This bulletin is updated hourly with information calculated on data readings averaged over 8 hours for carbon monoxide, 24 hours for PM2.5 and 1 hour for PM10, ozone, nitrogen dioxide, sulfur dioxide and visibility reduction. Detailed information on the calculation of the index is available below.
Update 27 March 2015: Interim changes to our air network, mainly in metropolitan Melbourne, started on 27 February 2015. A number of instruments across the network will go offline for a short time, which will be noticeable on EPA’s website. Some of these changes will result in stations showing ‘N/A’ in the summary section – these changes will be noticeable for Point Cook from 26 March and Boxhill from 30 March. The instruments coming offline are used to monitor seasonal pollution issues such as ozone, which is mainly detected over summer. Across the network, we will continue to monitor for smoke from bushfires.
Update 28 February 2015: EPA has changed the way some of our data (including CO and SO2) is displayed in the air quality table. It is possible for CO concentrations to be reported by our equipment as a negative. To avoid any confusion, EPA is now rounding all readings back to 0. The raw data in our systems will remain as originally collected.
Data for a given hour are available at 30 minutes after the following hour. For example, data for the period from 9 am to 10 am is available at 10.30 am. See the Q&A below for more information about station summaries, ‘not available’ and ‘offline’ reports.