❓ A WA parliamentary question seeks information on air quality monitoring and pollution control measures within the Northbridge Tunnel. The Minister provides details on monitored pollutants, permitted levels, actions taken when limits are exceeded, and filtration equipment used.
AnsweredQoN 2949Legislative Council
QuestionView source ↗
(1) Further to question No. 722 regarding the Northbridge Tunnel, will the Minister explain what pollutants are being monitored inside the tunnel and what air quality standards are required?
(2) What is the maximum permitted level of each of these monitored pollutants?
(3) What is the maximum measured level of each of these pollutants inside the Northbridge Tunnel?
(4) What action has, or will be, taken if these maxima are exceeded?
(5) What filtration equipment is used to filter the air in the tunnel and that discharged through the exhaust stacks?
(2) What is the maximum permitted level of each of these monitored pollutants?
(3) What is the maximum measured level of each of these pollutants inside the Northbridge Tunnel?
(4) What action has, or will be, taken if these maxima are exceeded?
(5) What filtration equipment is used to filter the air in the tunnel and that discharged through the exhaust stacks?
AnswerView source ↗
Answered
14 March 2006
Responded by
Parliamentary Secretary representing the Minister for Planning and Infrastructure
Response time
118 days
(2) The first alarm level for Carbon Monoxide is set at 100 PPM. The first alarm level for Nitrous Oxide is set at 6 PPM and for Visibility at 112% (3) Maximum levels have generally been in the order of about 20 PPM for the CO (and under 2 PPM for the NO.) On one exceptional occasion since the tunnel was opened the readings for CO reached 60 PPM during a major traffic incident involving the annual motorcycle charity run. (4) For poor visibility traffic speed is reduced, for high CO or NO a lane closure is put in place to reduce traffic (and emissions) and if the levels do not fall then that tunnel bore would be closed to traffic until they did. In five years of operation this has not been necessary. (5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
(3) Maximum levels have generally been in the order of about 20 PPM for the CO (and under 2 PPM for the NO.) On one exceptional occasion since the tunnel was opened the readings for CO reached 60 PPM during a major traffic incident involving the annual motorcycle charity run. (4) For poor visibility traffic speed is reduced, for high CO or NO a lane closure is put in place to reduce traffic (and emissions) and if the levels do not fall then that tunnel bore would be closed to traffic until they did. In five years of operation this has not been necessary. (5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
(4) For poor visibility traffic speed is reduced, for high CO or NO a lane closure is put in place to reduce traffic (and emissions) and if the levels do not fall then that tunnel bore would be closed to traffic until they did. In five years of operation this has not been necessary. (5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
(5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
(3) Maximum levels have generally been in the order of about 20 PPM for the CO (and under 2 PPM for the NO.) On one exceptional occasion since the tunnel was opened the readings for CO reached 60 PPM during a major traffic incident involving the annual motorcycle charity run. (4) For poor visibility traffic speed is reduced, for high CO or NO a lane closure is put in place to reduce traffic (and emissions) and if the levels do not fall then that tunnel bore would be closed to traffic until they did. In five years of operation this has not been necessary. (5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
(4) For poor visibility traffic speed is reduced, for high CO or NO a lane closure is put in place to reduce traffic (and emissions) and if the levels do not fall then that tunnel bore would be closed to traffic until they did. In five years of operation this has not been necessary. (5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
(5) There is sound "filtration" fitted to both sides of the exhaust fans located at the base of the exhaust stacks. The air discharged through the exhaust stacks is filtered and diluted by the velocity at which it is discharged into the upper atmosphere and the wind currents present at that altitude.
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