Air quality status and trends over the Metropolitan Area of São Paulo, Brazil as a result of emission control policies - Carvalho, Vanessa Silveira Barreto; Freitas, Edmílson Dias de; Martins, Leila Droprinchinski; Martins, Jorge Alberto; Mazzoli, Caroline Rosario; Andrade, Maria de Fátima (Environmental Science & Policy, 2015)