Air Quality as a Technical and Political Issue for Sydney's Major Tunnels
Sydney has three major road tunnels constructed and operating this decade: the M5 East Tunnel, the Cross City Tunnel and the Lane Cove Tunnel. Each has had a difficult history:
* the M5 East Tunnel design was a major environmental problem, and subsequent operation has proven that the expected air quality issues were even worse than predicted; use of portal emissions and a recently announced $50M trial of in-stack filtration have both generated major controversy in the community.
* the Cross City Tunnel design was far better, but the environmental impact assessment was based on inappropriate or incorrect data. Only the existence of a toll and a much-below forecast usage has suppressed possible issues in the environs of Darling Harbour. Even so, use of portal emissions as a management device is a very controversial approach.
* the Lane Cove Tunnel will have been operating for almost a year by the time of this Conference. The environmental impact assessment suggests that there will be no significant air quality issues. However traffic congestion at the western end was predicted to give marginal air quality -- changes to the traffic management on surface roads may have created new issues.
Having had a long involvement with air quality issues for each of these Sydney tunnels, and having given evidence to four related Parliamentary Inquiries, the author is well equipped to discuss these issues.