Sci. total environ. Sci. total environ. Compositional changes of PM2.5 in NE Spain during 2009–2018: a trend analysis of the chemical composition and source apportionment Veld Marten I. Alastuey Andrés Pandolfi Marco Amato Fulvio Pérez Noemí Reche Cristina Via Marta Minguillón María Cruz Escudero Miguel Universidad de Zaragoza Querol Xavier 2021 research-article