New research has revealed 44 cities across the UK are in breach of the World Health Organisation's guidelines on air quality.
London, Manchester and Glasgow all feature on the list, which was released on 30 October by the Royal College of Physicians (RCP).
The cities exceed WHO's limit of particles smaller than 2.5 microns allowed in the atmosphere, which is set at 10µg/m3 (micrograms per cubic metre).
London, Southampton and Leeds were among the worst offenders at 15µg/m3, but the crown for most polluted air goes to Glasgow, coming in at 16µg/m3.
WHO also have a second indicator of air pollution, particles smaller than 10 microns, which 13 UK cities breached. Glasgow also topped that list at 23µg/m3 (the maximum is 20µg/m3).
All UK cities clear the European Union's limit which is notably less strict than WHO. European cities are allowed a maximum of 25µg/m3 for particles smaller than 2.5 microns before they face fines. For particles smaller than 10 microns, the limit is raised to 40µg/m3.
Sustainability lead at RCP Dr Toby Hillman said addressing the poor air quality was "an opportunity we should grasp with both hands."
"We know that high exposures in early life have a major effect on lung and cognitive development throughout an individual's life," Hillman said. "That is why it is the government's duty to improve the air we breath and to ensure that people across the UK are not exposed to such a preventable cause of death and illness."
The RCP report was hopeful the UK's commitment to phase out electricity generation from coal by 2025 would decrease air pollution. It also requests the government expands the Clean Air Zones (which fines high-polluting vehicles whenever they enter) nationwide.
The figures still pale in comparison however to China, where the Beijing-Tianjin-Hebei area still regularly reaches 60µg/m3 for 2.5 microns each day.