Click a station for details
Good Fair Moderate Poor Very poor
Particles less than 2.5 µm (PM2.5) 0-10 10-20 20-25 25-50 50-800
Particles less than 10 µm (PM10) 0-20 20-35 35-50 50-100 100-1200
Nitrogen dioxide (NO2) 0-40 40-100 100-200 200-400 400-1000
Ozone (O3) 0-80 80-120 120-180 180-240 240-600
Sulphur dioxide (SO2) 0-100 100-200 200-350 350-500 500-1250
Index level (based on pollutant concentrations in µg/m3)