Portsmouth City Council are going to vote on the following motion on Monday 9th Sept:

Approves the proposed preferred package as set out in paragraph 5.12 as the preferred option to be taken forward to outline business case development; that is a Class B CAZ is combined with a number of non-charging measures to ensure that compliance is achieved within the shortest possible time i.e by 2022.

A class B CAZ covers buses, coaches, taxis, private hire vehicles and heavy goods vehicles. I doubt that this will be sufficient based on other cities that have introduced similar schemes. For example, the London Low Emission Zone had minimal impact on NO2 levels (before it was upgraded to a ULEZ). Cities in the Netherlands with a LEZ have also seen minimal impact. Only when light goods vehicles and cars are included in the CAZ, such as schemes introduced in Germany, do we see significant changes in NO2 levels.

PCC says they have selected a class B CAZ based on modelling. Given case study evidence suggests this will have minimal impact, I am immediately suspicious of their model. They have a track record of predicting drops in NO2 levels that fail to materialize. For example, in their 2010 plan, they state they will reach legal levels by 2012-2016:

5.9. What is the likely date for compliance with the NAQO? With no additional remedial measures being implemented, an estimate of the likely date for compliance with the NAQO has been made. This estimate has been calculated using the approach described in LAQM TG09. The results of this approach are listed in Table 6.

Table 4: Estimated Year of Compliance with NAQO

AQMA Year of Compliance – Annual Mean NO2 Objective
AQMA6 2016
AQMA11 2012

In reality, NO2 levels have been roughly unchanged. My suspicion is they are using unrealistic traffic projections. More traffic means more pollution. Why should we trust their modelling if they have been wrong before? Another factor is that the consultants hired to do the analysis are only likely to be rehired by the council if they provide a report that says what the council wants to hear, which might bias their thinking.

I downloaded and plotted the local authority traffic levels based on data from the department of transport.

Over this 23 year period, Portsmouth seems to have had a 7% increase in motor traffic. That is less than I would have expected. This is about 0.4% per year. Reports by PCC used in road planning have used 4.1% per annum. Their air quality reports have used 0.5%, which is contradictory but perhaps more reasonable. Perhaps the growth in traffic they expect is highly localized? I need to think about this! Their model prediction of 2022 still doesn’t match the case study evidence.

It is not entirely clear that the council intends to introduce a charging CAZ based on their reports. I suspect this is just a lack of clarity in the language.

The council should be benchmarking various options against both a charging CAZ, as well as option of doing nothing. This allows us to check if their model is realistic since we want to know the impact of each measure separately.

The report is also very focused on measures that will deliver results in the short term. While this is important, PCC should also be looking at continuous improvement and to go beyond the legal standards. However, PCC’s track record of failing to do even the legal minimum shows their priorities do not include public health.

Whilst none of these measures alone was considered sufficient to bring forward compliance, implementation of all three measures in combination was predicted to bring forward compliance from 2020 to 2019 for A3 Mile End Road and from 2023 to 2022 for A3 Alfred Road.

Most of the measures proposed by PCC are difficult to quantify. However, I hope that they attempted to do so using realistic estimates.

Work is continuing to develop Portsmouth’s Air Quality Local Plan for submission to JAQU by 31st October 2019.

This should be circulated to the public as well, since they are the ones affected by it. Hopefully we don’t need to force PCC’s hand unlike their draft plan which they refused to circulate but did after a freedom of information request was sent.

The air quality situation being handled as an inconvenience by PCC rather than a public health crisis reminds me of the last scene in Chernobyl.

To be a scientist is to be naive. We are so focused on our search for truth, we fail to consider how few actually want us to find it. But it is always there; whether we see it or not, whether we choose to or not. The truth doesn’t care about our needs or wants, or governments, or ideologies, or our religions. It will lie in wait for all time and … this, at last, is the gift of Chernobyl.

Also, see the earlier post on legal concerns. Coverage in the local paper.