On the challenges for improving air quality in South American megacities - Padilla, Liana Giselle Murcia; Martins, Jorge Alberto; Martins, Leila Droprinchinski; Roa, Néstor Yesid Rojas; Rafee, Sameh Adib Abou; Andrade, Maria de Fátima (Quadrennial ICACGP Symposium, 2014)