scimago H <br class='widget-line-break'>index value: 191
Scimago H
h5-index value: 89
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  27 Jul 2020

27 Jul 2020

Review status
This preprint is currently under review for the journal ACP.

Long-term measurement of sub-3nm particles and their precursor gases in the boreal forest

Juha Sulo1, Nina Sarnela1, Jenni Kontkanen1, Lauri Ahonen1, Pauli Paasonen1, Tiia Laurila1, Tuija Jokinen1, Juha Kangasluoma1,2, Tuukka Petäjä1, Markku Kulmala1,2, and Katrianne Lehtipalo1,3 Juha Sulo et al.
  • 1Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, 00014 Helsinki, Finland
  • 2Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
  • 3Finnish Meteorological Institute, 00560 Helsinki, Finland

Abstract. The knowledge of the dynamics of sub-3nm particles in the atmosphere is crucial for our understanding of first steps of atmospheric new particle formation. Therefore, accurate and stable long-term measurements of the smallest atmospheric particles are needed. In this study, we analyzed over five years of particle concentrations in size classes 1.1–1.3 nm, 1.3–1.7 nm and 1.7–2.5 nm obtained with the Particle Size Magnifier (PSM) and three years of precursor vapor concentrations measured with the Chemical Ionization Atmospheric Pressure Interface Time-of-Flight mass spectrometer (CI-APi-ToF) at the SMEAR II station in Hyytiälä, Finland. The results show that the 1.1–1.3 nm particle concentrations have a daytime maximum during all seasons, which is due to increased photochemical activity. There are significant seasonal differences in median concentrations of 1.3–1.7 nm and 1.7–2.5 nm particles, underlining the different frequency of new particle formation between seasons. In particular, concentrations of 1.3–1.7 nm and 1.7–2.5 nm particles are notably higher in spring than during other seasons. Aerosol precursor vapors have notable diurnal and seasonal differences as well. Sulfuric acid and highly oxygenated organic molecule (HOM) monomer concentrations have clear daytime maxima, while HOM dimers have their maxima during the night. HOM concentrations for both monomers and dimers are the highest during summer and the lowest during winter. Higher median concentrations during summer result from increased biogenic activity in the surrounding forest. Sulfuric acid concentrations are the highest during spring and summer, with autumn and winter concentrations being two to three times lower. A correlation analysis between the sub-3nm concentrations and aerosol precursor vapor concentrations indicates that HOMs, particularly their dimers, and sulfuric acid play a significant role in new particle formation in the boreal forest. Our analysis also suggests that there might be seasonal differences in new particle formation pathways that need to be investigated further.

Juha Sulo et al.

Interactive discussion

Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Login for Authors/Editors] [Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement

Juha Sulo et al.

Juha Sulo et al.


Total article views: 259 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
175 81 3 259 4 4
  • HTML: 175
  • PDF: 81
  • XML: 3
  • Total: 259
  • BibTeX: 4
  • EndNote: 4
Views and downloads (calculated since 27 Jul 2020)
Cumulative views and downloads (calculated since 27 Jul 2020)

Viewed (geographical distribution)

Total article views: 242 (including HTML, PDF, and XML) Thereof 242 with geography defined and 0 with unknown origin.
Country # Views %
  • 1



No saved metrics found.


No discussed metrics found.
Latest update: 29 Sep 2020
Publications Copernicus
Short summary
In this study, we analyzed over five years of sub-3nm particle concentrations and their precursor vapors, identifying atmoshperic vapors important to the formation of these particles in the boreal forest. We also observed seasonal differences in both particle and precursor vapor concentrations and the formation pathways of these particles. Our results confirm the importance of organic vapors in atmospheric aerosol formation and highlight key seasonal differences that require further study.
In this study, we analyzed over five years of sub-3nm particle concentrations and their...