Exposure to urban nanoparticles at low PM1 concentrations as a source of oxidative stress and inflammation

Exposures to fne particulate matter (PM1) have been associated with health impacts, but the understanding of the PM1 concentration-response (PM1-CR) relationships, especially at low PM1, remains incomplete. Here, we present novel data using a methodology to mimic lung exposure to ambient air (2< PM1 < 60 µg m−3), 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 PM1-CR curves are interpreted as a result of the interplay between the aerosol total oxidative potential (OPt) and its distribution across particle size (dp). A dp-dependent condensation sink (CS) is assessed together with the distribution with dp of reactive species . Urban ambient aerosol high in OPt, as indicated by the DTT assay, with (possibly copper-containing) nanoparticles, shows higher pro-infammatory and oxidative responses, this occurring at lower PM1 concentrations (< 5 µg m−3). Among the implications of this work, there are recommendations for global eforts to go toward the refnement of actual air quality standards with metrics considering the distribution of OPt with dp also at relatively low PM1.