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A year on living with the Clean Air Zone


Written by Greg Fell, Director of Public Health, Sheffield City Council.

Today marks exactly one year on from when we first launched our Clean Air Zone (CAZ) in Sheffield.  

Whilst the introduction of the CAZ has required some adjustment for many of us, the evidence is clear, when it comes to air pollution, there is no safe limit and, with 1 in 20 deaths in Sheffield attributable to air pollution, we must all act to protect the health of ourselves, our loved ones, and the environment around us.  

A year on living with the CAZ and we are seeing the kind of positive results we were hoping for. The number of polluting vehicles within the CAZ boundary has seen a huge drop compared to the year before, two thirds of a reduction, or 64 per cent to be precise. Data also shows that the polluting traffic around the boundary has also dropped by 18 per cent – suggesting that more and more people are making the switch to cleaner vehicles(1).  

So, what does this mean for the health of local people who live, work and study in those poor air quality hotspots?  

Air quality impacts our health and can lead to life changing diseases. This assault on the health begins in the womb from the first few weeks of pregnancy and impacts the development of an unborn child(2).  

Long term improvements to air quality and a sustained reduction in exposure to harmful pollutants will reduce life threatening diseases - such as lung cancer, stroke, and asthma(3) - reduce pressure on health services and improve the health and livelihoods of future generations.

WATCH: Director of Public Health Greg Fell shares some words about the importance of better air quality on our health

We often get asked, where is the latest data proving that poor air quality causes deaths in Sheffield? The simple answer is, getting the data on how many people die as a result of breathing in poor air quality isn’t simple, I co-wrote an article last year explaining how we quantify the impacts of poor air quality and who is most likely to suffer as a result(4).

The published medical evidence on the impact pollutants have on our health is compelling and continues to mount. This was most helpfully summarised by the World Health Organisation in 2021(5), and in the England Chief Medical Officer 2022 report(6). 

The way we think about the impact of air quality needs to be considered. Just because we can’t see it or attribute it directly to cause of death or illness, it doesn’t mean that it’s not a very real threat. 

Take smoking for example. It wasn’t until the 1950’s that research was published proving that smoking cigarettes led to serious life-threatening illnesses and death(7). Prior to this, due to a mix of glamorising advertising campaigns and a lack of tangible research to suggest otherwise, the notion was disputed, with many actually believing that smoking was good for you!  

Today, with the appropriate awareness campaigns and government support, we as a society are well aware of the impacts of smoking on the health, as well as the equally negative impacts of passive smoking(8), hence why we are seeing a year-on-year decline in the number of smokers across the UK. We no longer see smoking in public buildings or in cars with children, and new laws are continually introduced to reduce accessibility and desirability of cigarettes.  

There are many who have estimated that the levels of air pollution in many cities is equivalent to smoking cigarettes(9). But even now, you will not see ‘smoking’ listed as a cause of death or illness. The same can be said for poor air quality.  

Just like the change in behaviour and awareness we are seeing towards smoking, Clean Air Zones across the UK and London’s ULEZ encourage us all to rethink the wider health implications of the way we travel and, with road transport responsible for 80 per cent of roadside NO2 pollution alone(10), we all have a responsibility to change.  

Let’s consider Amsterdam in the Netherlands, it wasn't always one of the most walking and bicycle friendly cities in the world. But, after decades of hard work, in the late 1970’s real change for cycling policies and pedestrian and bike friendly streets started to be introduced(11). 

When we look at the impact switching to cleaner and more active modes of travel has made in the Netherlands, the results speak for themselves. Cleaner and active modes of travel mean better air quality and improved health and wellbeing for the population(12). 

Closer to home, we are seeing real impact that the switch to walking and cycling can make. In London, cycling infrastructure, coupled with the ULEZ, is driving down air pollution and is allowing more and more Londoners to take up cycling. Latest figures show that weekday bike trips in London are up 20 to 25 per cent, when March 2020 is compared with October 2022, while there has been a 90 per cent increase in cycling at the weekend(13). 

In the city centre, we're working on transport schemes which will improve our infrastructure for walking, wheeling and cycling. With wider footways, new connected cycle routes and improved facilities for bus users, enabling more people to make car-free journeys(14) 

By providing more choice in how you travel, we hope to reduce people’s reliance on the car for shorter trips. This, in turn will reduce congestion, make public transport more reliable, and free up space on the road for people who need to travel by car. 

One great change we can all make to improve our own health and the health of others around us is to take more active travel journeys.  

Why not give it a try as we move into the warmer months? Switching even a single journey or part of a journey every week is a great start and will help improve cardiovascular health and overall fitness.  

Locally we also have some great cycling schemes to support people on their cycling journey, and through the Better Points app, you can even collect points by logging walking, cycling and public transport journeys, which can later be redeemed for high street awards or can be donated to charity(15).

So what next?

As the Clean Air Zone moves into its second year, its first full year, the data we receive on the how it is performing will be clearer and more indicative of its impact. In coming weeks, we expect to receive our one-year air quality data, which, owing to the recent data on vehicle trends, should hold promising results.

Other cities that launched their Clean Air Zones ahead of us are reporting the positive results of their CAZ’s, with research published in the Lancet last year demonstrating that CAZs and similar schemes successfully reduced pollution.

The London ULEZ is the best evaluated in the UK, with recent reporting demonstrating the incredible impact of the ULEZ in cleaning up the air(16). The health benefits will follow from this. These will be difficult to measure and count (counting what doesn't happen is difficult, especially when all the other factors that lead to heart and lung disease are also in the mix), but the case continues to be overwhelming.

The CAZ was not installed to be a permanent measure. But through it we hope to see permanent changes, for the better, for all who breathe Sheffield’s air, now and into the future.

To learn more about the Clean Air Zone in Sheffield, or to view the CAZ boundary please visit the website: 


1: Sheff News: 

1: Sheffield city Council Transport and Regeneration Committee Report: 

2: Royal College of Physicians & Royal College of Paediatrics and Child Health. Every breath we take: 2016: 

3: The Lancet - Health effects of low emission and congestion charging zones: a systematic review: 

4: Sheff News: 

5: World Health Organisation in 2021: 

6: England Chief Medical Officer 2022 report: 

7: The American Cancer Society: The Study That Helped Spur the U.S. Stop-Smoking Movement | American Cancer Society: 

7: The National Institue of Health - The Association Between Smoking Habits and Death Rates: 

8: Cancer Research UK – What is passive smoking? 

9: The Independent: Air pollution in cities ‘as bad for you as smoking 20 cigarettes a day’, says study - 

9: HouseFresh: Secondhand smoke world map: 

9: The Metro: London air pollution as bad as ‘smoking 154 cigarettes every year’:,level%20of%2022%20%C2%B5g%2Fm3. 

10: DEFRA /DfT: UK plan for tackling roadside nitrogen dioxide concentrations: 

11: City Changers: It Was No Easy Ride: Amsterdam’s Journey to Becoming a Cycling Icon's%20cycling%20story%20kicks,t%20a%20poor%20man's%20vehicle.%E2%80%9D 

11: The Guardian: How Amsterdam became the bicycle capital of the world: 

12: Nature Communications: Earth and Environment: Historical patterns and sustainability implications of worldwide bicycle ownership and use: 

13: TFL: New TfL data shows continued boom in walking and cycling: 

14: Connecting Sheffield: 

15: Better Points: / Sheffield City Council cycling safety courses: 

16: The Guardian: London ULEZ averts more air pollution than that caused by capital’s airports, report shows: 

16: Air Quality Consultants: Emissions savings from the ULEZ:  

16: Air Quality Consultants: Emissions savings from the ULEZ: