ARIES (Atmospheric Release Impact Evaluation System) is a system consisting of different atmospheric dispersion models that allow to track - on different geographical scales - the fate of radioactive species accidentally released into the atmosphere. ARIES is a key component within the Nuclear Emergency Centre of the Institute for Environmental Protection and Research (Rome, Italy). The system simulates releases that occur from any point within a domain of about 16 million km2, including almost all Europe.

Enviroware has designed and developed ARIES introducing state-of-the-science atmospheric dispersion models (ADMs), and implementing a modern web interface that, potentially, will allow the use of the system from a remote location. Three different ADMs are included in ARIES: the long-range Lagrangian particle model APOLLO2, the meso-scale Lagrangian particle model LAPMOD, and the short-range analytical model TOXFLAM. The diagnostic meteorological model CALMET is also included in ARIES as preprocessor for LAPMOD. The output of the ADMs are used to calculate groundshine, cloudshine and inhalation doses through algorithms included in ARIES.

ARIES contains a database of radionuclides as well as a database of the European nuclear power plants (NPPs). The accidental release may happen from a NPP or from any other point within the ARIES domain (longitude from 20W to 40E, latitude from 30N to 70N), as for example in case of terrorist attack.

A climatological version of ARIES has also been developed as a desktop software. It is used to get the impact of a radioactive cloud in probabilistic terms.