It's clear that the climate emergency is in fact also a health emergency.
Spikes in air pollution trigger hundreds of heart attacks, strokes and acute asthma attacks in English cities compared to days when the air is cleaner, according to new research.
A study by King's College London found there are significant short-term health risks caused by air pollution, as well as contributing to up to 36,000 deaths every year.
The study looked at data from nine English cities - London, Birmingham, Bristol, Derby, Liverpool, Manchester, Nottingham, Oxford and Southampton.
It found on high pollution days - days when pollutant levels were in the top half of the annual range - there were an extra 124 cardiac arrests on average.
The figure discounts cardiac arrests suffered by patients already in hospital and is based on ambulance call data.
The research also found there was an average of 231 additional hospital admissions for stroke, with an extra 193 children and adults hospitalised for asthma.
Simon Stevens, chief executive of NHS England, described the numbers as "a health emergency".
"As these new figures show, air pollution is now causing thousands of strokes, cardiac arrests and asthma attacks, so it's clear that the climate emergency is in fact also a health emergency," he said.
"Since these avoidable deaths are happening now - not in 2025 or 2050 - together we need to act now."
He added the NHS needed to radically reduce its own carbon footprint, as well as adapting its supply chain and transport to do its bit to cut pollutants.
The risk was found to be greatest in London, where high pollution days cause an extra 87 cardiac arrests on average, an extra 144 strokes as well as 74 children and 33 adults hospitalised for asthma.
Birmingham saw the second highest risk, with 12 more out-of-hospital cardiac arrests, 27 more admissions for stroke, with 15 extra children and 11 adults hospitalised for asthma.
Bristol, Liverpool, Manchester, Nottingham, Oxford and Southampton saw between two and six additional out-of-hospital heart attacks on high pollution days.
These cities saw an uptick of between two and 14 extra hospitalisations for stroke, and up to 14 extra admissions for asthma. Only Derby did not see an increase in heart attacks on high pollution days.
Among the long-term risks associated with high pollution levels are stunted lung growth and low birth weight.
The research also found cutting air pollution by a fifth would decrease incidents of lung cancer by between 5% and 7% across the nine cities surveyed.
Dr Heather Walton, health expert on the project at Environmental Research Group, King's College London, said: "The impact of air pollution on our health has been crucial in justifying air pollution reduction policies for some time, and mostly concentrates on effects connected to life-expectancy.
"However, health studies show clear links with a much wider range of health effects."
The figures were published ahead of the International Clean Air Summit this Wednesday hosted by Mayor of London Sadiq Khan and the UK100 this week.
The UK100 is a network of local government leaders, who have pledged to help their communities shift to 100% clean energy by 2050.
Polly Billington, director of UK100, said: "Local government needs additional powers and resources to address this public health crisis, alongside a timetable for when air pollution levels will meet World Health Organisation guidelines."
Andrea Lee, clean air campaigns and policy manager at ClientEarth, said: “King’s new research is a stark reminder of the impacts that air pollution has on people’s health across the country.
"Our air is filthy and clean air zones are the most effective way to clean it up in the shortest possible time. This is backed up by newest data from London that show that the Ultra Low Emission Zone reduced nitrogen dioxide pollution by 29 percent during a three-month period, compared to a scenario where no ULEZ was in place.
“These results are very encouraging and prove that we don’t have to accept dirty air solely because we live in towns and cities.
"National and local government have to work together to urgently create a national network of clean air zones, like the Ultra Low Emission Zone in London, with help and support for people and businesses to move on to cleaner forms of transport.”
The full report is due to be published in November.
Tess de la Mare is a reporter with PA.