Below is a picture of the Arncliffe tunnel and smokestack situation. To avoid issues with WestConnex copyright, I drew it with Microsoft Paint onto a Google Maps screenshot. For the original WestConnex map, go to https://www.westconnex.com.au/map.
In Arncliffe, the smokestack will be 35 meters high.
The land rises toward the west and that is probably where at least one of the monitoring stations should go.
I had help from the community in compiling the options.
The site below is about the highest outside the school. I put it forward as a suggestion at the October 17 meeting.
Below is a picture of the intersection between the Princes Highway and Wickham Street. It is on the same hill as Arncliffe Public School, a bit closer to the smokestack but a little bit less elevated. Being at the intersection of two busy roads, this location would have some existing pollution. This would increase the probability of pollution target exceedances. Some vegetation might have to go to make way for the monitoring station. It was suggested by another member of the community and I put it forward at the October 17 meeting.
Between Marsh Street and the Cooks River is a cluster of high rise buildings, quite close to the smokestack, of which the tallest is 16 storeys and must be well over 40 meters high. That building is on the left in the picture below. That building, and probably some of the others as well, is taller than the smokestack which will only be 35 meters high. Even though the exhaust plume from the stack will rise, I imagine that on the edges, some of it will shear off and go wherever the wind takes it.
I am convinced that the residents near the top of those buildings will experience the greatest increases in air pollution. However, being higher up, they will have less pollution from street level sources. Whether that will bring their total above the targets, I am not able to say.
The WestConnex funded monitoring stations are to be at ground level, according to the approval conditions. So, I don't expect that WestConnex will fund a monitoring station on top of any high rise building, even if access and power can be negotiated. However, neither the approval conditons nor the national standard on which the approval conditions are based say that the air quality targets only apply at ground level. It may be an option for the residents to fund their own expert advice and, depending on what the experts say, air quality monitoring.