**Two Welsh Cities Feature in List of UK’s Most Polluted, Study Claims**
A recent study has placed two of Wales’ largest cities—Cardiff and Swansea—amongst the most polluted urban areas across the United Kingdom. According to new research conducted by HouseFresh, residents in both cities are breathing in air as toxic as smoking 131 cigarettes each year, a finding that has sparked debate over the accuracy and implication of such data.
The report, which examined levels of particulate matter (PM2.5) in numerous populated cities worldwide throughout 2024, converted these pollution measurements into a more attention-catching metric: cigarette equivalents. The intention was to highlight the potential health risks faced by city dwellers as a result of poor air quality, offering a stark visualisation of abstract data. Notably, Cardiff and Swansea were the only Welsh cities to appear in the top ranks for pollution, coming eighth nationally, alongside Kingston upon Hull.
Despite these findings, Swansea Council has voiced reservations about the methodology of the study. A council spokesperson stated that the data does not faithfully present the city’s air quality, insisting that Swansea’s current pollution levels remain within Welsh government guidelines. The spokesperson acknowledged that the area’s significant industrial presence might contribute to pollution, but emphasised ongoing collaborative work with Swansea University to both monitor and improve air quality and to encourage residents to adopt more environmentally friendly habits.
Similarly, Cardiff Council questioned the representation of the study’s data. In a statement, the authority reassured the public that all city air monitoring stations are currently recording pollutant levels well within legal boundaries. The council underscored its commitment to addressing air quality, citing targeted strategies such as retrofitting public transport vehicles and incentivising cleaner travel in a bid to further decrease dangerous emissions across the city.
Officials in Cardiff also called for a measured approach when interpreting the HouseFresh results, suggesting that the numbers may reflect modelled and projected data, rather than direct real-time monitoring. They pointed out that all monitoring locations and schools in Cardiff reported nitrogen dioxide (NO2) concentrations significantly below the 40 µg/m3 legal threshold, with the highest reading being just 22 µg/m3. According to the council, overall air quality is improving, with NO2 trends showing a consistent decline, even dropping below levels seen during the COVID-19 pandemic.
Nationally, Liverpool topped the study’s list, with air pollution in the Merseyside city equating to the inhalation of 171 cigarettes a year. Other English cities such as Worthing, Northampton and Manchester also featured prominently, with air quality in these areas leading to a cigarette equivalent well above 120 per annum, according to the study’s calculations.
The comparison of pollution exposure to cigarette consumption forms part of a growing trend to communicate invisible risks in more relatable terms. Public health experts continue to warn about the serious long-term effects of breathing polluted air, from respiratory diseases to an elevated risk of stroke or heart attack. However, local councils remain cautious about accepting broad-brush interpretations, instead pointing to progress and improvements facilitated through targeted policy and technological innovation, including clean air zones and emissions-mitigation schemes.
Environmental campaigners acknowledge that while Wales’ urban pollution is a serious concern, the reality on the ground is nuanced. Industrial activity, geography, public transport infrastructure, and weather patterns all play a significant role in air quality outcomes. Nevertheless, the presence of Welsh cities on a national polluted areas list is a timely reminder that further efforts are required to protect population health—especially for vulnerable groups such as children and the elderly.
As the conversation about urban air quality continues, many in Wales call for more granular, transparent, and regularly updated data to help inform both public behaviour and government policy. For Cardiff, Swansea, and other affected cities, balancing ambitions for economic growth with environmental responsibility is likely to remain a key issue in the years to come.