Where Clean Air Is Measured

The Kennaook / Cape Grim baseline air pollution station in northwestern Tasmania samples Southern Ocean air when winds arrive from the appropriate direction. Australia’s Bureau of Meteorology and CSIRO describe it as some of the cleanest air available for measurement—a characterization of a particular baseline air stream, not all of Tasmania. Country rankings such as Switzerland or Finland depend on year, pollutant, and monitoring coverage. [1–3]