1Department of Physics, University of Helsinki, 00014 Helsinki, Finland
2Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
3Laboratoire de Météorologie Physique, UMR6016, CNRS/UBP, 63178
4Shanghai Key Laboratory of Atmospheric Particle Pollution and
Prevention (LAP3), Department of Environmental Science & Engineering,
Fudan University, 200433 Shanghai, China
5Joint International Research Laboratory of Atmospheric and Earth
System Sciences, School of Atmospheric Sciences, Nanjing University, 210023
6School of Environmental Science and Engineering, Nanjing University of
Information Science and Technology, Nanjing, China
7Department of Atmospheric Science, University of Alabama in
Huntsville, Huntsville, Alabama
Received: 23 Sep 2016 – Discussion started: 04 Oct 2016
Abstract. The measurement of sub-3 nm aerosol particles is technically challenging. Therefore, there is a lack of knowledge about the concentrations of atmospheric sub-3 nm particles and their variation in different environments. In this study, the concentrations of ∼ 1–3 nm particles measured with a particle size magnifier (PSM) were investigated at nine sites around the world. Sub-3 nm particle concentrations were highest at the sites with strong anthropogenic influence. In boreal forest, measured particle concentrations were clearly higher in summer than in winter, suggesting the importance of biogenic precursor vapors in this environment. At all sites, sub-3 nm particle concentrations had daytime maxima, which are likely linked to the photochemical production of precursor vapors and the emissions of precursor vapors or particles from different sources. When comparing ion concentrations to the total sub-3 nm particle concentrations, electrically neutral particles were observed to dominate in polluted environments and in boreal forest during spring and summer. Generally, the concentrations of sub-3 nm particles seem to be determined by the availability of precursor vapors rather than the level of the sink caused by preexisting aerosol particles. The results also indicate that the formation of the smallest particles and their subsequent growth to larger sizes are two separate processes, and therefore studying the concentration of sub-3 nm particles separately in different size ranges is essential.
Revised: 11 Jan 2017 – Accepted: 22 Jan 2017 – Published: 13 Feb 2017
Kontkanen, J., Lehtipalo, K., Ahonen, L., Kangasluoma, J., Manninen, H. E., Hakala, J., Rose, C., Sellegri, K., Xiao, S., Wang, L., Qi, X., Nie, W., Ding, A., Yu, H., Lee, S., Kerminen, V.-M., Petäjä, T., and Kulmala, M.: Measurements of sub-3 nm particles using a particle size magnifier in different environments: from clean mountain top to polluted megacities, Atmos. Chem. Phys., 17, 2163-2187, doi:10.5194/acp-17-2163-2017, 2017.