Evaluation of the role of natural and anthropogenic sources on acellular and in vitro TOXicity INdicators of AtmospherIc aerosol (TOX-IN-AIR): preliminary results

Introduction: Fine particulate matter (PM_2.5) is a significant risk for public health. The mechanisms underlying its toxicity are still not fully understood, with contrasting results across acellular, cellular, and in vivo toxicity metrics. The TOX-IN-AIR project aims to analyse correlations between toxicity indicators and chemical composition, considering seasonal and site dependencies, and assess the contributions of natural and anthropogenic sources and their nonlinear interactions.

Methods: Two campaigns were conducted in winter and summer in Lecce, Italy. The Mobile Laboratory for Gas and Aerosol Measurements (MAGA) and the Environmental-Climate Observatory (ECO) platforms were used for the urban and urban background sites, respectively. PM_2.5 samples were collected on Teflon and quartz filters. Particle size distributions, meteorological data, and gas concentrations were measured online. In the laboratory, the PM_2.5 fraction was weighed, and subsequently, the chemical composition was measured by ED-XRF. The filters were then fractionated and subjected to a) chemical characterization; b) acellular determination of oxidative potential; and c) cellular in vitro analysis.

Results and conclusions: The PM_2.5 mass concentrations were very similar between the ECO and MAGA sites during both campaigns. Particle number concentrations (diameter ≤2.5 μm) were higher at the urban site compared to the suburban site, particularly during the winter period. Coarse particles (diameter≥ 2.54μm) were similar at the two sites. Peaks in coarse particles were observed during three days in both campaigns, attributed to long-range Saharan dust transport. The results of source apportionment by using the PMF receptor model will be presented.

This work was co-funded by Next Generation EU – Mission 4 – Ministry of University and Research (MUR) – Call PRIN 2022 PNRR – Project TOX-IN-AIR, P2022JKPS.