Declining Mortality Linked to Improved London Air Quality

There has been a significant decline in air pollution-related deaths in London following the implementation of stricter emissions policies through the phased expansion of the Ultra Low Emission Zone, which now covers over nine million Londoners.

An independent analysis by Imperial College London's Environmental Research Group found that deaths from poor air quality fell by approximately 40% between 2019 and 2024.

Decline in urban air pollutants

Some of the findings from the research go beyond simply a cut in carbon emissions.

Fine particulate matter, which penetrates deep into the respiratory system, decreased by 28%. Meanwhile, nitrogen dioxide concentrations fell by 41%.

These pollutants are closely linked to serious health issues, including impaired lung development in children, increased lung cancer risk and higher rates of cardiovascular disease.

However, updated methodologies show that long-term exposure to urban emissions poses a greater health risk than previously estimated.

Revised data indicate that annual premature deaths fell from 6,400–8,000 in 2019 to 3,800–5,100 in 2024.

The findings reinforce the connection between poor air quality and chronic conditions such as dementia, type 2 diabetes, and childhood asthma.

"A 40% reduction in deaths linked to air pollution in just five years is a remarkable public health achievement,” says Jane Burston, CEO, Clean Air Fund.

“This research adds to a growing body of evidence that clean air measures, like London’s ULEZ (Ultra-Low Emission Zone), save lives. This progress reflects ongoing efforts by city leaders, civil society organisations, and communities that have pushed for ambitious action.”

Reduced pressure on healthcare systems

The environmental improvements seen in the UK’s capital have had a measurable effect on the health of the city’s population.

Previous data from Imperial College London found that anti-pollution measures led to a 9.3% reduction in emergency hospital admissions for cardiac conditions.

Overall admissions for all medical conditions within the ULEZ declined by 5.1%, easing pressure on the UK’s National Health Service.

“These findings are a reminder of what is at stake when we talk about air quality," says Karen Bonner, Chief Nurse for the NHS in London.

"Thousands of Londoners are now living longer, healthier lives because the air they breathe is cleaner. Children with asthma, elderly residents, and those with respiratory conditions are among those who benefit most.

"There is still more to do, but this data shows that sustained, evidence-led action to tackle air pollution saves lives and we are committed to continuing to work alongside the Mayor and our partners to protect the health of every Londoner.” 

Long way to go

Mete Coban, Deputy Mayor of London for Environment and Energy, was speaking at the Climate Group’s Opportunity Summit as part of London Climate Action Week on 23 June ahead of the publication of the data. He celebrated the progress made on London’s air quality, but added there was still a long way to go.

“When the mayor first got elected in 2016, experts and scientists told him it would take 193 years for us to reach the legal air quality limits here in London. We've done it in just nine years,” Mete explained.

“In just nine years, we managed to clean our air.  Now, there's still a long way to go because we're still committed to the WHO guidelines, but we've been able to do that by heavily investing.

“Climate change doesn't impact everyone equally. It impacts those who've done the least to cause the crisis in the first place.  

“And if we talk about pollution, there are so many young people, half a million people in our city who will never ever be able to breathe the full capacity of their lungs because of the crisis that they didn't cause in the first place, because we're dependent on fossil fuels, and every time those toxins go in the air, it stunts the lungs of our children.”

Beyond London

The data was released during London Climate Action Week, which gathers business executives and political leaders for a week of discussions and deals.

During the week, HRH Prince William’s Earthshot Prize published its Impact Report, marking five years of progress and showcasing the transformative impact of Earthshot Finalists.

The report found that Earthshot prize finalists had improved air quality in regions home to 600 million people - twice the population of the US.

“One day, people will look back at this decade and ask: when the evidence was clear, what did we do with it?” says Prince William.

“When we saw forests being restored, did we help restoration spread? When we saw clean air policies working, did we help other cities follow?  When we saw the energy systems transform, did we fully commit? When we saw communities on the front line becoming leaders in resilience, did we stand beside them?  

“That is the responsibility of this moment. And it is this story that matters, not just the problems we face, but the collective response to tackle them.   

“The challenge can still feel immense but the proof is now in front of us. And history will ask what we did with it.”