The OPAS (Operational alert Products for ATM via SWIM) SO2LH service supports the aviation safety control bodies in charge of providing advisory information related to volcano, typically the VAACs, which need situation awareness and dataset to proceed data integration and provide SIGMET, AIRMET and special NOTAM like ASHTAM and SO2TAM. This service also supports other stakeholders relying on the knowledge of the state of the atmosphere and the situation awareness of flights, typically atmospheric dispersion modellers, airlines and aircraft manufacturers. These stakeholders need estimates and forecasts of exposure dose due to SO2 emissions to proceed re-routing in order to avoid significant health effect to passengers / crew and impact on the service life of certain aircraft component (see ICAO ConOps of the 12th Nov. 2018). More details about the Business context can be find in the Final Technical Report (FTR) of the Engage-KTN OPAS project (https://engagektn.com/wp-content/uploads/2020/12/C6-OPAS-final-technica…).