The quality of life in large urban centers is directly affected by the air quality there. Atmospheric monitoring is therefore imperative, and bioassays using plant models to detect the effects of genotoxic agents are recognized as giving excellent results. The present study utilized Trad-MCN to evaluate the genotoxic effects of atmospheric pollutants in the city of Feira de Santana, Bahia State, Brazil, in three locations with varying traffic loads. Inflorescences were collected on a monthly basis from plants growing in these locations in both passive and active monitoring regimes. The occurrence of micronuclei (MCN) was found to be proportional to vehicular flux under both monitoring regimes; with the plants being accompanied by active monitoring demonstrating the greatest sensitivity to atmospheric contamination. The results indicated that locations with the most intense vehicular traffic demonstrated significant atmospheric contamination by pollutants able to damage DNA.