Seasonal distribution of airborne trace elements and water-soluble ions in São Paulo Megacity, Brazil

Abstract

This study deals with the seasonal distribution of Al, Ca, Cu, Fe, K, Mg, Na, Pb and Zn and water soluble ions (Cl-, PO4 3-, NO3 -, SO4 2-, HCOO-, CH3COO-, oxalate, succinate, Na+, NH4 +, K+, Mg2+ and Ca2+) found in PM10 samples (particulate matter less than 10 mm in diameter) São Paulo City, Brazil, (April 2003-May 2004). Higher atmospheric levels were found for SO4 2-, NO3 -, Cl- and PO4 3- while the main organic anions were oxalate and formate. Atmospheric levels for elements were: Fe > Al > Ca > K > Na > Mg > Zn > Cu > Pb. Some sources were predominant for some species: (i) fuel burning and/or biomass burning (NO3 -, HCOO-, C2O4 2-, K+, Mg2+, Ca2+, Fe, Pb, Zn, Al, Ca, K and Mg), (ii) gas-to-particle conversion (SO4 2- and NH4 +) and (iii) sea salt spray (Cl-, Na+ and Na).