It is unlikely that a class B Clean Air Zone will bring air pollution within legal limits in the short term. Cars are the main source of pollution, which is ignored under this CAZ plan, so it misses the most obvious opportunity to address the problem. [Thinking about it, I’m not sure that is true.] No other cities have seen big changes in NO2 after introducing a class B CAZ. Portsmouth also has a track record of over optimistic air quality predictions. For example, in the 2010 plan, PCC states they will reach legal levels by 2012-2016. This many be due to unrealistic assumptions, bad traffic data or a mistake in the analysis. Why should we trust the latest modeling when the older predictions were very wrong? The proposed city centre road scheme will ruin any chance of legal compliance. Is the traffic from this and other future developments included in the air quality model? Will the council commit to stop any plan that violates air quality limits? Given the experience of similar cities, CAZ Class D should be modelled and planned, as well as a “do nothing” option, and the option of a class D CAZ with a ban on older diesel vehicles. This is the only way we can be reasonably certain to meet legal requirements and provides a stepping stone towards PCC’s commitment to go net zero carbon by 2030.
There is an issue with the legality of the council’s plans. The council report states that “a balance [needs] to be struck between achieving compliance with legal requirements to reduce harm to people’s health and the impact that such measures could have on the local economy and resident’s livelihoods.” End quote. The High Court rejected that argument saying cost is not to be considered in planning, only efficacy is to be considered. Quote: “I reject any suggestion that the state can have any regard to cost in fixing the target date for compliance or in determining the route by which the compliance can be achieved where one route produces results quicker than another. In those respects the determining consideration has to be the efficacy of the measure in question and not their cost.” End quote. The current air quality plans should be opposed until they meet legal standards.
Portsmouth lacks a safe cycling and pedestrian network, such as seen in Rotterdam and other cities. It is not clear that PCC is prioritizing active travel as a means to tackle air pollution. For instance, Portsmouth Cycle Forum recently objected to the proposed Seafront cycle route saying it was not safe. The proposed city centre road scheme is also overly focused on private vehicles and only does the bare minimum for active transport.
PCC’s plans only seem to extend to 2022. While achieving short term legal air pollution levels is important, it is also necessary to put in place a long term plan for continuous improvement of air quality. Council modelling seems to ignore the possibility of improvements to public transport, which should be a key part of an air quality strategy, to provide people with a practical alternative to car use. A credible air quality plan would have long term ambitious measures, as well as help for residents and businesses to adapt.