PM_2.5 decadal changes in Brazil: influence of vehicular fleet growth and policy to control vehicular emissions

Previous studies suggest that Programs to Control Vehicular Emission (PCVE) restrictions have succeeded in improving air quality. However, evidence about PCVE’s long-term effects in developing countries in the Southern Hemisphere is still lacking. We analyzed the influence of PCVE restrictions on PM_2.5 changes under vehicular fleet growth scenarios in Brazil. Our results show an increase in PM_2.5 concentrations (up to 14%) aligned with an intensive increase (more than 70%) in the vehicular fleet between 2001 and 2010. During this period, we detected a similar pattern in more than 50% of urban spots in the South-East and other large urban centers in the South and Mid-West regions. Between 2011 and 2020, the stabilization or reduction of PM_2.5 is associated with a fleet growth smoothing combined with the continuous restrictions of PCVE. This work highlights the importance of planning and limiting fleet growth beyond vehicular technological improvement and emission factor restrictions.

Trends and drivers of PM_2.5 surface concentrations in Brazil.