Particles are classified by their size with PM10 referring to inhalable particles smaller than 10 microns (μm) in diameter. Of the inhalable particles, those smaller than 2.5 microns (PM2.5) can penetrate more deeply into the respiratory system and therefore pose the greatest risk to health (see diagram of particle sizes).
Benchmarking & Resources has more information on the guidelines and standards used for the following summary tabs.
The map shows annual average PM10 (μg/m3) measured at core monitoring sites across the region. Results are shown as a percentage of the national guideline which is an annual average of 20 μg/m3. The regional target is 13 μg/m3 or lower which is based on air quality being maintained at the ‘acceptable’ or better category which corresponds to no more than 66% of the national guideline (green to dark blue).
The table also shows the annual summary for PM10 reported as a 24-hour average from core monitoring sites across the region. The national standard allows one high pollution day per year which is a 24-hour average above 50 μg/m3 (or the 2nd highest 24-hour average to be below 50 μg/m3).The regional target is a maximum 24-hour average of 33 μg/m3.