CAMS products for analyzing atmospheric dynamics to develop QA indicators at regional scale

Air pollution episodes involving fine particulate matter (PM₂.₅) are tightly linked to synoptic meteorology, which regulates accumulation and dispersion. This study evaluates the ability of Copernicus Atmosphere Monitoring Service (CAMS) reanalyses (2015–2023) to support a daily-scale classification of circulation regimes relevant for air quality in eastern France. CAMS near-surface parameters (temperature, relative humidity, wind) were compared with the high-resolution SAFRAN reanalyses, and CAMS sea-level pressure fields were used to derive a reproducible classification benchmarked against Großwetterlagen.The present study highlights three main regimes. Anticyclonic situations promote strong PM₂.₅ accumulation under stable, poorly ventilated conditions. Low-pressure regimes enhance dispersion through stronger winds and mixing, limiting concentrations. An intermediate regime, less documented in previous classifications, combines moderate pressure gradients and variable transport pathways, producing heterogeneous pollution levels and occasional long-range particle transport.Results show good climatological agreement between CAMS and SAFRAN, with CAMS reproduces the main meteorological and synoptic patterns, while smoothing finer-scale contrasts. The classification explains both seasonal patterns and interannual variability, while underlining the persistent contribution of local emissions (traffic, heating, industry).Overall, CAMS provides a robust synoptic-scale framework for meteorological typologies relevant to air quality. Although its coarse resolution constrains intra-urban representation, coupling with high-resolution urban models could substantially enhance the diagnosis, forecasting, and management of particulate pollution episodes. This approach would not only improve the characterization of wintertime events but also capture the broader annual particle season, thereby providing more robust support for the development of effective mitigation strategies.