As part of the Global Climate and Health Alliance’s #UnmaskMyCity initiative we teamed up with our members the Royal College of Physicians, the Royal College of Emergency Medicine and the Royal College of Psychiatrists, as well as Great Ormond Street Hospital and the Mayor of London’s Office, to highlight the comprehensive impacts of air pollution on our bodies, from our lungs to our mental health.

The video, featuring RCP President “Bod” cycling across London to interview specialists on air pollution was originally shown at the Mayor of London’s International Air Quality Conference, and you can watch it below

Reflecting on the conference, and the cycling journey he joined Bod for, Richard Smith discusses air pollution in London, how far we’ve come since the first Clean Air Act of 1956, how London compares to some rapidly developing cities, and what more we still need to do to protect the health of the public in London and across the UK.

Richard Smith, Chair, UK Health Alliance on Climate Change


I don’t think about what I’m breathing, but living in London I’m breathing filthy air. I can neither see nor smell the filth, but I’m now thinking about what I’m breathing after attending the Mayor of London’s conference on air quality last week.1 In a nutshell, air quality in London is poor but showing some signs of improvement; yet the quality of the air is far better than in many of the world’s megacities, particularly cities like Dhaka and Delhi in South East Asia.

London’s Great Smog of December 1952, which lasted five days, killed 4,000 in the immediate aftermath and up to 12,000 altogether.2 The lethal effect of the smog was not realised until undertakers ran out of coffins. The air was filled with sulphur particles and smelt of rotten eggs. I was living in London and nine months’ old. I remember subsequent smogs, and in memory I wore a scarf that turned yellow around my mouth and could not see my hand in front of my eyes. More recently I’ve experienced similar smogs in Beijing and Delhi.

The London smogs of the 50s led to the Clean Air Act on 1956, which meant that if you flew into London you could actually see the city. But now the pollutants in the air—carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone, and the particulate matter (PM10 and PM2.5)—are invisible. Two million people, including 400,000 children, in London are living with illegal levels of air pollution, said Shirley Rodrigues, deputy mayor for environment and energy. The pollution causes some 9000 deaths a year—a similar number to those who died in the Great Smog of 1952, but these deaths are spread over time, space, and cause and not so visible.

Illegal levels

I did, of course, know that London has high levels of air pollution (it’s often mentioned in the media), but I am typical in not paying much attention. This lack of attention and outrage is frustrating to those who campaign on air pollution, who reflect on how adulteration of food or water causes much greater concern.

Although air pollution may be bad in London, it is much worse in many places, particularly Africa and South Asia. Air pollution in Britain accounts for 560 DALYs (disability adjusted life years) per 100,000 people each year compared with 2,550 for India and 4,045 for Nigeria.3  WHO estimates that nine of 10 people in the world breath air that exceeds WHO limits, causing eight million deaths a year – 4.2 million from outdoor pollution and 3.8 million from indoor pollution.4

Back in the 50s when Austin Bradford Hill and Richard Doll were searching for the cause of the epidemic of lung cancer their favoured hypothesis of the cause was traffic pollution. They were right, but at that time smoking was the major cause, but now smoking has declined. Air pollution does cause lung cancer, but it also contributes to chronic obstructive pulmonary disease (COPD), asthma, respiratory infections, heart disease, stroke, dementia, impaired child development, and low birth weight and prematurity in the newborn. Research continues to show new connections with disease.

Air pollution and the climate emergency share the same causes, and the 2015 Paris Agreement within the United Nations Framework Convention on Climate Change includes a commitment to clean air for everybody by 2030. Christiana Figueres, executive secretary of the UN Framework Convention on Climate Change, has called it “the most important health agreement ever,” and 195 countries have signed it, although President Trump has pulled the US out of the agreement. The agreement requires countries to do better every five years, and next UN climate change summit (known as COP26) will be held in Glasgow next year. Maria Neira, the head of air pollution for WHO, said that COP26 should be a “health COP.” “Health,” she said, “can be the motivator, the engine for tackling air pollution and the climate emergency.”

“Most important health agreement ever”

Outdoor air pollution is worse in cities, and C40 Cities Climate Leadership Group (C40) is a group of global cities working to combat the climate emergency and air pollution. Started by Ken Livingstone, who was then London mayor, in 2005 C40 now confusingly includes 94 cities, half of them in low and middle income countries. The cities contain around a twelfth of the world’s population and account for a quarter of the global economy. More than half the world’s population now live in cities, and politically they become increasingly important not least because they find it easier to reach agreement than nations—think of London voting 60% against Brexit.

The cities learn from each other and compete to be top of the class. The London Mayor Sadiq Khan has put combating air pollution at the centre of his commitments, and one initiative that has interested other cities is the ultra low emission zone (ULEZ). Begun in April this year, it means that all but very clean cars and vans must pay £12.50 to enter the zone, which covers the centre of London. An initial evaluation, said Rodrigues, shows that nitrogen dioxide has declined by 29%.5 Carbon dioxide emissions from transport have also declined by 4%. The proposal is to extend the zone in 2021. There are also many other initiatives, including increasing electric buses and charging points for electric cars, said Rodrigues. But the main aim must be to reduce car use and increase the number of people walking, cycling, and using public transport.

NO2 down by 29%

Rodrigues also made clear that London will not be able to achieve WHO limits on air pollution without the city being given more powers by the government —for example, over construction. Indeed, national progress will be necessary for London to achieve the limits. The UK Health Alliance on Climate Change was prominent at the meeting, with Nicky Philpott, our Director, leading a session, and a film that the Alliance produced being shown. The film featured Andrew Goddard (known to all as Bod), the President of the Royal College of Physicians, cycling through London with an air quality monitor on his bike and interviewing various people, including Wendy Burn, the president of the Royal College of Psychiatrists, about the health effects of air pollution. His trip ended with an interview with Rodrigues at City Hall.

Watch the full video below:

WHO limits for all

While London, and some other local authorities, have made some important steps in the right direction, it’s clear that to protect the health of people across the UK, we need to enshrine tough limits to air pollution in law. Currently, our air pollution targets (which are frequently exceeded) are in some cases (e.g. for PM2.5 pollution) more than twice as high as recommended by the WHO.

During this general election campaign, on behalf of over 650,000 health professionals across the country, the UK Health Alliance on Climate Change is calling for all political parties to support a legally binding, enforceable commitment to meeting WHO recommended PM2.5 limits by 2030.

The co-benefits of such action are clear – air pollution is linked to over 40,000 early deaths in the UK each year, and just a 1μg/m3 reduction in PM2.5 concentration this year could prevent 50,000 new cases of heart disease and 9,000 new cases of asthma. Currently air pollution costs this country around £22.2bn a year in related health and social care. Improving air quality will also reduce CO2 emissions, enabling the next Government to put the UK firmly on the path to meeting our commitment to net zero emissions before 2050.

As part of the Global Climate and Health Alliance’s #UnmaskMyCity initiative we teamed up with our members the Royal College of Physicians, the Royal College of Emergency Medicine and the Royal College of Psychiatrists, as well as Great Ormond Street Hospital and the Mayor of London’s Office, to highlight the comprehensive impacts of air pollution on our bodies, from our lungs to our mental health.

The video, featuring RCP President “Bod” cycling across London to interview specialists on air pollution was originally shown at the Mayor of London’s International Air Quality Conference, and you can watch it below

Reflecting on the conference, and the cycling journey he joined Bod for, Richard Smith discusses air pollution in London, how far we’ve come since the first Clean Air Act of 1956, how London compares to some rapidly developing cities, and what more we still need to do to protect the health of the public in London and across the UK.

Richard Smith, Chair, UK Health Alliance on Climate Change


I don’t think about what I’m breathing, but living in London I’m breathing filthy air. I can neither see nor smell the filth, but I’m now thinking about
what I’m breathing after attending the Mayor of London’s conference on air quality last week.1 In a nutshell, air quality in London is poor but showing some signs of improvement; yet the quality of the air is far better than in many of the world’s megacities, particularly cities like Dhaka and Delhi in South East Asia.

London’s Great Smog of December 1952, which lasted five days, killed 4,000 in the immediate aftermath and up to 12,000 altogether.2 The lethal effect of the smog was not realised until undertakers ran out of coffins. The air was filled with sulphur particles and smelt of rotten eggs. I was living in London and nine months’ old. I remember subsequent smogs, and in memory I wore a scarf that turned yellow around my mouth and could not see my hand in front of my eyes. More recently I’ve experienced similar smogs in Beijing and Delhi.

The London smogs of the 50s led to the Clean Air Act on 1956, which meant that if you flew into London you could actually see the city. But now the pollutants in the air—carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone, and the particulate matter (PM10 and PM2.5)—are invisible. Two million people, including 400,000 children, in London are living with illegal levels of air pollution, said Shirley Rodrigues, deputy mayor for environment and energy. The pollution causes some 9000 deaths a year—a similar number to those who died in the Great Smog of 1952, but these deaths are spread over time, space, and cause and not so visible.

Illegal levels

I did, of course, know that London has high levels of air pollution (it’s often mentioned in the media), but I am typical in not paying much attention. This lack of attention and outrage is frustrating to those who campaign on air pollution, who reflect on how adulteration of food or water causes much greater concern.

Although air pollution may be bad in London, it is much worse in many places, particularly Africa and South Asia. Air pollution in Britain accounts for 560 DALYs (disability adjusted life years) per 100,000 people each year compared with 2,550 for India and 4,045 for Nigeria.3  WHO estimates that nine of 10 people in the world breath air that exceeds WHO limits, causing eight million deaths a year – 4.2 million from outdoor pollution and 3.8 million from indoor pollution.4

Back in the 50s when Austin Bradford Hill and Richard Doll were searching for the cause of the epidemic of lung cancer their favoured hypothesis of the cause was traffic pollution. They were right, but at that time smoking was the major cause, but now smoking has declined. Air pollution does cause lung cancer, but it also contributes to chronic obstructive pulmonary disease (COPD), asthma, respiratory infections, heart disease, stroke, dementia, impaired child development, and low birth weight and prematurity in the newborn. Research continues to show new connections with disease.

Air pollution and the climate emergency share the same causes, and the 2015 Paris Agreement within the United Nations Framework Convention on Climate Change includes a commitment to clean air for everybody by 2030. Christiana Figueres, executive secretary of the UN Framework Convention on Climate Change, has called it “the most important health agreement ever,” and 195 countries have signed it, although President Trump has pulled the US out of the agreement. The agreement requires countries to do better every five years, and next UN climate change summit (known as COP26) will be held in Glasgow next year. Maria Neira, the head of air pollution for WHO, said that COP26 should be a “health COP.” “Health,” she said, “can be the motivator, the engine for tackling air pollution and the climate emergency.”

“Most important health agreement ever”

Outdoor air pollution is worse in cities, and C40 Cities Climate Leadership Group (C40) is a group of global cities working to combat the climate emergency and air pollution. Started by Ken Livingstone, who was then London mayor, in 2005 C40 now confusingly includes 94 cities, half of them in low and middle income countries. The cities contain around a twelfth of the world’s population and account for a quarter of the global economy. More than half the world’s population now live in cities, and politically they become increasingly important not least because they find it easier to reach agreement than nations—think of London voting 60% against Brexit.

The cities learn from each other and compete to be top of the class. The London Mayor Sadiq Khan has put combating air pollution at the centre of his commitments, and one initiative that has interested other cities is the ultra low emission zone (ULEZ). Begun in April this year, it means that all but very clean cars and vans must pay £12.50 to enter the zone, which covers the centre of London. An initial evaluation, said Rodrigues, shows that nitrogen dioxide has declined by 29%.5 Carbon dioxide emissions from transport have also declined by 4%. The proposal is to extend the zone in 2021. There are also many other initiatives, including increasing electric buses and charging points for electric cars, said Rodrigues. But the main aim must be to reduce car use and increase the number of people walking, cycling, and using public transport.

NO2 down by 29%

Rodrigues also made clear that London will not be able to achieve WHO limits on air pollution without the city being given more powers by the government —for example, over construction. Indeed, national progress will be necessary for London to achieve the limits. The UK Health Alliance on Climate Change was prominent at the meeting, with Nicky Philpott, our Director, leading a session, and a film that the Alliance produced being shown. The film featured Andrew Goddard (known to all as Bod), the President of the Royal College of Physicians, cycling through London with an air quality monitor on his bike and interviewing various people, including Wendy Burn, the president of the Royal College of Psychiatrists, about the health effects of air pollution. His trip ended with an interview with Rodrigues at City Hall.

Watch the full video below:

WHO limits for all

While London, and some other local authorities, have made some important steps in the right direction, it’s clear that to protect the health of people across the UK, we need to enshrine tough limits to air pollution in law. Currently, our air pollution targets (which are frequently exceeded) are in some cases (e.g. for PM2.5 pollution) more than twice as high as recommended by the WHO.

During this general election campaign, on behalf of over 650,000 health professionals across the country, the UK Health Alliance on Climate Change is calling for all political parties to support a legally binding, enforceable commitment to meeting WHO recommended PM2.5 limits by 2030.

The co-benefits of such action are clear – air pollution is linked to over 40,000 early deaths in the UK each year, and just a 1μg/m3 reduction in PM2.5 concentration this year could prevent 50,000 new cases of heart disease and 9,000 new cases of asthma. Currently air pollution costs this country around £22.2bn a year in related health and social care. Improving air quality will also reduce CO2 emissions, enabling the next Government to put the UK firmly on the path to meeting our commitment to net zero emissions before 2050.