Report says city centre pollution levels ‘down by almost 40 per cent’

Improvement in air quality has been put down to the Clean Air Zone’s launch in 2021, an area covering inside the city’s A4540 Middleway Ring Road.

Last year’s reduction in nitrogen dioxide was compared with 2016 as that was the year the original CAZ modelling was introduced.

The council report, issued today, October 6, also revealed pollution in 2022 was down by an average of 17 per cent when compared to pre-pandemic results in 2019.

Other key findings include a reduction in the number of ‘non-compliant’ vehicles entering the zone – down from 15.2 per cent in June 2021 to six per cent in June 2023.

This despite the average number of unique vehicles entering each day increasing from 98,112 in the first year of operation, to 102,392 in the second year.

The authority said two areas within the zone, Moor Street interchange and St Chads Queensway, are facing ‘ongoing exceedances of the legal limit for nitrogen dioxide'.

It added: “While there are ongoing exceedances in these areas, the levels of nitrogen dioxide are reducing.”

In addition to those areas there are three locations on the A4540 Middleway with levels of nitrogen dioxide that are currently above the legal limit.

Work to better understand the sources of the ongoing exceedances has already taken place.

Councillor Liz Clements, cabinet member for transport welcomed the report’s findings but said there is “more work to do”.

She said: “Tackling the health inequalities caused by poor air quality is vitally important, so it’s encouraging to see that the levels of nitrogen dioxide in the city centre are continuing to reduce.

“I want to thank everyone in the city who has helped to make this change possible. However, there is more work to do. There are now far fewer of the most polluting vehicles entering the city centre.

“But we have to find ways to support and encourage more people to leave their vehicle at home more often.

"An overall reduction in the volume of vehicles driving through the city centre will help improve air quality, reduce carbon emissions and create a more enjoyable environment for everyone.”

The CAZ was launched as part of the council’s plan to tackle the risk to public health caused by poor air quality.

The scheme is designed to specifically address the air pollutant nitrogen dioxide and to do so in the shortest possible time.

The data issued today is the second progress report on the CAZ and makes use of the data from the Annual Air Quality Status Report for 2022 and the network of Automatic Number Plate Recognition (ANPR) cameras used to support the operation of the Clean Air Zone.

A council spokesperson said: “A common theme emerging from the work is that while the percentage of compliant vehicles moving through these areas is broadly similar to all vehicles entering the zone, the combination of vehicle volume and other environmental factors in each area could be slowing down the rate of improvement.

"Further work is required to better understand the scale of change required to achieve the desired reductions in nitrogen dioxide.”