Part 3
Projects & Landmarks
Environment / Project


Aerosols, Clouds and Trace gases Research Infrastructure

Ground-based stations to understand past, present and predict future evolution of the atmosphere


The Aerosols, Clouds and Trace gases Research Infrastructure (ACTRIS) is a distributed infrastructure dedicated to high-quality observation of aerosols, clouds, trace gases and exploration of their interactions. It will deliver precision data, services and procedures regarding the 4D variability of clouds, short-lived atmospheric species and the physical, optical and chemical properties of aerosols to improve the current capacity to analyse, understand and predict past, current and future evolution of the atmospheric environment. ACTRIS serves a vast community of users working on observations, experiments, models, satellite data, analysis and predicting systems. It offers access to advanced technological platforms for exploration of the relevant atmospheric processes in the fields of climate change and air quality.

Included in ESFRI Roadmap in 2016, ACTRIS is striving to apply for the European Research Infrastructure Consortium (ERIC) in 2019.


Short-lived atmospheric components − aerosols, clouds, trace gases − have a residence time in the atmosphere from hours to few weeks. The short lifetimes make their concentrations highly variable in time and space and involve fast processes. They are recognised to be among the most significant anthropogenic pollutants affecting Earth’s radiation balance and the largest source of uncertainty in terms of radiative forcing impact. In parallel, short-lived atmospheric compounds have recognized adverse health effects at concentrations typically found across Europe and potentially lead to more than 400.000 premature deaths annually in the EU28. Information on concentrations and distributions of aerosols and trace gases is therefore required to reduce air pollution and related adverse effects on health and ecosystems.

ACTRIS addresses these challenges by operating at National Facilities via a combination of measurements of aerosols, clouds and reactive trace gases both near-surface and with remote-sensing systems, and ancillary measurements of meteorological and radiation quantities. ACTRIS National Facilities consist of both observational and exploratory platforms. ACTRIS relies on appropriate Central Facilities − Topical Centres for instrument calibration and development, Data Centre for data access services, data curation and storage, and Head Office for coordination and management of the RI – to provide harmonized, reliable, and documented observational data and physical access to high quality National Facilities. The Central Facilities are fundamental in providing the physical and remote access to the ACTRIS services, organising training and education, both within and outside the RI, and delivering tailored services for various user groups including scientific community, space agencies, COPERNICUS and the private sector. ACTRIS complements the Environmental RIs domain as it contributes data and services on atmospheric composition changes.

steps for implementation

In the ESFRI Roadmap since 2016, ACTRIS is the result of the long-term collaboration within the atmospheric science community sustained by a series of INFRA projects that started in 2000. The aim of the full implementation plan is to set up a Research Infrastructure service system for the complex data-stream that starts at the National Facilities and goes through quality screening and higher level data products made available through the Data Centre, and finally to the repositories that will secure long-term and global access by a large community of users. ACTRIS also offers physical access to Topical Centres, selected observational sites and exploratory facilities for users to conduct their own research.

ACTRIS is now in the Preparation Phase and will gradually move into the Implementation Phase – foreseen in 2019/2024 – to be fully operational in 2025. Interim ACTRIS Council has decided to apply for the ERIC with the aim to submit ERIC Step 1 application in early 2019.

legal status
political support
lead country
prospective member countries
The full list of research institutions involved must be found in the website of the RI
Roadmap Entry
Preparation Phase
Implementation/Construction Phase
Operation Start
estimated costs
capital value
450 M€
3 M€
6 M€
190 M€
50 M€/year

University of Helsinki and Finnish - Meteorological Institute
Helsinki, Finland &

Consiglio Nazionale delle Ricerche - CNR
Rome, Italy