In the Atmosphere Biosphere Cryosphere (ABC) Interactions group, we combine both theoretical and experimental research methods to elucidate the key processes leading to the formation of new particles in the atmosphere. These processes represents the most unknown aspects underlying the Earth's climate.
We focus our research in pristine regions of the globe that better mimic the primordial condition of the Earth's atmosphere. We aim at obtaining a quantitative picture of the Earth's atmosphere during those periods which is essential to provide a correct understanding of our current climate and of its future path.
We have conducted measurement campaigns at high-measurement sites, i.e. the Alps (Jungfraujoch, 3.471 m a.s.l), the Himalaya (Nepal Climate Observatory at Pyramid, 5.079 m a.s.l), the Andean Mountains (Chacaltaya Observatory, 5.421 m a.s.l) and the Canary Islands (Izaña Atmospheric Observatory, 2.373 m a.s.l). Additionally, we are also involved in measurements campaigns taking place in polar regions, i.e. at the Zeppelin station in the Svalbard, and aboard the MOSAiC expedition in the Arctic Ocean.
A large part of our research activities also takes place in the Finnish Boreal Forest (i.e. at the Hyytiälä measurement site), where we focus our research on new particle formation from biogenic precursors, e.g. monoterpenes, and in the Po Valley (i.e. the San Pietro Capofiume, measurement site), one of the most polluted place in Europe.
Finally, our members are also playing an active roles in chamber studies like the Cosmics Leaving Outdoor Droplets (CLOUD) experiment run at CERN, Geneva.
The arc of the Himalayas has an approximate length of 2.400 km, which is roughly two times the length of Finland. Its vegetation largely varies across the valleys ranging from tropical deciduous forests in the foothills, to temperate forests in the middle altitudes. Higher up, coniferous, sub-alpine, and alpine forests are often present.
In December 2014, we deployed a set of instruments at the NCO-P to measure the size distribution of particles (diameter d > 1 nm) and ions (d > 0.8 nm), as well as the chemical composition of the cluster ions. This included a particle size magnifier (PSM), a neutral cluster and air ion spectrometer (NAIS) and an atmospheric pressure interface time-of-flight (APi-TOF) mass spectrometer. In addition, a nitrate-based chemical ionization unit (CI-APi-TOF) permitted the measurement of the neutral compounds. These instruments were complemented by the long-term instrumentation running at the NCO-P, such as a scanning mobility particle sizer (SMPS) and ozone and SO2 monitors.
We show that up-valley winds funnel gaseous aerosol precursors to higher altitudes. During this transport, these are oxidized into compounds of very low volatility, which rapidly form a large number of aerosol particles. These are then transported into the free troposphere, which suggests that the whole Himalayan region may act as an ‘aerosol factory’ and contribute substantially to the free tropospheric aerosol population. Aerosol production in this region occurs mainly via organic precursors of biogenic origin with little evidence of the involvement of anthropogenic pollutants.
The Southern Hemisphere High Altitude Experiment on Particle Nucleation and Growth (SALTENA), is an international field campaign that took place from December 2017 to May 2018 at the Global Atmosphere Watch (GAW) station Chacaltaya in the Bolivian Andes at 5.240 m MSL. The overall goal of the campaign was to understand the sources, formation and growth mechanisms, and properties of aerosols at this high-altitude research station. The 6-month period was chosen in order to capture the (parts of the) wet (until ∼March), transition (∼April), and dry season (∼May and onward) and the peak season for new-particle-formation events.
The main site in the SALTENA campaign is the Global Atmosphere Watch (GAW) station CHC located at Chacaltaya (5,240 m a.s.l.; 16.35°S, 68.13°W). The station is located on the northwest face of the mountain with direct view to the metropolitan area of La Paz–El Alto to the southwest. The site samples air masses arriving from the Amazon to the east, the Altiplano (a large high-altitude plateau between 3.800 and 4.100 m MSL) to the west, the Pacific Ocean farther west, and from the La Paz–El Alto metropolitan region (1.7 million inhabitants) located 17 km to the south but 1.1 km below CHC.
The comprehensive instrumentation deployed across three measurement sites during the SALTENA campaign permitted an unprecedented look at the changes in the physico-chemical properties of polluted air as it is transported from anthropogenic source regions in the Altiplano, including the metropolitan areas of La Paz–El Alto, to the high-altitude station CHC and the free troposphere. The observations will enable further investigation of (i) specific urban sources of pollution in the undersampled Southern Hemisphere; (ii) anthropogenic aerosol ageing processes including secondary formation under strong solar radiation conditions due the high altitude; (iii) the role of atmospheric pollutants in NPF and growth of particles to sizes relevant for cloud formation; and (iv) the potential climatic and environmental impacts of the pollution across the broader Altiplano and Andes region of the South American continent.
From March to May 2022 we have performed measurements campaign at the Izaña Atmospheric Observatory (IZO; 2373 m a.s.l.), which is located on the island of Tenerife, Canary Islands (Spain).
The aim of this campaign is to understand the gas precursors responsible for new particle formation (NPF) process in pristine environment. The Izaña Atmospheric Observatory station is located far away from any significant industrial activities and so free of local anthropogenic influences. The clean air and pristine skies offer excellent conditions for in-situ measurements of trace gases, aerosols and pristine NPF observations.
A Vocus-PTR-TOF was used to measure VOC (volatile organic compounds) and oxidation products of DMS (dimethyl sulphide). An APi-TOF equipped with a MION inlet was used to detect ion clusters (using API mode), less oxygenated VOC (using Br- as the reagent ion), and sulphuric acid (H2SO4) and more oxygenated VOC (including highly oxygenated organic molecules, HOM; using NO3– as the reagent ion). A NAIS and a PSM was deployed for number concentration and size distribution of atmospheric ions and neutral particles with a mobility diameter of 0.8-42 nm and number concentration of particle with a mobilitiy diameter of 1.25-2.5 nm, respectively.
The campaign is a TNA (TransNational Access) Observation campaign, under the umbrella of the ATMO-ACCESS project (Sustainable Access to Atmospheric Research Facilities, more info https://izana.aemet.es/atmo-access-isaf/), supported by the H2020 European Research Council (grant no. 850614, 101008004).