Particle concentration data from: Long-term measurement of sub-3nm particles and their precursor gases in the boreal forest
Creators
- 1. nstitute for Atmospheric and Earth System Research/Physics, University of Helsinki
- 2. Laboratory of Environmental Physics, University of Tartu
Description
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 1.1–1.7 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 1.1–1.7 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 1.7–2.5 nm particles, underlining the different frequency of new particle formation between 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.
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Related works
- Is supplement to
- Journal article: 10.5194/acp-2020-719 (DOI)
Funding
- Towards cleaner air: Understanding secondary particle formation in urban environments by using multi-scale modeling 316114
- Academy of Finland
- ACTRIS-2 – Aerosols, Clouds, and Trace gases Research InfraStructure 654109
- European Commission
- ‘Centre of Excellence in Atmospheric Science - From Molecular and Biolocigal processes to The Global Climate’ 272041
- Academy of Finland
- ACTRIS PPP – ACTRIS PPP - Aerosols, Clouds and Trace gases Preparatory Phase Project 739530
- European Commission
- Centre of Excellence in Atmospheric Science From Molecular and Biolocigal processes to The Global Climate 307331
- Academy of Finland
References
- Sulo, J., Sarnela, N., Kontkanen, J., Ahonen, L., Paasonen, P., Laurila, T., Jokinen, T., Kangasluoma, J., Petäjä, T., Kulmala, M., and Lehtipalo, K.: Long-term measurement of sub-3nm particles and their precursor gases in the boreal forest, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-719, in review, 2020.