The project has clearly increased our understanding of clusters and nano-particles in the atmosphere and their formation on a molecular level.
During the project, the ER has contributed to 33 peer-reviewed scientific articles (+several more are submitted or in preparation). The ER was active in supervising MSc and PhD students, organizing a conference, participating in workshops, project meetings and conferences, giving altogether 17 presentations, peer-reviewing articles and doing science outreach.
These results have several wider implications. Many other groups worldwide have started measurements of sub-3 nm particles, further increasing the knowledge on their concentrations both in the atmosphere and also in other contexts, like indoor environments. Identifications of the new nucleation and growth mechanisms enable including them in global aerosol models, and thus refining the estimates of the radiative forcing due to aerosols. Gordon et al. (2016) already showed that including pure biogenic nucleation could lead to a reduction of 27% in estimates of anthropogenic aerosol radiative forcing.
Additionally, the project has had a remarkable impact on the academic career prospects of the ER. The mobility period allowed learning new methods and starting new collaborations. The returning phase was successful in integrating the ER back to Univ. Helsinki, where she started as associate professor after the completion of the project.
References:
Gordon, H. et al. Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation. PNAS, 2016
Jokinen, T. et al. Solar eclipse demonstrating the importance of photochemistry in new particle formation, Scientific Reports, 2017
Kirkby, J., et al. Ion-induced nucleation of pure biogenic particles. Nature, 2016
Kontkanen, J. et al. High concentrations of sub-3 nm clusters and frequent new particle formation observed in the Po Valley, Italy, during the PEGASOS 2012 campaign, Atmos. Chem. Phys., 2016
Kontkanen, J. et al. Measurements of sub-3202fnm particles using a particle size magnifier in different environments: from clean mountain top to polluted megacities, Atmos. Chem. Phys., 2017
Lehtipalo, K. et al. The effect of acid-base clustering and ions on the growth of atmospheric nano-particles. Nat. Commun., 2016
Rose, C. et al. Observations of biogenic ion-induced cluster formation in the atmosphere. Science Advances, 2018
Sarnela, N. et al. Sulphuric acid and aerosol particle production in the vicinity of an oil refinery, Atmos. Environ., 2015
Stolzenburg, D. et al. Rapid growth of organic aerosol nanoparticles over a wide tropospheric temperature range. PNAS, 2018
Tröstl, J. et al. Low-volatility organic compounds are key to initial particle growth in the atmosphere. Nature, 2016
Wagner R. et al. The role of ions in new particle formation in the CLOUD chamber, Atmos. Chem. Phys., 2017
Yan C. et al. The role of H2SO4-NH3 anion clusters in ion-induced aerosol nucleation mechanisms in the boreal forest, Atmos. Chem. Phys., 2018
