Genotoxic effects in blood cells from mice exposed for several periods to urban air pollution in São Paulo City - Freire-Maia, Dertia V.; Saldiva, Paulo Hilário Nascimento; Martins, Lourdes C.; Pires, Adriana; Basilio, Ana C.; Braga, Alfésio (Congresso Brasileiro de Ecotoxicologia, 2004)