Air Quality Graphs for Melbourne

The data used to construct the two EPA graphs below have been obtained from the Victorian Environmental Protection Authority (EPA)  library and derive from the EPA's  Port Phillip Monitoring Network covering Melbourne and Geelong.

Visibility data for the graphs at the bottom of  the page comes from the Bureau of Meteorology (BoM), Melbourne.

Since 1996, air monitoring data for each year are reported separately but prior to that reporting periods and reported parameters vary.   Data for 1998 are posted on the EPA web site.   Monitoring for multiple pollutants is reported from about 1974 but Smoke and Dustfall numbers were found dating from 1964. The data graphed below is generally that which forms the most complete time series from stations centered on Melbourne and no more than 15 kms from the CBD.    The whole point of this exercise was to study data from the most heavily built up areas of Melbourne where traffic densities will be at a maximum.     As is obvious from the broken nature of the time series stations often ceased monitoring certain parameters or started new ones or closed altogether.   The best stations for longer runs of data are Alphington and  Footscray.  CBD data have been collected at three main monitoring locations, Parliament, Museum and latterly RMIT but there are many breaks.

The first graph is for the Airborne Particle Index (API)  post 1974 and the older Smoke and Dustfall numbers from 1964.  Round numbers were chosen to scale the 1964-1974 data so that the traces fitted sensibly into the rest of the graph.  The EPA web site has  information about the monitoring processes and technical issues relating to the various polluting species.  For the colour schemes I have tried to use reds & oranges - yellows for the 8 or 24  hour data and  purple through blues & greens  for the 1 hour data.   The longer the period reported for the maximum peaks, the values tend to be lower.

The following graph showing carbon monoxide levels is fairly typical of  graphs that could be shown for nitrogen dioxide, sulphur dioxide, ozone  and lead.

As with most environmental data collected over long time periods, early outlier values as in the API graph could be treated with some suspicion.  In a few early years there was a small overlap in reporting periods and where data did not agree I have entered the later numbers assuming that the later report writer would have had good reasons for departing from the earlier numbers.  Apart from that small overlap all data is shown here as reported.

The thrid graph shows the constant improvements in Melbourne annual 1 hour max ozone from 1974 to 2000. Natural levels will prevent much improvement from here.

What does this 35 year history of air quality tell us ?
For years we have lived with media / green / planning  dogmas that  automobile is a threat to our urban quality of life through the air pollution caused primarily by vehicle exhaust emissions.   It looks clear from these data that the steady improvements in car engine efficiency over the decades plus the introduction of exhaust catalytic converters in the mid-1980's has all been stunningly successful in reducing harmful  fractions in our urban atmosphere.  All the more so considering that these air quality improvements have been made against a background of increasing numbers of cars on our roads and increasing kilometres travelled.

Posted 8, September, 2000
Melbourne Visibility Data     In an attempt to extend measurements of Melbourne air quality further back into the 20th century, monthly average visibilities in kms for Melbourne have been plotted.   The steep increase in visibility over 45 years reflects improving air quality, mainly reduction in winter smogs and  on an annual average basis we are seeing about 8 km further these days than  in 1955.    This graph takes us back to the days of  extensive coal burning in Melbourne,  not to mention  motor vehicles that emitted dirtier exhaust gases.  The spikes in the graph probably have meteorological causes and if any plausible reasons come to hand they can be posted.

This improvement in visibility is mainly in cool  months,  to see graph of monthly increase trends clik here.

It is interesting to visit the CSIRO web pages and read  the doom and gloom about our air quality.  The Victorian  EPA site carries more air monitoring information but little about long term time series.  Taxpayers should consider whether we need so many of these expensive public serviice  atmospheric-meisters when air quality is improving.

Update 17, January, 2001.

The Victorian EPA website now has a page saying that Melbourne air quality is improving, will wonders never cease !!

Update 9, August, 2001

Graphic showing long term air quality history for London Thanks to Bjorn Lomborg

I think Melbourne would show a similar pattern with the worst polution maybe early 20C reflecting land clearing, coal burning etc.

You read it first here.

Page first posted 2, June, 2000,  updated September and  Jan., 2001

© Warwick Hughes, 2000

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