Airsheds

Part of speech: noun

Definitions

1. A defined geographic region where air quality is managed to prevent pollution
2. An area where atmospheric conditions are monitored to assess air quality impacts
3. A specific zone where emissions are regulated to maintain clean air standards

Etymology: "Airsheds" is the plural of "airshed," a term for a defined area whose air quality is managed together, much as a watershed is a region whose rainfall drains to a common river. The word is built from "air" and "shed," with "shed" in its older sense of a dividing ridge or the region drained on one side of it, and it was modelled directly on "watershed." Watershed itself began as a term for the line of high ground separating two river basins, so the newer word borrows that picture of a boundary that sorts whatever falls within it.