This study was designed to (1) confirm the effects of DE (DEP: 1 mg/m3, which is similar to the concentrations that are inhaled in urban environments with serious air pollution) in an experimental model of BLM-induced lung injury and fibrosis; and (2) to identify the molecular mechanisms involved in these effects using wild-type mice (Nrf2+/+) and Nrf2-knockout mice (Nrf2−/−). This evidence concerns the gene NFE2L2 and fibrosis.