This chart compares annual average levels of PM2.5 during 2018 at NSW Office of Environment and Heritage (OEH) monitors in the Sydney basin with the levels at WestConnex monitors. Darker blue are Ecotech monitors, lighter blue are OEH monitors. 8 is 8 µg/m³, which is the national limit for annual average PM2.5. Everything above 8 µg/m³ is a national exceedance. Location names refer to the sites of monitors.