This site is one of four locations where Hornwright Industrial set up air purifiers. In reality, they were not used to clean the air but instead were modified to serve as a tool to convert aerosolized minerals back into a solid form.
Found north-west of the town of Lewisburg, this site has a small stone building with a large toolbox and a duffle bag outside next to a ruined car. Inside, there are more containers to be looted alongside a tinker's workbench, and some junk items on the metal shelves. The road to the southeast leads to the air purifier itself, which has more containers and various alcoholic drinks within the fenced area.
The Hornwright air purifier site #02 appears only in Fallout 76.