Two studies by scientists in the US - both published in The Lancet Planetary Health - looked at the effects of nitrogen dioxide (NO2) and fine particulate pollution.

In 2019, nearly two million cases of asthma among children worldwide were attributed to NO2 pollution at levels exceeding the World Health Organisation (WHO) guidelines from 2005.

Modelling also suggested there are currently 2.5 billion people living in areas with unhealthy levels of fine particulate matter in the air.

Rosamund Kissi-Debrah's daughter Ella died in 2013 after suffering a fatal asthma attack.

In the three years before, she had visited the hospital nearly 30 times and had endured seizures.

In a second inquest, air pollution was ruled to be the cause of Ella's death.

Ms Kissi-Debrah told Sky News: "The quality of her life once the asthma had taken hold was never the same again and every time there was a spike in air pollution she ended up in hospital.

"Three months before her seventh birthday that's when we first noticed it, when she developed a severe cough.

"She was born right next to the South Circular and obviously that's where her last breath was taken so for all of Ella's life she was breathing illegal air."

Ms Kissi-Debrah says governments and world leaders have "a duty of care" to their citizens, and that "they need to start acting right now".

She said "it's absolutely shocking and devastating" to once again be reading about excess deaths attributable to air pollution.

Dr Audrey de Nazelle, co-director of the Centre for Environmental Policy at Imperial College London, told Sky News air pollution is detrimental because "it really attacks every organ in our body, it comes deep into our lungs, in some cases the very fine particles into the bloodstream and affects pretty much anything."

She said it is vital "we really transform our cities, so it is easy to walk or take public transportation" as driving is one of the most problematic factors.

Dr de Nazelle added: "We all need to get engaged and put pressure on our politicians because that's what's going to change things."

A government spokesperson said: "Air pollution has reduced significantly since 2010 - at a national level emissions of fine particulate matter have fallen by 11%, while emissions of nitrogen oxides are at their lowest level since records began - but we know there is still more to do."