Birmingham’s Clean Air Zone (CAZ) has been less effective at reducing air pollution than was initially claimed, new research has revealed.
The CAZ was said to have reduced the levels of nitrogen dioxide gas (NO2) in the city centre by around 13%, yet a recent study by scientists at the University of Birmingham has found that the reduction in NO2 pollution was only of up to 7.3% – around half the estimated amount. The research called the findings ‘modest, but significant’ reductions.
The news comes as the ULEZ in London has doubled in size this week to cover every borough in the city, leaving thousands of drivers facing a daily charge of £12.50.
The CAZ in Birmingham works in a similar fashion to London’s ULEZ, charging motorists who own higher polluting vehicles when they enter the zone. It was introduced in June 2021 with the aim of reducing certain harmful emissions produced by older cars and lorries. However, the CAZ has no detectable impact on the air pollutant with the greatest health effects, PM2.5.
Professor Zongbo Shi, from the University of Birmingham, said: “PM2.5 at monitoring sites in Birmingham still regularly exceed WHO [World Health Organisation] air quality guideline levels, at which health impacts occur with significant health implications, including hundreds of premature deaths every year.”
A spokesperson for Birmingham City Council said: “What is clear from this modelling is that the introduction of the clean air zone led to an overall reduction in the levels of the air pollutant nitrogen dioxide. This modelling also supports our own analysis that the clean air zone has contributed to an overall reduction in the levels of nitrogen dioxide outside of the city centre.
“However, since the period covered by this modelling, the overall percentage of the most polluting vehicles entering the clean air zone has continued to reduce and we expect there to be further reductions in the levels of nitrogen dioxide.”