The COPD features observed in these mice are significant increases in the chronic airway and lung cellular and cytokine/chemokine (increased TNF‐α, CXCL2, IL‐1B, keratinocytes‐derived chemokine (KC)/murine equivalent of human IL‐8) inflammation, airway remodeling and fibrosis, emphysema and impaired lung function and gas exchange compared to control mice exposed to normal air.22, 34. This evidence concerns the gene TNF and pulmonary emphysema.