Airpocalypse now? Why pollution is the biggest environmental health risk of our age

By on

In 2012, according to estimates from the World Health Organisation, seven million people died across the world because of air pollution. Years after London’s ‘pea soupers’ and all the technological and legislative developments since then, how can air pollution now be the world’s largest environmental health risk?

While increases in wealth from economic growth may allow us to spread our wings, environmental burdens can quickly bring us down to earth with a bump. When it comes to air pollution, more and more people are asking whether enough is being done to reduce it. The high pollution levels we saw in March and April affecting London, Paris and other parts of western Europe seemed a surprise to many, a remnant of a previous age, of ‘pea soupers’ and gloomy street-lights in the 1940s, or more recent battles from the 1970s and 1980s about lead in petrol, acid rain or chlorofluorocarbons (CFC).

Perhaps we too hastily assumed that smog now only affects countries undergoing rapid industrialisation, like China. Or that the ‘green’ agenda is now merely about greenhouse gases which get the lion’s share of attention of policy-makers and activists. In fact the impact of atmospheric pollution is rapidly moving up the agenda of today’s global issues. The World Health Organisation (WHO) reported on 25 March 2014 that in 2012 around seven million people died – one in eight of total global deaths – as a result of air pollution exposure. 

In an interview with Safety Management, Caroline Russell, local transport spokesperson for the Green party in London, commented that she has recently seen the public become more aware of the situation. “Since the start of 2014 people are more worried about the floods and air pollution. People are realising that we do have one planet, one set of resources, and we need to use them carefully. Plus, of course, last year we heard that diesel particulates are causing cancer and that is a game changer. We are talking about a public health situation.” Recent figures from Public Health England put deaths in the UK due to long-term exposure to air pollution at 28,000 in 2010.

Air pollution comes from many different sources: factories, power plants, transport, heating and even wildfires. But, as Jon Goodbun explains, geography, in combination with weather, also plays a crucial part to amplify the effects of pollution. Jon is a senior lecturer in architecture at University of Westminster and runs the research lab Rheomode, which studies the linkages between architecture and the environment. “We can see that Athens, for example, sits inside a mountainous ‘bowl’ that can trap pollution and produces a ‘heat-island’ effect. Or London’s position within the Thames Valley encourages pollution to ‘sit’ on the city, particularly when you have warm days, cold nights and little wind, as was the case in early March.”

We have known for a long time that air pollution threatens the health of human beings, animals, plants, even the soil we stand upon. The London smogs culminated in the London fog of 1952 with the deaths of at least 4,000 people and the passing of the Clean Air Act in 1956. The latest estimate from the World Health Organisation puts annual global deaths from air pollution at seven million. The Today, Frank Kelly, Professor of environmental health at Kings College, London, says that air pollution is now the world’s largest single environmental health risk.

“The seven million figure is considerably greater than the previous WHO estimations and has roughly doubled since 2008.” Some of this, he accepts, is because of better monitoring through satellites and using mathematical models. Fundamentally though, “it is about the global migration from the country to the city, exposing more people to pollution, in particular in India and China. That’s why the figures have jumped so dramatically.”

For the first time in history more people live in cities than in the country. The population of the world is being distributed across local cities connected – and dependent upon – a shared atmosphere. “Air pollution is a global issue because urbanisation is the unfolding global event of the present age,” he concludes.

Cities are not necessarily the causes of pollution, but the built environment is fundamental to how we address air pollution.

Talking scientifically
To understand its impact we need to understand more about the science of air pollution: what it is, how it impacts on humans and the environment, what causes it and how it spreads. According to Professor Kelly, “the main pollutants are particulate matter (PM) and certain gases. PMs can originate from crushing and burning coal, toxic organic compounds from transport, burning plants for heat or smelting and processing metals. Some materials, like black carbon, are produced directly [primary pollutants], for example by an engine exhaust.” PMs are classified into under-10 or under-2.5 microns in size, though for Professor Kelly “anything under 10 microns in diameter can get into your lungs, is really bad and the highest risk to human health.

He adds: “The two main gas pollutants are nitrogen dioxide [NO2] and ozone. The chemistry behind the formation of all these pollutants – particulates or gases – is complex. Some are actually formed and transformed as they react chemically with other elements in the atmosphere [secondary pollutants]. One of the most obvious chemically derived pollutants is ozone itself. It is not produced directly but via precursors, such as volatile organic compounds, created by man or by nature, which under the action of ultraviolet radiation from sunlight get converted into ozone.”

Our understanding of the impacts on human, animal and vegetable health of these pollutants has grown considerably in recent years. Pollutants at 2.5 microns in diameter are especially toxic for humans and animals because, once inhaled, they enter the bloodstream, potentially causing asthma, cancer and heart disease. For Professor Kelly the consequences are stark. “Up to about 10 years ago we had a pretty good understanding of what happened to the respiratory system of the lungs and why people with lung diseases suffered more when pollution was worse. In the last decade we have advanced our understanding to see that, in fact, the problems go beyond the lung, physically and chemically. That has opened up a new field of association between bad air quality and what we call circulatory diseases, basically, cardiovascular disease and stroke. Because these are such big killers, the fact is that we’re now throwing more resources into understanding air pollution field and we can trace more deaths to air pollution.

“There is also better understanding of pregnancy and the effects of pollution on the unborn child, as well as the effects on children’s health and growing up in cities. There is also more understanding about lung development. This is particularly significant as there is a window of time up to the age of 20 when the lung develops. After that it doesn’t grow, so if the lung has been restricted by pollution before the age of 20 then it won’t grow anymore.

“The biological mechanisms that are affected by pollution will run across all species that breathe air and use oxygen. It also goes into vegetative life, into crop production. We know that in times of high ozone concentration plants don’t grow so well. They shut down their stomata and recess until ozone concentration drops again. Pollution affects all living organisms.”

Origins, spread and measuring
Measuring air pollution is complex and there is no universal way to do it or any agreed limits. The air quality index is commonly used by governments in Europe, USA, Canada and some Latin American countries. It provides a number to inform the public about how polluted the air is, but different countries adopt their own methods to measure it.

Europe does have a common measurement with limit values set for individual pollutants. The scale goes from ‘very low’ to ‘very high’, from 0 to over 100. The USA has a different scale which measures from ‘good’ to ‘very hazardous’. However, in many cases these limits are less stringent than the WHO’s guidelines. 

Professor Kelly points out that the origins of pollution depend on which part of the world you are looking at. In Europe, given that most people live in cities “the biggest source of pollution is transport. Diesel has been a particular disaster. A decade ago one in 10 cars worked with diesel, now it’s six out of 10. This switch was encouraged by policy-makers in order to reduce greenhouse gas emissions. What wasn’t spotted was that diesel is 20 times more polluting than petrol engines”.

He adds: “How we produce energy is also important of course. If the energy is being produced in the vicinity of the city it will be a contributor to the pollution. Energy production for heating and cooking in private homes also generates pollutants. Then there is industry itself. It’s good to have industries like power stations away from cities.”

According to Professor Kelly Asia, and China in particular, has a combination of the problems western Europe had in the 1940s and 50s, namely a great deal of pollution from coal burning, along with the pollution from the transport sector, which at the time the west didn’t have.

“If you go to rural communities in India, Asia or Africa, partly as a result of the poverty, a lot of cooking and heating is done on open stoves using biomass and wood. This leads to very high pollutant levels in people’s homes. In India they use a lot of animal excreta dried as dung as a fuel source. All this leads to high pollution levels. If you look at the WHO statistics, really big numbers of deaths come from these parts of the world.”

One atmosphere
Clearly there is only one atmosphere, shared by all of us. Any pollution that goes into the atmosphere can move away from its source. Sometimes it won’t go very far; but the smaller pollutants can travel further and if the weather is, for example, windy, pollutants can move hundreds of miles from the source. Pollutants travel between cities, across borders. A shared atmosphere must, in principle, result in shared pollution.

Professor Kelly explains that in an urban environment like London, at any point in time there is about 50% pollution from what the city is producing and 50% from what is blown in from somewhere else. Of course, what London is producing is blowing out and affecting somewhere else. “That’s why you need the global treaties, but that doesn’t mean there are not things to be done at the local or national level as well,” he concludes. 

Like climate change, where greenhouse gases are distributed across the globe regardless of where the gases originate from, air pollution is increasingly global pollution, though pollutants are more subject to local conditions.

Responding to air pollution
Cities are not necessarily the causes of pollution, but clearly the built environment is fundamental to how we address air pollution. If cities are, as Jon Goodbun points out, “extended networks that incorporate not only the places that people live and work, but also the infrastructure to supply them with energy and food,” then the design of these networks and the materials that are deployed will determine how polluting they are.

“We can see in the car age that the design of cities and suburbs starts from the basis that people have cars,” explains Jon. “Houses are designed to house a car, shops are situated to require a car and places of work demand a car. We need to be much better at selling alternative ways of living – shop locally for locally produced stuff, for example, and ensuring this is not just a middle class choice but something for everyone.”

Responding to transport pollution is high on the agenda of the Green party. “We need to drastically change the way we run our city,” says Caroline. “We need to stop mixing heavy traffic flow and construction lorries with bikes and people walking. We need to discourage people from using cars; walking and cycling must be prioritised over vehicles. For example, no-one in London lives too far from schools or public transport to have to drive to pick up their children.”

Amid the whirl of campaigning from her office/kitchen for the forthcoming European and local elections, Caroline sets out what in her view is the right response to air pollution. “London is falling behind other cities. We need an ultra low emission zone (ULEZ) now, not by 2020 as promised by the London mayor. This will reduce the most polluting vehicles by not allowing cars made before 2008 into the zone or diesel vehicles made before 2014. This ULEZ also only encompasses the congestion zone and we think all inner London boroughs should be included.”

Caroline argues that the demand for cars should also be reduced. “The mayor is still talking about new huge road building schemes and tunnels. The problem with tunnels is that it allows more journeys and cuts off communities. In addition, entries and exits around tunnels are very polluting, if you live near them, your life is blighted, and we would want to see mass community resistance to such schemes.”

Caroline has been involved in community projects to compile evidence around air pollution from transport. She is concerned that reductions in local authority budgets will prevent us seeing the true picture of pollution. “Recently I mapped NO2 levels along Blackstock Road in north London by putting up diffusion tubes along the road near schools, health centres, shops and places where we could interact with different groups of people. These are plastic tubes fixed on lamp-posts, which have a membrane inside that gets exposed to NO2. Blackstock Road showed up to be 75% above EU safe limits. The aside roads used as cut-through or ‘rat runs’, were 50% above EU safe limits while other surrounding roads were 25% above.”

Further, she points out that there is now an opportunity to align transport and public health policy since public health is under local authority control. “Both policies should be aligned.”

Model of a proposed evaporative cooling tower to disperse the pollution affecting Athens.

The big jigsaw
Green spaces offer a myriad of solutions for leisure, production of food and to combat pollution. As Jon says, “it’s been known for a long time the important role greenery can play in breaking down pollution. Victoria Park was built in the 19th century to reduce pollution in the East End of London. On the whole, complex living systems can break down toxins if concentrations are not too high. Increasing the biodiversity of cities is also vital.”

This approach seems to be currently in favour with planning policy-makers who are bringing back to life ideas of garden cities in the form of new or eco towns.

Energy efficiency means that we get more from the energy we produce, therefore reducing the pollution that is created to meet our needs. Insulation is an important part of the jigsaw for Caroline. “Though in Germany they pay more per unit of energy, their energy bills are much lower than in the UK because their homes are very energy efficient. People from abroad are astonished at how poor London homes are. There should be public subsidy to insulate homes – it create jobs, reduces pollution and people can save money.”

Jon also describes more direct architectural responses. “A range of interesting materials are now being developed. There is an additive of titanium oxide that is being used with concrete which reacts with sunlight and takes out NO2 – this creates a salt on the surface that can be washed away by rain. So there are both natural solutions and material science solutions to pollution.”

The creation of cities from scratch based on sustainability principles has also been attempted by a number of countries. The results have been mixed so far. For Jon, Masdar City in Abu Dhabi, a project initiated in 2006, was one such opportunity. “It was supposed to use solely solar energy and other renewable energy sources, but they only built one quarter of it. There were no cars in the project but designers, rather than simply being anti-car, took seriously the freedom that cars provide, and asked themselves how they can run sustainably.”

Ten years ago Jon worked on a proposal that involved an even more direct approach. “In a competition for temporary architectures in Athens we looked at an evaporative cooling tower and came up with a proposal for a fabric tower that can be packed in the back of a van and inflated with helium which would lift the tower up. The pollution in Athens is only about 20 to 30m deep. The tower was about 40m high, so it would reach above the pollution level. Water veins were stitched into the fabric, which leak water down the inside surface of the tower. The water evaporates and this removes energy from the surrounding air and creates a substantial downdraft, drawing clean air above the pollution level, down through the tower to the ground level and streets. Having a network of these could help disperse the heat island that plagues Athens. If you can disperse into the environment, then, on the whole, living systems can cope and absorb, break down the rest.”

Air pollution and climate change
For Professor Frank Kelly there are synergies in reducing air pollution and removing greenhouse gas emissions. “Obviously the climate change agenda is really dominant, but in reality there is a lot of commonality between the two and any climate change measures to reduce the formation of black carbon will be beneficial for reducing pollution. The other short-term driver for tackling climate change is to reduce methane and methane is a precursor of ozone. Again, controlling methane means you can benefit air quality.”

Another synergy is the link between heating up the atmosphere and speeding up chemical processes that create pollutants, particularly secondary pollutants like ozone. For Professor Kelly, this is an area of science that needs more research. If you think about southern EU countries they tend to have higher ozone concentrations than northern Europe. So as we get more warming from higher concentrations of greenhouse gases, we would expect the background concentration of ozone to increase. Ozone is about the most powerful oxidant we come into contact with and so therefore the effects would be detrimental.

Masdar City, in Abu Dhabi, was supposed to only use solar energy and other renewable energy sources, but only one quarter of it has been actually built. Photograph: Forgemind ArchiMedia

Chinese politics
Reducing pollution from energy production is critical. China is the greatest warning of uncontrolled coal burning near population centres, where levels of pollution at times vary between ‘hazardous’ and ‘very unhealthy.’

The WHO has released data showing that lung cancer rates have doubled in the past decade. Between 350,000 and 500,000 Chinese people die prematurely each year because of the country’s disastrous air pollution, according to China’s former health minister Chen Zhu. This is the equivalent of the population of Bristol.

It doesn’t take much imagination to appreciate how horrible it must be to live in a highly polluted city. In fact for many people in China it is not a matter of imagination but a daily occurrence. Xingtai, for example, a city of more than seven million people southwest of Beijing, was hit by 129 days of “unhealthy air” or worse, the threshold at which pollution is considered at emergency levels. Beijing suffered 60 days of pollution above emergency levels, sparking reports of an “airpocalypse.”

Dr Li Yu, senior lecturer and course director for the MSc Eco-Cities at Cardiff University, has written on this topic in his book, The Chinese City and Regional Planning Systems, published earlier this year. He points out that 16 of the world’s 20 most polluted cities are located in China.

He explicitly links growth in GDP from economic production to loss of GDP from environmental degradation. “Although economic development has been maintained at a rate above 8% annually during the last three decades, the treatment of pollution has taken away about 8% of the GDP. In other words, economic development has been at the cost of reduced environmental quality and resources for later generations.”

Enviromental problems don’t stop at air pollution of course. “Chinese rapid development has brought water pollution and seriously impacted on water supply. According to the investigation by the ministry of Water Resources in the Eighth Five-Year Plan period (1991-95), 46% of a total of 700 rivers and 75% of the 50 major lakes in China were already polluted. Of the 19 urban rivers running through eight cities within the Yangtze River catchment area, 18 suffered from pollution problems, the most polluted ones being the Suzhou River in Shanghai and Qing River in Nanjing.”

This reduction in a people’s quality of life can easily tip-over into political resistance. Dr Li Yu says that this is recognised by the Chinese authorities, but within limits. “The National Plan on New Urbanization (2014-2020) seeks to deliver ‘ecological progress’ while ‘striving for green, low-carbon development’. However, the existing government’s response is inadequate to protect the environment. GDP increase has been the key criteria for assessing the performance of local government and local senior leaders; economic development is being regarded as an absolute principle since the 1980s. For environmental pollution to become a main concern for local authorities requires institutional building.”

With large-scale protests over environmental concerns increasing in size and frequency, China’s leaders are under pressure to find ways to ease public concerns about industrial pollution. “People gathered in Xiamen to protest against plans by China National Petroleum Corporation to build a plant in a nearby town which would produce hazardous chemical paraxylene [PX]” explains Dr Li Yu. “As long as the authorities place GDP growth above all considerations, it would seem such protests and pressure is bound to grow.”

Dr Li Yu notes that “there has been a policy of so-called ‘veto power’ to oppose any project that may create environmental pollution. The challenge is that in practice this power has often been abandoned by local authorities to increase local GDP.”

The future
The uptake of industrialisation and the search for constant economic growth worldwide is having serious consequences for the environment. Such consequences are becoming the dominant issues of our age because – unlike all the historical, national, ethnic and religious identities that separate and differentiate us – they go to the heart of our shared life-supporting planetary inheritance.

We all have a stake in the purity of our atmosphere and rivers, the fertility of soil and the division between land and sea. That means we all have a stake in actions that degrade them. Unlike climate change though there is little sign of international treaties to tackle this problem yet. Our attitude, Professor Frank Kelly says, is “redolent of how we treated smoking about 40 years ago. It’s the lack of understanding that is the real barrier to change.”

It seems likely, however, that air pollution, once it’s viewed as global pollution rather than local pollution, will in time drive political change and an adequate legal, international framework. If, in the meantime, we can keep breathing.

Further information:



Lawrence Waterman Chairman of British Safety Council-editedSMLL.jpg

Charity work: inspiring and professional

By Lawrence Waterman OBE's first column for Safety Management on 09 May 2018

It is always pleasing when expectations are exceeded, when people are surprised because their experience is so much better than what they were expecting. Here at the British Safety Council we have several ways of doing that, often employed in a combination that brings a smile to the lips.


Don’t take safety for granted

By Mike Robinson, chief executive of the British Safety Council on 11 May 2018

The principle of continual improvement has long been accepted as a key component of effective health and safety management, and the plan-do-check-act cycle is widely recognised throughout the world.

Future risk iStock-SMLL credit-zoranm.jpg

Good work for all, today and tomorrow

By Matthew Holder, head of campaigns at the British Safety Council, introduces a new report on future risk on 23 February 2018

The British Safety Council has produced a new literature review on how changes to the way we work are likely to change risks to our health, safety and wellbeing in the future.