Pan-European Research Infrastructure for the observation of Aerosol, Clouds and Trace Gases (ACTRIS)

ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure) is a pan-European initiative consolidating actions amongst European partners producing high-quality observations of aerosols, clouds and trace gases. Different atmospheric processes are increasingly in the focus of many societal and environmental challenges, such as air quality, health, sustainability and climate change. ACTRIS aims to contribute in the resolving of such challenges by providing a platform for researchers to combine their efforts more effectively, and by providing observational data of aerosols, clouds and trace gases openly to anyone who might want to use them.

The challenge

Short-lived atmospheric components – aerosols, clouds, trace gases – are some of the most significant anthropogenic pollutants affecting Earth’s radiation balance, and having a big impact on climate, health and ecosystems. Long0term data on concentrations ans distributions of aerosols and trace gases are instrumental to reduce air pollution and related adverse effects on health and environment.

ACTRIS services

  • High-class and quality checked atmospheric data available to all users free of charge;
  • Higher level data services;
  • Instrumental calibrations;
  • Access to best research environments and expertice at ACTRIS Topical Centers and at selected ACTRIS National facilities.

ACTRIS will be the platform for atmospheric research, serving a vast community of users working in research, space agencies, operational services, public and private sectors.

ACTRIS components

ACTRIS consists of numerous National Facilities and Central Facilities.

ACTRIS National Facilities have a combinations of near-surface and remote-sensing systems to provide ACTRIS data and high quality research environments. The ACTRIS community includes 21 European countries (Fig. 1).

ACTRIS Central Facilities cover Head Office, Data Centre, and Topical Centres for in situ measurments and remote sensing of aerosol particles, cloud microphysics and reactive trace gases.Together these assure the quality, harmonization, delivery, and storage of ACTRIS data.


With the successful implementation of the ACTRIS Preparatory Phase Project (PPP), funded by the EU under the Horizon2020 program, the preparatory phase of building the scientific infrastructure was completed and its evolving into becoming a European Research Infrastructure Consortium (ERIC) began. In January 2019, the Interim ACTRIS Council (IAC), Bulgaria being a member, gave a mandate to Finland to submit ACTRIS ERIC Step 1 documents to the European Commission, which was done on 1 March 2019. In the autumn of 2019, ACTRIS received positive feedback from the EC, which recognizes that the scientific infrastructure will enable researchers to generate substantial new knowledge, which can lead to the development of sustainable solutions to societal needs. The EC acknowledges ACTRIS as a major contributor to solving important environmental problems.

On January 1, 2020, a four-year ACTRIS Implementation project (ACTRIS IMP) was started, whose main goal is supporting the ACTRIS implementation through establishing by 2025 a long-term sustainable research infrastructure with well-functioning operational services. The ACTRIS IMP project will elevate ACTRIS to a new level of maturity and will define the necessary coordinating structures for coherent implementation actions, both at national and European levels.

In March 2021 IAC approved the necessary ERIC Step 2 documents and gave a mandate to Finland to start the official ministerial signature round for ERIC Step2 Application. The expected start of ACTRIS ERIC is in the end of 2021.

Fig. 1. Map of EU States participating by 30 December 2018 in the European research infrastructure ACTRIS.