Bristol’s Clean Air Zone is on the road to success, one year on

  • 1st December 2023

One year on from Bristol implementing the Clean Air Zone, the Joint Air Quality Unit (JAQU) has produced their first interim report on the zone.

Findings suggest that clean air is being delivered in Bristol, with data indicating that air quality in the city will not exceed the Government’s average annual legal limit this year.

Marvin Rees, Mayor of Bristol, said:

“The Clean Air Zone, mandated by national government, was never about generating income, it was about delivering cleaner air to secure a healthier future for Bristol. A year after the start of the Clean Air Zone, this report from the Joint Air Quality Unit demonstrates that we are on track.

“Thousands of people have taken up some of the £42m funding support we secured for Bristol, and 82% of cars are now compliant. Residents across our city have accessed 25,000 travel offers, including bus tickets, cycle training, bike loans, and car club vouchers. However, we still have a significant amount of financial support available for individuals and businesses, and so I encourage everyone to have a look and see if you’re eligible.”

Christina Gray, Director of Communities and Public Health, Bristol City Council said:

“These early results from Bristol’s Clean Air Zone are a positive indication that we are heading towards a healthier Bristol. Clean air is important in helping reduce the risk of respiratory issues and infections such as asthma, lung cancer, heart disease, and stroke. Air pollution can also contribute to other health issues like depression.

“Our children, grandchildren, and beyond will benefit from the cleaner air that we are all delivering through changing vehicle use and our active travel.”

How Bristol’s Clean Air Zone is being assessed

The Council monitors air pollution via diffusion tubes at just under 200 locations throughout the city, both inside and outside Bristol’s Clean Air Zone. A diffusion tube is a scientific device that samples the concentration of gases in the air. They are used to monitor average air pollution levels across Bristol. There are four different stages for the Government to determine if a Local Authority is achieving success.

  • State 1 – on track to achieve success
  • State 2 – has achieved success
  • State 3 – demonstrated to be maintaining success with measures
  • State 4 – likely to continue maintaining success in the absence of measures

Success is defined by national government and means that the measures put in place, for example Bristol’s Clean Air Zone, is having the desired effect and further air pollution will not exceed the annual average legal limit.

The purpose of this technical report from JAQU, known as a State 1 report, is to assess whether a Local Authority is on track to achieve success by the end of the calendar year. The report assesses Bristol’s air quality data from diffusion tubes and provides transport data analysis from the first six months of the 2023 calendar year. This data provides a representative average period for the in-year assessment.

Bristol’s data forecasts that the Clean Air Zone is having a positive impact on air quality. Data indicates that further NO2 concentrates will not exceed the Government’s average annual legal limit. This means that Bristol’s State 1 assessment is successful and JAQU recommend progressing to State 2.

The diffusion tubes must be analysed in a laboratory, which takes on average four to five weeks. Due to this processing time, a full 12-month report with operational data (air quality and financial) will be published as part of papers for January’s Cabinet meeting, alongside JAQU’s State 1 report.

You can visit the Bristol City Council website for more information about the zone, including a vehicle checker and boundary map to help you best plan your journeys: