CORDIS - EU research results

Molecular steps of gas-to-particle conversion: From oxidation to precursors, clusters and secondary aerosol particles.

Periodic Reporting for period 4 - GASPARCON (Molecular steps of gas-to-particle conversion: From oxidation to precursors, clusters and secondary aerosol particles.)

Reporting period: 2021-08-01 to 2022-01-31

Cloud droplets form when supersaturated water condenses on tiny seed particles, called aerosol particles. Properties of aerosol, including the sizes, compostion and concentration of aerosol particles largely determine the optical properties and lifetime of clouds affecting Earhts radiation budget andprecipitation patterns and thereby climate. Aerosol particles are emitted to atmosphere as primary particles - including dust, sea salt, soot, pollen etc - or are formed from atmospheric condensable vapours via gas-to-particle conversion.

Vapours responsible on gas-to-particle conversion are only vaguely known. Also the chemical pathways forming those condensable vapours are not fully understood. The gases, which are converted to condensable vapours have both natural and anthoropogenic sources. Understanding the role of different gases and vapours, their sources, their chemical reactions in the atmosphere as well as details of the physical mechanisms leading to production of small nanometer sized clusters and cluster growth above ca 100 nanometer sizes where they can act as cloud seeds is crucial. Why it is crucial, is because aerosol - cloud interactions form the largest uncertainty in climate predictions. This project aims to resolve the mechanisms of aerosol formation around the Globe in different environments from Antarctica to oceans, forests, agricultural areas, urban areas, up to Arctic, sea ice covered regions.

New knowldge produced in this project can be utilized in Global Climate models currently lacking for correct description of secondary aerosol formation processes. This, at time, will enable more accurate model description how cloud properties, and thus radiative budget and climate will change in the future. Crucial information for societies and the future of Earths ecosystems including mankind.

Overal objectives are to develope state-of-art detection techniques for atmospheric vapour and cluster detection, beyond the capabilities of present day commercial technology and to deploy these techniques in laboratory and field studies around the globe to resolve mechanisms and chemical compounds involved in secondary aerosol and cloud condensation nuclei formation in different atmospheric environments around the world.
We have developed and introduced a new methods for detection of aerosol precursor vapours with wide spectrum and high sensitivity. For experimental laboratory research purposes, we have designed and constructed a large flow reactor which allows simulating the atmospheric chemical reactions and aerosol formation in controlled conditions.

We have performed multiple experiments (altogether ca 5 months 24/7 research) in CLOUD facility in CERN where we simulate atmosphere with precised controlled conditions. These experiments allow us to interpret our field observations and create parametrizations of aerosol formation processes to be used in global climate models.

We have started long term monitoring programs for aerosol precursor gases and aerosol formation in two sites in Finland - SMEAR II station in Southern Finland boreal forest and sub-arctic SMEAR I station in Finnish Lapland - as well as in Ny Ålesund, Svalbard, 900km from Norht Pole and with limited measurement setup at Marambio Base in Antarctic peninsula and at Villum Research Station, Northern Greenland.

Besides long term measurements, 1-6 month lasting field campaigns have been performed in

1) Ny-Ålesund, Svalbard, Norway.
2) Värriö SMEAR I, Finland.
3) Marambio Base, Antarctica.
4) Cyprus.
5) Budapest, Hungary.
6) Reunion-island, Indian Ocean.
7) Helsinki, Finland.
8) Mace Head, Ireland.
9) Neumayer III, Antarctica.
10) Parainen, Finland.
11) Flight campaigns with Cessna-185 in southern Finland.

To summarize, we have resolved the molecular steps of secondary new particle formation in different atmospheric environments in accordance with the project plan. Further we have amended the understanding on atmospheric oxidation processess and developed new experimental methods and instrumentation for future research needs.
We have already resolved cluster formation and growth mechanisms in high detail on molecular level in Antarctic and Arctic environments, some coastal/oceanic environments and obtained at least conceptual unterstanding on these mechanisms in several other locations. We have also found new chemical mechanisms involved in production of condensable vapours responsible on aerosol formation. By the end of the project, it is foreseen that our observations can be scaled and applied to describe most environments on the globe accurately enough to be implemented in large scale modeling frameworks including global climate models. New measurement tehniques will serve the research community in the future beyond this project.
Measurement setup for cluster and particle formation studies in Ny-Ålesund, Svalbard 2017.