High-temporal-resolution chemical characterization of PM0.1 at a Mediterranean background site

Abstract

Ultrafine particles can penetrate sensitive human organs and are strongly associated with adverse health effects. This study presents the first high-temporal-resolution chemical characterization of PM 0.1 at a Mediterranean background site under conditions in which photochemistry and transport are dominant processes. PM 0.1 mass averaged 0.5 μg m −3 and exhibited sharp midday increases from frequent SO 2 -driven new particle formation events occurring within 50 km of the site. PM 0.1 exhibited weak correlation ( R 2 = 0.25) with PM 1 , though organic aerosol and sulfate dominated both. Elemental analysis identified elevated Ca and Fe in PM 0.1 , potentially linked to shipping, whereas PM 2.5 Ca was mostly associated with dust/soil. Volcanic plumes from Mt. Etna (750 km away) were also captured. During these events, SO 2 levels increased tenfold and were accompanied by elevated levels of Zn, Pb, and As in PM 0.1 , indicating persistence of heavy metals in PM 0.1 even over long-range transport.