This analysis examines the environmental risks of the commercialization of diesel passenger cars in Brazil, including a potential increase in NOX and PM2.5 emissions, both of which contribute to poor air quality and negatively impact human health, as well as greenhouse gases and other species that contribute to climate change. The analysis concludes that, given current regulatory standards, the wide commercialization of diesel cars would significantly increase NOX and PM2.5 emissions, contributing to poor air quality and adding 150,000 premature deaths through 2050. Even a moderate rate of dieselization, with diesel vehicles representing about 15% of light-duty vehicle sales after 2030, could result in as many as 32,000 additional premature deaths through 2050. Furthermore, this analysis shows that the commercialization of diesel cars also would result in increased climate impacts due to additional emissions of carbon dioxide and black carbon.