Plasma-based technique applied to the determination of 21 elements in ten size fractions of atmospheric aerosols

Abstract

A study was undertaken to quantify metals and metalloids content in size-resolved atmospheric particles sampled in the megacity of Buenos Aires, Argentina. Ten size distributed aerosol with aerodynamic diameters of <0.10, 0.10–0.18, 0.18–0.32, 0.32–0.56, 0.56–1.0, 1.0–1.8 1.8–3.2, 3.2–5.6, 5.6–10 and 10–18 μm collected on Teflon filters by using a micro-orifice uniform deposition impactor (NanoMOUDI sampler) were analyzed. An acid mixture containing HCl, HNO3 and HF (6:2:1) was used for microwave (MW) assisted digestion of each airborne particulate matter (APM) fraction. Twenty-one elements namely, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Ti, V and Zn were determined by plasma-based techniques namely inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) in the digested size-distributed aerosols. A predominance contribution (~60%) of fine particle (PM1) was observed in the total aerosol mass. Mass size distribution together with Cu, Li and V exhibited bimodal distribution at 0.32–0.56 and 1.8–3.2 µm ranges. Eleven elements exhibited unimodal distributions with rock forming elements (Ca, Fe, Mg, Ti) and Ba peaking at 1.8–3.2 µm while As, Cd, Pb, Sb, Se and Zn peaking at 0.32–0.56 µm. These results are in line with findings from other cities which indicate that mineral dust has a higher contribution in the coarser fraction, while particles from fuel combustion and other traffic-related emissions are more relevant in the finer fraction.