Exposure to urban nanoparticles at low PM$$_1$$ concentrations as a source of oxidative stress and inflammation
Francesca Costabile, Maurizio Gualtieri, Matteo Rinaldi, Silvia Canepari, R. Vecchi, Lorenzo Massimi, Gianluca Di Iulio, Marco Paglione, Luca Di Liberto, Emanuela Corsini, M. C. Facchini, Stefano Decesari
Abstract
Exposures to fine particulate matter (PM[Formula: see text]) have been associated with health impacts, but the understanding of the PM[Formula: see text] concentration-response (PM[Formula: see text]-CR) relationships, especially at low PM[Formula: see text], remains incomplete. Here, we present novel data using a methodology to mimic lung exposure to ambient air (2[Formula: see text] 60 [Formula: see text]g m[Formula: see text]), with minimized sampling artifacts for nanoparticles. A reference model (Air Liquid Interface cultures of human bronchial epithelial cells, BEAS-2B) was used for aerosol exposure. Non-linearities observed in PM[Formula: see text]-CR curves are interpreted as a result of the interplay between the aerosol total oxidative potential (OP[Formula: see text]) and its distribution across particle size (d[Formula: see text]). A d[Formula: see text]-dependent condensation sink (CS) is assessed together with the distribution with d[Formula: see text] of reactive species . Urban ambient aerosol high in OP[Formula: see text], as indicated by the DTT assay, with (possibly copper-containing) nanoparticles, shows higher pro-inflammatory and oxidative responses, this occurring at lower PM[Formula: see text] concentrations (< 5 [Formula: see text]g m[Formula: see text]). Among the implications of this work, there are recommendations for global efforts to go toward the refinement of actual air quality standards with metrics considering the distribution of OP[Formula: see text] with d[Formula: see text] also at relatively low PM[Formula: see text].