AEC1, AEC2 alveolar epithelial cell 1 and 2 ARDS acute respiratory distress syndrome ASM airway smooth muscle AT1, AT2 alveolar type 1, alveolar type 2 BADJ bronchoalveolar duct junction BASC bronchoalveolar stem cell BMP bone morphogenetic protein BPD bronchopulmonary dysplasia CF cystic fibrosis CFTR cystic fibrosis transmembrane conductance regulator CGRP calcitonin gene-related peptide COVID-19 coronavirus disease 2019 ECM extracellular matrix EGF epidermal growth factor FACS fluorescence-activated cell sorting FGF fibroblast growth factor HGF hepatocyte growth factor HSC haematopoietic stem cell IL interleukin IPF idiopathic pulmonary fibrosis iPSC induced pluripotent stem cell LPS lipopolysaccharide MSC mesenchymal stromal cell NEB neuroepithelial body NGFR nerve growth factor receptor PDGFR platelet-derived growth factor receptor PNEC pulmonary neuroendocrine cell RSV respiratory syncytial virus SARS-CoV-2 severe acute respiratory syndrome coronavirus 2 scRNA-seq single-cell RNA sequencing SDF stromal cell-derived factor SMG submucosal gland TASC type 2-associated stromal cell TGF transforming growth factor TNF tumour necrosis factor VEGF vascular endothelial growth factor Throughout the Monograph the term “bronchus” refers to an airway with cartilage support, while a “bronchiole” is a smaller diameter airway, without cartilage support. List of abbreviations