Pollution levels in Portsmouth continued to rise during the first of the clean air zone operation. This is the second year in a row that NO2 levels have increased, although the recent increase was small. A similar pattern is seen in both long term (10 years) monitoring sites and a broader set of locations with 3 years of monitoring data. These figures are taken from the city council’s own data.
Portsmouth had a class B CAZ introduced in 29th Nov 2021. The latest air quality report covers 2022 which is the first full calendar year that the CAZ has been in operation. We should expect to see most of the impact of the CAZ fairly quickly after its introduction, based on the experience of other cities.
As can be seen in the above graph, the average NO2 level in the city has risen for the last two years. The government is keen to emphasize the 5 year trend remains downward. The sites currently over the 40 ug/m3 legal annual limit in 2022 are:
- Alfred Road, 48.54 μg/m3 (AR-Col 9) by the Catholic Cathedral.
- Alfred Road, 45.89 μg/m3 (AR-Col12) by the Catholic Cathedral. This has almost doubled in the 2020 to 2022 period!
- Hope Street, 44.88 μg/m3 (HR-opp-Column4, site 120), road by The Cascades car park.
- Market Way, 48.47 μg/m3 (MW-OppStABS, site 145), behind the former Commercial Road Sainsburys. The pollution level here has more than doubled from 2020 to 2022!
- Kingston Road, 40 μg/m3 (KR-Col4), by the New Road junction. (An exceedance depending on your interpretation of the legislation. DEFRA are apparently using 40.5 μg/m3 as the limit.) This has almost doubled in the 2020 to 2022 period!
So not only has the CAZ focused on only some of the problem areas by ignoring London Road/Kingston Road, the tread for the last 2 years is actually for an overall worsening air quality! The worsening has been particularly bad along the Alfred Road/Hope Street/Market Way route into the city. The annual report suggests the slower renewal of vehicles during the COVID pandemic might be part of the problem.
Other locations of concern:
- 152 36.41 ug/m3 Column 171 Southampton Road (SR-Col171), near QA hospital junction.
- 273 37.7 ug/m3 Old London Road by Protyre
- 162 36.98 ug/m3 51 Eastern Road (ER-51) by Farlington A27 roundabout
- 163 36.67 ug/m3 52 Eastern Road (ER-52) by Farlington A27 roundabout
- 192 37.3 ug/m3 58 Kingston Road, Shirin Kebab
Since 2010, the council has had a legal obligation to bring down pollution levels as quickly as possible. This is on top of the public health need to make the air we breathe safer. However, the actions the council can take are down to central government funding and rules. According to the latest figures, the current plan including the clean air zone has failed. Despite this, there has been no public acknowledgement of this failure or an updated plan that actually addresses the air quality problem. Informally, I have been told that discussions are happening within the council on air quality, probably in collaboration with DEFRA. But I am concerned that this lack of transparency, combined with the track record of failure will lead to yet another unrealistic and illegal plan.
The 2022 NO2 pollution levels look like this:
Minor variations in NO2 levels are caused by changes in weather patterns. I suspect that the slight deterioration in 2022 is within this range, so it is plausible it is due to the weather. However, I would also expect a CAZ to make a significant difference, much greater than the effect of the weather. Instead of a downward short term drop, we are seeing an increase in pollution!
Key quotes from the draft report:
In the long-term, NO2 Annual Mean trend for the last five years (2018-2022) exhibited downward trend at 119 out of 155 locations (76.77%), in the meantime, NO2 Annual Mean trend exhibited upward trend at 36 out of 155 locations (23.23%) for the same period.
Why are we using a 5 year trend? According to the law, air quality targets must be met “as soon as possible” which in this context means within 2 years (that is about how long a CAZ takes to implement which was though of as a “quick” intervention). A 5 year trend also allows the government to rest on their (rather meager) laurels.
Delivery of a Charging Clean Air Zone was forecast to take 12–18 months. As this was Central Government’s preferred tool for bringing down emissions to within legal limits in the shortest possible time, any alternative suggestion would need to achieve the same reduction in emissions in a similar time frame. Therefore, any options which would take more than 24 months were assumed to have failed in the objective to reduce emissions to within legal limits in the shortest possible time.
This is the criteria the government is using for assessing the success of clean air zone, so we can see they have failed even by their own standards.
After extensive studies and numerical modelling, looking at both charging and non-charging options, it was identified that a Class B+ CAZ was needed to bring levels of pollutants down to within legal limits in the shortest possible time … The modelling forecast that this option would be effective at reducing emissions to within legal limits in the shortest possible time. There was therefore no legal need to introduce a CAZ C or D which could charge vans and cars.
The language of this section is misleading because we know now that a class B+ CAZ was insufficient. Therefore, the government probably had a legal obligation to introduce a stricter CAZ, but they failed to do so.
An important implication of the pandemic is the disruption that it was caused to the automobile market. In 2020, new car sales were down to their lowest level since 1992, and the number of newly licensed Heavy Goods Vehicles nationally was at its lowest level since 2014. With the difficulties in obtaining a new vehicle, this has been a boost to the second-hand market. From an air quality perspective, this is problematic as the newer vehicles are significantly less polluting than older vehicles. As a result, the improvement in per vehicle emissions has been less than the improvement that would have occurred without COVID-19 (as without the pandemic a greater number of older vehicles would have been replaced by new cars).
COVID is probably a factor in air quality and the composition of vehicle fleets. However, it doesn’t explain how things have deteriorated in certain hot spots.
Air pollution is the largest environmental risk to public health in the UK and it is known to have disproportionate effects on vulnerable groups. Air quality disproportionately affects the very old, the very young, and those with chronic conditions. It also has greater impact on those who live, work, or go to school in more deprived areas.
We must keep in mind the reasons for fixing air quality and the urgency of the task.
NO2 Annual Mean increased between 2021 and 2022 at 113 out of 227 locations (48.78%) and decreased at the remaining 114 (55.22%).
The report doesn’t state that the increase in pollution in the former is greater than the decrease in the latter. I guess the annual status report doesn’t want to produce a single figure for the entire city because it is arguably an over-generalization but at the same time it makes the report hard to understand.
PS I have created an FOI request for the 2023 data.