Highs and lows of the Clean Air Zone

Air quality in Bath is improving though – it seems – road works like Cleveland Bridge – have upped pollution levels elsewhere.

New figures published today show the city’s Clean Air Zone (CAZ) is continuing to improve air quality in the city and that the number of chargeable vehicles is decreasing.

The data shows an average 14% decrease in nitrogen dioxide (NO2) levels within the CAZ in the last quarter compared with the same period in 2019, with similar levels shown in urban areas outside the zone’s boundary.

Air quality has also improved at key locations including Gay Street and Upper Bristol Road.

Levels of NO2 at Wells Road, Victoria Buildings, Broad Street, and Chapel Row have increased but this is expected to stabilise once temporary works impacting traffic have been completed, including the Cleveland Bridge renovation project.

The figures have been published as part of the second quarterly report to monitor the performance of the Clean Air Zone that is going before Bath & North East Somerset Council’s cabinet on December 16. It analyses air quality and traffic data gathered for the period July to September 2020.

The data also indicates that the CAZ is having the intended effect of improving fleet compliance and changing behaviours.

More than 90% of HGVs, coaches, buses and taxis entering the zone are now compliant. Van compliance rates have also seen an upturn and are now approaching 80%.

The report also states that of the 2,500 vehicles assessed under the council’s financial assistance scheme to replace non-compliant polluting vehicles, 1,495 were found to be eligible. 591 vehicles have already been replaced with hundreds more expected to be upgraded in the coming months.

Councillor Sarah Warren, Deputy Leader and cabinet member for Climate and Sustainable Travel, said: “Once again, this quarterly update provides encouraging data that air quality is improving and pollution is reducing in the city. We have updated the method by which we make some of the comparisons with the results from previous quarters, making these figures even more robust. It’s fantastic news that the CAZ is having the intended effect of tackling the air pollution that can significantly damage people’s health.

“However, the impact of temporary works in the city on traffic flow – including Cleveland Bridge – mean that we cannot draw firm conclusions on data for the locations showing an increase in NO2. We need to take a long-term view as we expect to see an improvement in air quality in these areas in the coming months, which we’ll draw further conclusions about in forthcoming reports.

“Our target is to reduce annual average concentrations of NO2 to below 40 μg/m3 (micrograms per cubic meter of air) at every location where we measure NO2 in Bath, as soon as possible and by the end of 2021 at the latest. Obviously, we will not know whether we’ve achieved this until our annual report released in the spring of next year.

Our quarterly reports suggest that there are still a few areas that are a cause for concern, including around Cleveland Place, so we ask that everyone pulls together to limit their use of vehicles where viable alternatives exist, such as using park and rides, walking, using an electric bike or scooter or car-sharing.”

“We are also working with the Joint Air Quality Unit (JAQU) on how we demonstrate that we have achieved compliance with air quality limits going forward.”

Bath’s CAZ was launched on 15 March 2021 to urgently tackle harmful levels of air pollution caused by the most polluting taxis, vans, buses and larger commercial vehicles regularly driving in the city.

It was the first to be launched outside London and works to reduce pollution in Bath by levying a £9 or £100 a day charge on anyone driving a chargeable higher emission vehicle in the zone. This excludes private cars and motorcycles which are not charged. 

The charges are designed to deter higher polluting vehicles from entering the zone, while also speeding up the natural replacement rate of polluting vehicles in exchange for cleaner ones. Any revenue over and above the operating cost will be spent on providing sustainable transport.

You can read the report going before cabinet on December 16 at 11.00am here.

Watch the webcast of the cabinet meeting live or view it later on the council’s YouTube channel.

1 Comment

  1. The data https://democracy.bathnes.gov.uk/documents/s69557/Appendix%203%20Air%20Quality%20data.pdf shows how far off we are with getting to legal limits of NOx.

    It should be noted that using the 2017 CAZ ANPR data set Bath Hacked ran a council sponsored “hackathon” where analysis showed that 20% of NOx was attributed to HGVs and buses, and 40% each to LCVs (Vans) and cars.

    Given that HGVs & Vans are being charged and we’ve seen a major shift to compliance, the only politically hard group to tackle now is older cars. Given that some of the illegal sites are on routes where HGVs are banned (7.5t weight limit) this makes sense and we should see a CAZ D come into play next year.

    Hopefully this means we can close three sides of Queen Square!

    Significantly the World Health Organisation has now stated 20 μg/m3 NOx is the new safe level. So I suspect once that rolls in we will see a shift to charging all fossil fuel vehicles accelerating the shift to electric vehicles within the next 5 years.

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