Air pollution(5) Particulate matter(5) mechanism(3) co-expressed(3) fibroblasts(3) TMPRSS2(3) expression level(3) lung(3) COVID-19 disease severity(3) angiotensin-converting enzyme 2(3) murine(3) pathway(3) caused(3) Bleomycin(3) expression(3) prevented(3) Reparixin(3) Treatment(3) lung alveolar(3) supplementary material(3) severity(3) poor prognosis(3) animal model(3) alveolar cells(3) Protein(3) Result(3) Deletion(3) transmembrane serine protease 2(3) suggested(3) Angiotensin-converting enzyme(3)