Urban-Scale Associations of PM2.5 with Aerosol Light Absorption, Meteorology, and Regional Transport in a Mediterranean Area Using FAIR-Oriented Environmental Data

Atmospheric particulate-matter variability reflects the combined effects of emissions, meteorology, and regional transport, and its interpretation benefits from the integration of complementary observations. This study combines two years (2023–2024) of aerosol light absorption at 880 nm (Abs880), PM2.5, PM10, and meteorological observations from ACTRIS/EBAS and ARPA Puglia to characterize the urban-scale covariation in Lecce, southern Italy. Since the aerosol-absorption and ARPA measurements were obtained at sites separated by approximately 6.3 km, the resulting relationships are interpreted as urban-scale associations rather than as co-located source-attribution measurements. After quality assurance/quality control, UTC time normalization, daily aggregation (>75% completeness), temporal alignment, and z-score standardization for PCA, the integrated observations were examined using seasonal comparisons, linear regression, principal component analysis, and HYSPLIT backward trajectories. PM2.5/PM10 ratio showed seasonal variability in both study years, with higher mean values during the winter. The PM2.5 was positively associated with the Abs880 (R2 = 0.68 in 2023 and 0.59 in 2024), and the season-stratified regressions remained positive in all the seasonal subsets, although their strength varied. The meteorology-adjusted sensitivity models also retained a positive Abs880 coefficient after an HAC correction for serial dependence. The wind speed showed a weaker inverse association with PM2.5, whereas the temperature and the relative humidity showed weak pairwise associations. A PCA identified a common covariance direction among PM2.5, PM10, and Abs880, with additional meteorological structure in the six-variable sensitivity analysis. Two representative episodes contrasted an enhanced Abs880 under low-wind conditions with a spring Saharan-dust intrusion. Overall, this study characterizes the relationships among particulate matter, aerosol light absorption, meteorology, and regional transport over the 2023–2024 observation period. FAIR-oriented data practices and interoperable monitoring infrastructures provide the methodological framework that enables the integration, traceability, and reproducibility of these analyses.