Bath’s Clean Air Zone continues to be effective in improving air quality

The 2022 Annual CAZ report published by Bath & North East Somerset Council reveals that compared with 2019, there has been a 26% reduction in annual mean NO2 within the zone, representing an average reduction of 8.5 microgram/m³.

A Class C Clean Air Zone was implemented in March 2021, whereby all higher emission vehicles except private cars and motorbikes were charged and some additional traffic management was introduced. A consultation on the CAZ in 2018/9 showed the overwhelming opinion was that a class C would strike a better balance between tackling pollution and protecting central businesses and vulnerable residents that might be disproportionally affected by charging higher emission cars.

The council launched a £9.4m financial assistance scheme to help local businesses and individuals replace or upgrade polluting vehicles with compliant ones, an offer which was taken up by more than 1,500 people. 

2019 is used as the baseline year for analysis as it is the most recent year with pre-CAZ data that has not been impacted by the Covid-19 pandemic.

The figures in the recently published Annual CAZ report also show that in the urban area outside the zone, there has been a 27% reduction in annual mean NO2 concentrations (an average reduction of 7.1 microgram/m3) with only one site exceeding the legal limit of 40 microgramg/m³. Ten sites had exceeded the limit  in 2019.

The figures also indicate an additional reduction of 6% in annual mean NO2 concentrations in 2022 compared with 2021, as well as a reduction of 7% within the CAZ boundary.

The report shows that compliance is increasing, with 71% fewer polluting vehicles driving in the zone by the end of December 2022 – an average of 497 vehicles per day – compared with an average of 1,742 vehicles in the first week the CAZ launched in March 2021.

Councillor Sarah Warren, deputy Leader and cabinet member for Climate Emergency and Sustainable Travel, said: ‘It’s heartening to see the clear indications in this report that the clean air zone is working to improve air quality across the area, not just within the zone.

‘The upturn in compliance demonstrates support from the public which should be applauded, but we recognise that there is still more to do to drive down pollution at all locations in Bath. Looking ahead, we’ll pay particular attention to sites that continue to exceed legal limits and find specific solutions to combat this.

‘We will also continue to promote sustainable travel alternatives to the car which will increasingly enable people to walk, cycle or wheel for healthier short journeys around the city, reducing both pollution and carbon emissions from transport.’