Research confirms traffic pollution responsible for triggering asthma in previously healthy children

Researchers at Leeds University have found that traffic pollution is responsible for previously healthy children developing asthma. The huge study, looking at about a million children, found that black carbon — oily soot particles emitted by diesel engines — is the main cause, with NO2 and particulates. All are emitted by road vehicles.  It is already known that higher levels of air pollution trigger asthma attacks in people who already have it, but the role of traffic pollution in initiating the condition in healthy children had not been confirmed before. A large number of schools in the UK are in areas with air quality below EU standards. The pollutants attack the lining of children’s lungs, initiating an inflammatory reaction that leads to asthma. Once triggered, the asthma reaction can happen again and again, causing numerous attacks through a person’s life. The research combined data from 41 epidemiological studies from countries including England, Holland, Germany, Sweden and the US. There are around 1.1m children in the UK with asthma, a near-threefold rise over the past 60 years. Also around 4.3m adults. On average 3 people die each day from it and costs the NHS about £1 billion per year.  Long-term exposure to air pollution in childhood is known to stunt lung growth and brain development. The asthma findings will cause further concerns about permitting increases in local air pollution, eg, with a 3rd Heathrow runway, or the government’s £11bn road-expansion programme.



Traffic fumes give asthma to children

By Jonathan Leake, Science Editor (Sunday TImes)
November 27 2016


Scientists have found that traffic pollution is responsible for turning healthy children into asthmatics — the first confirmation of such a link.

Long-term exposure to air pollution in childhood is known to stunt lung growth and brain development, while short-term surges in air pollution cause increased hospital admissions for heart attacks and strokes.


The Department for Environment, Food and Rural Affairs (Defra) estimates that NO2 pollution causes up to 23,500 premature deaths a year in the UK. Particulates are estimated to cause another 29,000 deaths.


Find out if your child’s school is in an air pollution hotspot: go to

Full Times article at


Traffic pollution increases risk of developing asthma in childhood

University of Leeds website

Children and adolescents exposed to high levels of traffic-related air pollution (TRAP) have a higher risk of developing asthma, according to a systematic review and large-scale analysis performed by researchers from the University of Leeds and the Barcelona Institute for Global Health (ISGlobal).

An estimated 334 million people suffer from asthma worldwide, and numerous studies show that the prevalence of childhood asthma has markedly increased since the 1950s. The factors underlying this increase are largely unknown, but changes in environmental exposures including air pollution are thought to be involved.

This new study, published in Environment International, is the largest and most up-to-date review and analysis of current evidence of exposure to traffic-related air pollution and the development of childhood asthma. The authors reviewed more than 4,000 articles published on the topic between 1999 and September 2016, and analysed the data from 41 epidemiological studies (from the Netherlands, the USA, Canada, Germany, Norway, Sweden, England, France, Italy, Japan, China, Taiwan, and Korea) which met criteria for inclusion in the systematic review. Khreis and co-authors then combined data for over a million children in meta-analyses, and showed that TRAP exposures increase the risk of childhood asthma development.

Haneen Khreis, researcher at the University of Leeds and lead author of the study, concludes that “according to the analysis we performed, combining data from multiple studies, we can now confirm that there is a positive association between TRAP exposures and development of childhood asthma”. In particular, the review looked at exposure to traffic-associated nitrogen dioxide, black carbon, and particulate matter (PM2.5 and PM10) during childhood, and the subsequent development of asthma. “Our analysis shows that the most robust effects were in association with black carbon exposures, a specific marker of traffic exhaust and a diesel-related pollutant, but more research is needed to draw definitive conclusions, including exploring the effects of non-exhaust pollutants”. With the roads in many cities now dominated by diesel vehicles, this research sheds more light on the public health consequences of transport policy.

“Air pollution has a great impact on childhood health” underlines Mark Nieuwenhuijsen, senior author of the study and director of the Urban Planning, Environment and Health Initiative at ISGlobal. He adds “Given that almost 70% of people globally are projected to live in urban areas by 2050, exposure to traffic-related air pollution is a major global health problem and we need to act quickly”.

Read more:

Exposure to traffic-related air pollution and risk of development of childhood. A systematic review and meta-analysis.



40,000 deaths a year linked to air pollution

Published:  23 February 2016
Southampton University

A new report, involving researchers from the University of Southampton, starkly sets out the dangerous impact air pollution is currently having on our nation’s health – with around 40,000 deaths a year linked to air pollution.

Entitled ‘Every breath we take: the lifelong impact of air pollution’, the report says the harm from air pollution is not just linked to short term episodes but is a long term problem with lifelong implications.

The report notes examples from right across an individual’s lifespan, from a baby’s first weeks in the womb through to the years of older age. Examples include, the adverse effects of air pollution on the development of the fetus, including lung and kidney development, and miscarriage, increases in heart attacks and strokes for those in later life; and the associated links to asthma, diabetes, dementia, obesity and cancer for the wider population.

Stephen Holgate, Medical Research Council Clinical Professor of Immunopharmacology at the University of Southampton, chaired the working party for the report, while John Holloway, Professor of Allergy and Respiratory Genetics at the University, co-wrote Chapter 3: In the beginning: protecting our future generations.

Professor Holloway explores how and why infants and young children are affected by air pollution. It says that due to the rapid pace of change which take place in utero and early childhood as children develop, the adverse effects from air pollution can have far greater influence on health than exposure of adults, as important organ systems, once their development is harmed, cannot recover resulting in life long effects on health. In particular, harmful exposures during pregnancy can modify DNA of the developing child, altering the way genes are regulated. This can not only alter development of organs (such as the lungs), leading to differences in organ function at birth, but may also lead to altered responses to further exposure to pollutants later in life.

Professor Holloway comments: “There are three major periods of vulnerability to the adverse effects of air pollution: the mother’s health during pregnancy, the development of the fetus and infancy. Everything is inextricably linked. There is no doubt that air pollution can affect the fetus, either indirectly through the health of the mother, or directly by affecting developing fetal organs and systems. These effects can have a permanent influence on growth and health throughout life. Exposure of the young child to air pollution can produce definite harm and increase the risk of disease both immediately and throughout the rest of their lives. We must act now to ensure our future generations are not put at risk.”

Professor Holgate adds: “We now know that air pollution has a substantial impact on many chronic long term conditions, increasing strokes and heart attacks in susceptible individuals. We know that air pollution adversely effects the development of the fetus, including lung development. And now there is compelling evidence that air pollution is associated with new onset asthma in children and adults. When our patients are exposed to such a clear and avoidable cause of death, illness and disability, it our duty to speak out.”

The landmark report has been led by the Royal College of Physicians (RCP) and the Royal College of Paediatrics and Child Health (RCPCH).

In relation to asthma, the report stresses the significant point that after years of debate, there is now compelling evidence that air pollution is associated with both reduced lung growth in childhood and new onset asthma in children and in adults – whilst highlighting that air pollution increases the severity of asthma for those with the disease.

In recent years the dangers of outdoor air pollution have been well documented however, the report highlights the often overlooked section of our environment – that of indoor space. Factors such as, kitchen products, faulty boilers, open fires, fly sprays and air fresheners, all of which can cause poor air quality in our homes, workspaces and schools. According to the report indoor air pollution may have caused or contributed to 99,000 deaths annually in Europe.

Although government and the World Health Organization (WHO) set ‘acceptable’ limits for various pollutants in our air, the report states that there is in fact no level of exposure that can be seen to be safe, with any exposure carrying an associated risk.

As a result, the report offers a number of major reform proposals setting out what must be done if we are to tackle the problem of air pollution.
These include:

  • Put the onus on polluters. Polluters must be required to take responsibility for harming our health. Political leaders at a local, national and EU level must introduce tougher regulations, including reliable emissions testing for cars.
  • Local authorities need to act to protect public health when air pollution levels are high. When these limits are exceeded, local authorities must have the power to close or divert roads to reduce the volume of traffic, especially near schools.
  • Monitor air pollution effectively. Air pollution monitoring by central and local government must track exposure to harmful pollutants in major urban areas and near schools. These results should then be communicated proactively to the public in a clear way that everyone can understand.
  • Quantify the relationship between indoor air pollution and health. We must strengthen our understanding of the key risk factors and effects of poor our quality in our homes, schools and workplaces. A coordinated effort is required to develop and apply any necessary policy changes.
  • Define the economic impact of air pollution. Air pollution damages not only our physical health, but also our economic wellbeing. We need further research into the economic benefits of well-designed policies to tackle it.
  • Lead by example within the NHS. The health service must no longer be a major polluter; it must lead by example and set the benchmark for clean air and safe workplaces.

The report also emphasises how the public can do their part to reduce pollutant exposure. Noting the impact collective action can have on the future levels of air pollution in our communities.

Suggestions include:

  • Trying alternatives to car travel or preferably taking the active option: bus, train, walking and cycling.
  • Aiming for energy efficiency in our homes.
  • Keeping gas appliances and solid fuel burners in good repair.
  •  Learning more about air quality and staying informed.

Other key points from the report note:

  • Estimated cost of air pollution in the UK is £20 billion annually (in Europe €240 billion)
  • A need to develop new technologies to improve air pollution monitoring.
  • More research to determine how social and economic trends are affecting air quality and its twin threat climate change.


Rising traffic congestion fuels health warning

By Cathy O’Leary – The West Australian

November 21, 2016, 1:48 pm

A world expert on airborne diseases is warning that a rapid rise in traffic congestion in Perth is fuelling air pollution and threatening the health of children.

Professor Stephen Holgate believes Western Australia is at risk of being complacent because of its clear blue skies and relative lack of smog or visible air pollution.

But among the biggest culprits of unseen air pollution are diesel and petrol fumes from cars and trucks.

The University of Southampton asthma researcher will issue a blunt warning about air pollution at the Telethon Kids Institute’s annual community lecture on November 29.

Professor Holgate worked on British research which recently linked 40,000 deaths a year to outdoor air pollution.

He said children were especially vulnerable.

The joint study by the Royal College of Physicians and the Royal College of Paediatrics and Child Health found the impact was not just on respiratory conditions, but on heart disease and diabetes.

“Negative impacts begin when a human is conceived and are at their most virulent until the age of 18,” Professor Holgate said.

“The evidence is very strong about the impact on the risk of developing allergy and asthma, but the effects are much wider than we thought.

“You don’t want to expose the next generation to chemicals that affect not just the lungs but things like brain development and the pancreas.”

Professor Holgate said the absence of smog meant people might dismiss concerns.

“It is what you can’t see that arguably presents the greatest risk because it means government and community leaders may think there is nothing to worry about,” he said.

“Congestion is the problem, when you have engines idling and giving out chemicals, and the car behind is getting the fumes from the one in front. But you can’t see it or smell it.”

It could affect urban planning, such as whether schools and childcare centres should be near busy freeways.

Kirsten Di Lazzaro said she was more mindful of avoiding car fumes since she became a mother.


Some information on asthma and air pollution from Asthma UK

Why are people with asthma more at risk from pollution?

When pollution levels are high we all breathe in harmful substances; but if you’ve got asthma you’re much more likely to feel the effects. You might notice you’re coughing or wheezing, your chest is tight, or your nose and throat feel scratchy. Pollution is more of a risk for people with asthma because:

  • Pollutants, such as the chemicals in traffic fumes, can quickly irritate the airways and trigger asthma symptoms.
  • The tiny particles found in dust, soot, and diesel fumes are small enough to get right into the lungs, causing inflammation and making your asthma symptomsworse.
  • Pollution can make you more sensitive to your usual asthma triggers (such as house dust mites, pollen, pets, moulds and fungi).

Are some people with asthma more at risk than others?

Air pollution is a risk factor for everyone with asthma but if your asthma is well managed and you rarely have symptoms you’ll be much more able to cope with the effects.

Some people with asthma need to take extra care:

  • Children and young adults with asthma are more at risk from the effects of pollution because they have faster breathing rates, and their lungs are still developing.
  • Children living in areas with high pollution are more likely to have reduced lung function as adults.
  • Older people with asthma, particularly if they have underlying COPD or another long-term condition such as heart disease may find it harder to cope with pollution.
  • People with severe asthma or asthma that’s difficult to manage may find their symptoms get worse even on low pollution days.
  • People who are exposed to pollution on a daily basis, for example because they live or work near a busy main road.