How to use and read the graphs

  • Use the grey selection tool above to adjust the date range of the data set or hover over the chart and use your mouse wheel.
  • If you are having trouble viewing the entire graph, try decreasing or increasing the zoom level on your web browser.


  • PM2.5 = fine particles with a diameter of 2.5 microns (millionths of a metre)
  • PM10 = small particles with a diameter of 10 microns
  • O3 = ozone
  • NO2 = nitrogen dioxide
  • SO2 = sulphur dioxide
  • TRS = total reduced sulfur
  • ppb = parts per billion
  • ppm = parts per million
  • µg/m3 = micrograms per cubic metre
  • N/A = Readings are monitored but are not available at this time.