Multi-isotopic fingerprints (Pb, Zn, Cu) applied for urban aerosol source apportionment and discrimination

• Discrimination of pollutant sources in the atmosphere using Pb, Cu and Zn isotopes • Association of aerosol isotopic compositions , meteorology and trace compounds • A model based on Pb and Zn isotopic fingerprints for source apportionment Air pollution imposes serious health risks to urban populations and currently is the major environmental threat to the public health worldwide. In this context, discrimination and tracing of pollutants in atmosphere is a great challenge nowadays. This study reports the simultaneous use of Pb, Cu and Zn Multi-Isotopic Systems (MIS) to identify and discriminate pollutant sources of atmospheric particulate matter (PM) collected in day and nighttime temporal resolution in São Paulo city, Brazil. The isotopic fingerprints of road dust and tires (δ 66 Zn = 0.00 to +0.20‰ and 206 Pb/ 207 Pb = 1.16 to 1.19) were differentiated from vehicular traffic (δ 66 Zn = −0.60 to +0.00‰ and 206 Pb/ 207 Pb < 1.19) and PM from an industrial area (δ 66 Zn < −0.60‰ and 206 Pb/ 207 Pb > 1.20). Isotopic signatures of cement (δ 66 Zn = 0.00 to +0.30‰ and δ 65 Cu NIST = +0.30 to +0.61‰) were distinguished from road dust (δ 65 Cu = +0.08 to +0.25‰) and vehicular traffic (δ 65 Cu NIST = +0.46 to +0.59‰). The isotopic compositions found in PM for Pb ( 206 Pb/ 207 Pb = 1.156 to 1.312, n = 113), Zn (δ 66 Zn = +0.43 to −1.36‰, n = 62) and Cu (δ 65 Cu = +0.12 to 0.66‰, n = 7) are comparable with those measured on the main pollutant sources found in urban areas. Zinc and lead isotopic compositions of PM from Sao Paulo showed diurnal variations indicating the industrial contributions carried by cold fronts and road dust suspension associated to high wind speeds and traffic pattern. A ternary mixing model based on Pb and Zn isotopic fingerprints of the main pollutant sources were developed to account vehicular traffic (70%), industrial area (10%) and another uncharacterized source (20%) contributions, possibly associated with industrial and biomass burning emissions. Our findings validate the use of Pb, Cu and Zn MIS to source apportionment studies in the atmosphere with multiple and complex pollutant sources.