Air pollution remains the largest environmental health risk in Europe. In 2023, 94% of the EU urban population was exposed to PM2.5 concentrations above the WHO guideline, contributing to an estimated 182,000 premature deaths. A key scientific challenge is the strong spatial and temporal variability of air pollution: emissions, atmospheric chemistry, meteorology and transport interact from regional scales to urban hotspots, while no single observing system captures these processes across all relevant scales.
Improving this evidence base is central to European air-quality policy. The revised Ambient Air Quality Directive (AAQD), complementing the European Green Deal and implementing the EU Zero Pollution Action Plan, brings EU air-quality standards closer to WHO recommendations and strengthens air-quality monitoring, modelling and planning. This requires more accurate, comparable and timely information on regulated pollutants such as PM2.5, PM10, NO2, SO2 and O3, as well as pollutants of emerging concern, and improved understanding of their sources.
This new and forming ESSI Alliance will bring together VISIONAIR, funded under the Horizon Europe topic Innovative and advanced monitoring and modelling systems for revised air quality policies, with complementary projects of 500k EUR each to be selected through ESA’s FutureEO programme under the future call: Earth Action Atmosphere Cluster Opportunities – Advancing Air Quality Assessment with a Multi-Scalar, Multi-Mission Approach 2026.
Consortia are currently invited to submit proposals for the ESA activity and are encouraged to consider potential scientific synergies with VISIONAIR when developing their proposed activities. Once the ESA project is selected, a formal Alliance kick-off will be organised and partners will be invited to define their own joint activities and outputs. These might include:
- Connecting observations across scales, linking multi-mission satellite observations with urban and in-situ measurements;
- Harmonising and validating atmospheric datasets and methods across satellite, ground-based and modelling approaches;
- Improving source attribution and regional-to-urban transport modelling through combined observations and chemical transport models;
- Connecting atmospheric composition with exposure and health, exploiting synergies with VISIONAIR’s urban observations and health-impact assessments;
- Developing shared outputs, including intercomparison studies, harmonised datasets, open methodologies and tools, joint publications and scientific recommendations.
Further exchanges during Horizon Europe Annual Meetings, ESA Atmosphere Science Cluster meetings and relevant scientific workshops and conferences are encouraged to identify additional cooperation based on the evolving scientific needs and added value for participating projects.