library_construction_protocol: Samples no larger than 0.5cm2 were cut from each of the 5 locations of lung (trachea, bronchi at the 2nd/3rd generation, bronchi at the 4th generation, upper left lobe parenchyma and lower left lobe parenchyma) and additional small airway. Majority of the parenchyma was removed from the airway tissues, embedded in OCT and flash frozen in dry-ice cooled isopentane at -55°C. Haematoxylin and eosin staining was used to determine the morphology of tissue blocks, in order to choose those to proceed to Visium. Ten micron sections were then cut from the blocks onto Visium slides (10X Genomics) and processed according to the manufacturer's protocol. Nucleic acid was extracted according to the standard protocol of the Spatial 3' v1 protocol Tissue sections were loaded onto Visium chips according to the standard protocol of the Spatial 3' v1 protocol. Dual-indexed libraries were prepared, pooled at 2.25nM and sequenced.