Overview of New M5 Air Quality Issues
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The New M5 (now renamed to M8) has been built with three unfiltered smokestacks.
The locations are as follows:
- Near the Kingsgrove portal, about half way between King Georges Road and Kingsgrove Road.
- In Arncliffe near Marsh Street
- At the St Peters interchange
According to the
Environmental Impact Statement, section 10.8.2, table 10.23, the height of the stacks
is 30 meters for Kingsgrove, 35 meters for Arncliffe and 20 meters for St Peters.
A committee, called the New M5 Air Quality Community Consultation Committee (now renamed to M8 Air Quality
Community Consultation Committee), has been established
to deal with air quality issues (I am a member, representing the Arncliffe community). We have been meeting
most quarters since September 2017.
Locations where air quality is be monitored
Air quality for the M8 is monitored and the first major task of the
committee was to contribute to the selections of locations for the air quality monitoring stations.
There are two monitoring stations per stack. Also one in the St George area, away from the stacks.
In addition, there will be a monitoring station in the general area near the M8 but not close
to any stack to measure background air quality.
Selecting good locations for the air quality monitoring stations for each stack is critical. If the stations
are in locations that are not nearly as much impacted as some of the locations that are not monitored, the
consequence is that air quality targets can be breached and we simply will not know and therefore no
remedial measures can be enforced on the road operators. Unfortunately, I have some bad news to report in
this regard, especially for Kingsgrove.
Early Results
For more information see Air Quality Monitoring for the M8 section.
Here is a quick summary based on results up to April 2021 and the results of the 2015/2016 monitoring
program (The results from the year before the M8 opened were rendered meaningless by construction which
also caused air pollution):
- Arncliffe appears to have benefitted from reduced road travel to and from the airport as
there is less air travel during the pandemic. Measured air quality has improved and improved
more than at the background location.
This is more significant than the M8 project.
- St Peters air quality got worse, even though air quality got better at the background location.
This may not all be due to the tunnel. There are also the interchange and all the widened roads
around it.
- For Kingsgrove we can't make any meaningful comparisons, because no monitoring station is in the
same location as in the 2015/2016 program. As a member of the committee I personally accept some
blame for that. We should have asked for one location to be reused, even though none of the
locations from the 2015/2016 program were very good. But the community reps, including myself, didn't
realise the implications of not reusing one. I apologise for that.
Note to future air quality committees: Unless you reuse from the pre-construction program the
background location and at least one location for each stack, you will not be able to make meaningful
before and after comparisons for all stacks.
Background Information
There was an air quality expert at the September 19 (2017) meeting who gave a whole lot on information and explanation.
This is some of what he said:
- Ground level emissions through the portals (tunnel entrances and exits) are not acceptable.
- The moving traffic will push the air along in the direction of travel. This process
will be assisted by fans within the tunnels. The ends of the tunnels are logical locations
for smokestacks, so that the dirty air can be sucked up through the stacks before leaving the tunnel
with the traffic.
- Because of the huge amount of air being blown out of the stacks, it will have quite a bit of momentum
and will continue to rise. He described the rate in terms of swimming pools per minute.
- The harmful health impact of very fine (fraction of a micron) particles is acknowledged.
- Small particles behave like gases and don't really settle.
- Emissions of particles from vehicles and nitrogen oxides has been falling and will continue to fall
because of improving vehicle technology. However particle emissions are not expected to fall to zero because some
particles come from tires and brake pads.
- If air quality monitoring shows that the modelling is wrong and air quality is worse then expected,
placing Westconnex in breach of consent conditions,
the potential is there for filtering to have to go in after all.
Air quality monitoring will be covered in a separate topic, because it such an important topic.
- He lives in St Peters, so he has a personal interest in air quality remaining acceptable.