Aston University pollution expert praises Clean Air Zone roll out plans across UK

Nov 2, 2021

4 min

Dr Stephen Worrall


• Dr Stephen Worrall believes Birmingham’s Clean Air Zone is encouraging fewer drivers into city centre

• The pollution expert said statistics show motorists are ‘changing their behaviour’

• He praised other cities for following suit but says changes need to come more quickly.


A leading expert in air pollution from Aston University has examined available data on how many vehicles have paid to enter Birmingham’s Clean Air Zone (CAZ) and has said people’s behaviours are changing



Atmospheric chemist, Dr Stephen Worrall, praised the introduction of Birmingham’s CAZ which launched on 1 June, saying it was an important step in tackling air pollution in the city and would have a considerable impact on people’s health.


Whilst the full impact of the CAZ on pollution levels won’t become clear until 2022, Dr Worrall said since the “Go Live Date” the traffic data revealed that the number of non-compliant vehicles being driven in the zone was decreasing markedly.


“In the first two weeks of June before charging was introduced, the daily number of non-compliant vehicles being driven within the CAZ was at an average of 18,787.


“After charging was introduced, this dropped significantly to 11,850 for the remainder of June and this number has continued to fall, with the last reported daily average of 10,800 for August.


“This isn’t just your average motorist with a car either, as the data shows similar trends for other categories of vehicles with the biggest improvement observed in light goods vehicles (LGVs). Over 75% of these vehicles were complying with the CAZ in August versus just 63% in June. This is a significant and sustained reduction which clearly demonstrates that people are modifying their behaviours,” he said.


Dr Worrall added that the data was also able to hint at the manner in which people were modifying their behaviour, with a possible increase in public transport use, car sharing or a reduction in overall number of journeys.


“Some people are upgrading their vehicles to newer, less polluting models as there has been a small rise of about 2,500 in the number of complaint vehicles entering the CAZ on a daily basis. However, this number is dwarfed by the approximately 8,500 reduction in the daily number of non-complaint vehicles. The upshot of this is that the total number of vehicles entering the CAZ every day has dropped by roughly 6,000 (around 6%). 6,000 fewer of the most polluting vehicles in our city centre is a real positive and a step in the right direction to improving our air quality and health,” he said.


Air pollution particularly affects the most vulnerable in society, including children, and older people, and those with heart and lung conditions. The annual health cost to society of the impacts of particulate matter alone in the UK is estimated to be around £16 billion*.


Levels of NO2 in Birmingham frequently exceed 45 to50 micrograms per cubic meter, mainly caused by road traffic emissions, with certain hotspots exhibiting even greater values such as the measuring site at St Chads Queensway where the last reported yearly average for the city centre was as high as 74 micrograms per cubic meter. The primary aim of the CAZ is to reduce the levels of NO2 to 40 micrograms per cubic meter.


Dr Worrall said that although CAZs weren’t directly designed to address greenhouse gas emissions, if as suggested they result in less people using their vehicles for journey, then this would have an impact on emissions.


“Whilst the CAZ target is to reduce nitrogen dioxide (NO2) levels, the knock-on effect of this reduction in car use will mean a reduction in pollution in general, including greenhouse gases such as CO2. This is really important and suggests that other cities need to be acting now rather than later. Bath has implemented a similar but less stringent system, London recently extended its ultra low emission zone (ULEZ) area and Portsmouth’s CAZ will be coming live shortly too, but other cities who have plans in the pipeline should really bring them forward as a matter of urgency,” he said.


Dr Worrall added that with current COP26 discussions bringing pollution to the forefront, it was important to continue with awareness.


“These policies are all small pieces in the puzzle for reducing emissions from transport and getting people to make wiser choices about the vehicles they own and buy, and as COP26 is making very clear we need to be doing all of these things now to save our planet” he said.


Dr Worrall has great experience in the subject, having spent a portion of his post-doctoral research in Beijing where he took live air pollution measurements, monitored problematic levels and discussed with international colleagues’ ways to address these issues.


Read more about the College of Engineering and Physical Sciences at Aston University, here: https://www.aston.ac.uk/eps


ENDS

* Defra (2017) Air quality plan for nitrogen dioxide in the UK


Connect with:
Dr Stephen Worrall

Dr Stephen Worrall

Deputy Head of Chemical Engineering and Biotechnologies

Dr Worrall's research interests in novel methods for nanomaterial coating production for energy storage and pollution management.

Thin Films and NanotechnologyNanomaterials SynthesisMaterial CharacterizationMaterial CharacteristicsThin Film Deposition
Powered by

You might also like...

Check out some other posts from Aston University

Twin earthquakes in Venezuela raise serious concerns over humanitarian, health and infrastructure impacts featured image

3 min

Twin earthquakes in Venezuela raise serious concerns over humanitarian, health and infrastructure impacts

Dr Komal Raj Aryal, lecturer in crisis and disaster management at Aston Business School, has expressed serious concern following the powerful twin earthquakes that struck northern Venezuela on 24 June 2026. "The back-to-back earthquakes, measuring magnitude 7.2 and 7.5 and occurring within less than a minute of each other at an approximate depth of 22 km, represent an exceptionally severe seismic event," said Dr Aryal, who has more than 26 years of international research experience in earthquakes, landslides, extreme weather events and disaster risk governance. "The combination of two major earthquakes occurring in rapid succession, their relatively shallow depths, and the repeated strong ground shaking is likely to have substantially increased damage to buildings, transport networks and other critical infrastructure. Scientifically, a magnitude 7.5 earthquake releases approximately three times more energy than a magnitude 7.2 event. Experiencing both events within seconds creates an extremely complex emergency response situation." Dr Aryal highlighted particular concern for San Felipe, an important industrial, commercial and transportation centre with a population of more than 300,000 people. Built across hilly terrain, with steep streets and dense urban development, the city could face significant challenges for emergency access, search and rescue operations, evacuation and humanitarian assistance. Around 10% of the city's population is aged 65 or older, making older adults particularly vulnerable during prolonged emergency situations. "If widespread power outages occur while temperatures remain between 32°C and 35°C, communities will face compounded risks including heat stress, disruption to healthcare services, shortages of clean water, communication failures and interruptions to essential public services. These cascading impacts often become as significant as the direct earthquake damage itself." Based on the available seismic information and preliminary footage shared on social media, Dr Aryal noted that it will likely take days or even weeks before authorities fully understand the extent of structural damage across northern Venezuela. "Initial seismic information suggests a rupture along a major fault system parallel to Venezuela's northern coastline, with areas experiencing extremely intense ground shaking. If confirmed, significant cascading impacts may extend well beyond the epicentral area, affecting multiple urban centres, transport corridors and regional supply chains." Dr Aryal also expressed concern about the resilience of Venezuela's healthcare system. "Northern Venezuela contains a large concentration of hospitals and healthcare facilities. At present, it remains unclear how many medical facilities have been affected by the earthquakes. Any disruption to hospitals, combined with existing pressures on healthcare capacity, medicine supplies and emergency logistics, could significantly affect the delivery of healthcare services for both acute injuries and patients with chronic illnesses." He added that damage to airports, major highways, bridges and other transport infrastructure could delay humanitarian assistance, emergency logistics and economic recovery. "The humanitarian consequences of this disaster will depend not only on the severity of the ground shaking, but also on the resilience of critical infrastructure, the effectiveness of emergency coordination, the availability of healthcare services and the country's broader socioeconomic capacity to recover." Dr Aryal further warned that the immediate earthquake sequence is unlikely to mark the end of the crisis. "Strong aftershocks are highly likely following earthquakes of this magnitude. These may continue for months, and some could themselves be damaging. They increase risks to already weakened buildings, complicate search and rescue operations, trigger additional landslides in mountainous areas, and prolong humanitarian needs." He concluded that while casualty figures and the full extent of the damage remain uncertain, the event has the potential to become one of the most significant seismic disasters in the region in recent years, requiring sustained national and international humanitarian support.

The world is burning useful waste, and cleaner alternatives are needed featured image

4 min

The world is burning useful waste, and cleaner alternatives are needed

When we talk about clean air, the conversation usually turns to traffic: exhaust fumes, congestion, school runs and the air people breathe on busy streets. That focus is understandable because road transport remains one of the most visible sources of poor air quality in everyday life. But Clean Air Day should also draw attention to a less visible question: why are useful materials still being burned as waste? Clean air is about more than traffic Around the world, huge quantities of leftover straw are still treated as waste to be cleared quickly, with rice straw one of the clearest examples. More than 700 million tonnes of rice straw are produced globally every year, and around 80% is burned. That contributes directly to air pollution and greenhouse gas emissions, while also destroying material that could have value. At Aston University’s Energy and Bioproducts Research Institute, researchers are exploring alternatives to open burning of crop residues, including whether materials often treated as waste could instead become useful sources of energy, fuels or bioproducts. This matters because the clean air debate needs to look beyond transport. How we manage waste, land and energy also plays a part, and agricultural residues should not automatically be seen as rubbish to be burned. In many cases, they could be resources with real value. Why burning crop waste matters The World Health Organization describes air pollution as one of the greatest environmental risks to health, estimating that ambient outdoor air pollution caused 4.2 million premature deaths globally in 2019. Much of that risk comes from exposure to fine particulate matter, which is linked to cardiovascular and respiratory disease and cancers. That is particularly relevant when residues are burned in the open, as smoke and fine particles can travel beyond the field where burning takes place, affecting nearby communities and wider air quality. There is a practical issue as well as an environmental one. If burning is the fastest and cheapest way to clear land, it can easily become the default, which is why any cleaner alternative has to work for farmers and communities in practice. It is not enough to tell people to stop burning; they need practical alternatives that make sense economically and locally. Turning waste into cleaner alternatives Biochar and bioenergy are two examples of how waste crop material can be treated differently. Instead of being burned in the open, residues can be converted into useful products or sources of renewable energy. Biochar can also offer practical benefits for farmers when it is produced and applied appropriately. Studies have shown that addition of biochar to the soil can improve its structure, help retain nutrients and, in some cases, reduce the need for synthetic fertilisers, which will lower associated emissions and economic demands. The water-holding capacity of biochar can also support crops during dry periods, potentially reducing irrigation demand in drought-prone seasons. Work connected to rice straw has shown that cleaner alternatives to burning can produce measurable environmental benefits while supporting local economies. Community-scale rice straw bioenergy systems, for example, can avoid 2.7–3.5 tonnes of CO₂ equivalent emissions per hectare each year, while creating fuel savings and reducing post-harvest losses for rice farming communities. Research and interviews have shown that farmers and local stakeholders are willing to participate in these transitions when alternatives are designed around their needs and priorities. During community engagement activities, participants consistently highlighted cleaner air as an important benefit, not only for environmental reasons but also because of concerns about the health impacts of smoke and the financial burden of illness. For many households, avoiding respiratory problems and expensive hospital bills was seen as just as important as generating additional income from agricultural residues. That matters because cleaner air is linked to more than one policy area. Transport is important, but so are farming, energy and waste. Research can help identify what works, where the trade-offs are, and how promising ideas can move beyond the lab. It can also support industry, policymakers and local partners to develop alternatives that are practical rather than theoretical. For policymakers, the lesson is that air quality cannot be improved by focusing only on the most visible sources of pollution. Transport matters, but so do homes, industry, farming, waste and energy systems. There is no single answer. Agricultural residues vary, local conditions vary, and technologies need to be assessed carefully, but cleaner air will require better options than burning. Clean Air Day should prompt us to ask why useful materials are still being burned in the first place. If we want cleaner air, we need to reduce what we burn and get smarter about what we waste. This article was written by Dr Samuel Sogbesan and Thea Mae Baltazar from Aston University’s Energy and Bioproducts Research Institute. (Photo by Sandie Peters on Unsplash)

Major trial shows increasing bone density fails to cut fracture risk in brittle bone disease featured image

3 min

Major trial shows increasing bone density fails to cut fracture risk in brittle bone disease

An international clinical trial involving Aston University researchers has challenged long held assumptions about how brittle bone disease is treated in adults, after finding that substantially increasing bone density did not reduce the risk of fractures. The study, published in the Journal of the American Medical Association (JAMA), examined whether a two stage treatment using the bone building drug teriparatide followed by the bone preserving drug zoledronic acid could reduce fractures in adults with osteogenesis imperfecta, often referred to as brittle bone disease, a rare genetic condition that causes bones to break easily throughout life. Researchers followed 349 adults treated at 27 specialist centres across the UK and Europe. While the treatment led to clear increases in bone density in the spine and hip, fracture rates were no lower than among patients receiving standard care, suggesting that bone quality may matter more than bone density alone in preventing fractures in people with the condition. The findings underline a key distinction between brittle bone disease and more common bone conditions such as osteoporosis, where increasing bone density is known to reduce fracture risk. In osteogenesis imperfecta, the study suggests that bones can become denser without becoming less likely to break, indicating that the underlying quality and structure of bone tissue may play a greater role in fracture risk than density alone. Dr Zaki Hassan Smith, an endocrinologist at Aston Medical School who contributed to the research, said: “This study shows that in osteogenesis imperfecta, simply increasing bone density doesn’t necessarily translate into fewer fractures. That’s important, because it tells us that the disease is more complex than what we see on a scan. The findings help shift the focus towards understanding bone quality and how bones behave in real life, which is essential if we are to develop more effective treatments that genuinely reduce harm for patients.” Osteogenesis imperfecta is a genetic condition that affects collagen, leaving bones fragile and prone to fracture throughout life. There is currently no licensed treatment specifically approved to prevent fractures in adults with the condition, and patients often experience repeated fractures, chronic pain and long term disability. The trial tested a sequential treatment strategy commonly used in osteoporosis, where a bone building drug is followed by a treatment designed to preserve gains in bone strength. Although this approach successfully increased bone density in people with osteogenesis imperfecta, it did not reduce fracture rates, suggesting that treatment strategies effective in osteoporosis may not directly translate to rare bone diseases. Researchers did observe improvements in some quality of life measures among participants receiving the treatment, including reduced pain interference and improved mobility. However, fracture prevention remained unchanged, reinforcing the need for new approaches that target the fundamental properties of bone in osteogenesis imperfecta rather than density alone. The study was led by the University of Edinburgh and funded by the Medical Research Council and the National Institute for Health and Care Research. Aston University contributed clinical and academic expertise through Aston Medical School as part of the large international collaboration, which involved specialist centres across the UK and Europe. The study was led by the University of Edinburgh, with Aston University contributing clinical and academic expertise as part of a wider international collaboration involving multiple specialist centres across the UK and Europe. The research was funded by the Medical Research Council and the National Institute for Health and Care Research. Researchers say the findings provide important guidance for future research, helping to steer efforts towards treatments that focus on bone quality, strength and resilience in everyday life. They also highlight the value of large scale clinical trials in rare diseases, where learning what does not reduce harm is an essential step towards better care. The paper, Teriparatide Plus Zoledronic Acid for Osteogenesis Imperfecta, is published in JAMA. https://doi.org/10.1001/jama.2026.6889

View all posts