“…The greatest exposure route for ENMs is through inhalation, leading to concern that ENMs will cause or exacerbate respiratory diseases. Many previous studies have shown that ENMs cause chronic lung inflammation, pulmonary fibrosis, lung cancer, or exacerbation of allergic lung disease in experimental animals [ 56 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ]. Other studies using cultured human or rodent lung cells demonstrate that ENMs increase the production of pro-inflammatory or pro-fibrotic mediators [ 76 , 77 ].…”