In today’s podcast Erica and John speak to Mustafa Abbas. Mustafa told us all about being the coordinator of Medsin’s Healthy Planet Campaign (sign the pledge) as well as being the new Vice President for Branches. He also was one of the authors on the fantastic (and enormous) report that was published recently in The Lancet on the links between climate change and health – a busy chap! So we’re really pleased that he managed to squeeze us in for a chat…listen in here.

Kate Leyland writes about the effect of air pollution on health, an article inspired by her recent intercalated year in Pharmacology completing a lab project on the effect of diesel exhaust particulate on the cardiovascular system.

Each year we take approximately 10 million breaths.  Breathing contaminated air allows toxic substances to enter the body and produce harmful effects. Clean air is therefore a fundamental precondition of health. Worldwide, the World Health Organisation reports that air pollution is responsible for an estimated 2 million premature deaths per year.(1)  Understanding the nature and magnitude of the effects of air pollutants on health is essential for developing policies to reduce their harm. After highlighting some causes and consequences of air pollution, I will explain why it is such an important global health problem, and discuss some measures for tackling it.

Air pollution contains a mixture of noxious gases, volatile organic liquids, and particulate matter. Pollutants cause pathology by different mechanisms. In the respiratory system for example: sulphur dioxide causes broncho-constriction; nitrogen dioxide damages the epithelium lining of the airways; and ozone decreases lung cell function. Combinations of pollutants can have additive or synergistic effects. In the cardiovascular system, carbon monoxide decreases the oxygen carrying capacity of blood, whereas diesel exhaust particulate impairs vascular function.(2)  It is thought that particles in air pollution do not just affect the lungs, however the mechanism for their impact on other organs is yet to be fully elucidated. The traditional view is that inhaled pollutants provoke an inflammatory response in the lung, which causes release of prothrombotic and inflammatory cytokines into the circulation.(3)  These inflammatory mediators result in pathological mechanisms such as thrombosis. Newer hypotheses incorporate evidence that inhaled particles can translocate across the alveolar wall, to enter the systemic circulation and cause direct systemic effects.(4)

Whether acute or chronic, exposure to air pollution is associated with adverse health effects. Acute exposure can cause symptoms including headache, nausea, and irritation of the eyes, nose, and throat. It can also increase prevalence of upper respiratory tract infections, such as bronchitis and pneumonia, and aggravate existing respiratory conditions, such as asthma and emphysema. There are clear associations between daily increases in air pollution and certain health outcomes, such as evidence of increased hospital admissions and premature deaths due to acute respiratory attacks.(5)  Epidemiological evidence shows that chronically high levels of air pollution may promote lung cancer(6), and myocardial infarction.(7)  Newer evidence suggests that long-term air pollution exposure may also result in damage to the brain, nerves(8), liver(9), and kidneys.(10)

Although some pollutants are naturally produced, we are responsible for a large proportion of them. Fossil fuel combustion is a major source. Power stations, factories, vehicles, offices and even our homes contribute to air pollution. Age, general health, lifestyle factors, and location influence susceptibility to the health effects of air pollution. In developed countries, people in lower socioeconomic groups are likely to live in areas, such as near main roads, where they are exposed to greater quantities of air pollution at higher concentrations. Their health is also likely to be compromised already, due to factors such as poor nutrition and lack of access to good quality medical care. As a result, they have a disproportionate disease burden compared to people in higher socioeconomic groups. The burden is even greater for people in developing countries, who bear more than half of the global ill health arising from air pollution.(1)  A large proportion of this air pollution is created by growing numbers of vehicles, often poorly maintained, which use low quality fuel and burn it inefficiently.

Recognizing air pollution as an important global health issue is fundamental to tackling it. Solving the problem also requires action from public authorities at local, national, and international levels. Health, housing, energy, and transport initiatives can all play a role in reducing air pollution. In certain parts of the world, regulations and measures have been introduced to achieve this. For example, since 2005, a 20 km bus rapid-transit system has been operating in Mexico City. It transports 263,000 people per day and exposes them to fifty percent less carbon monoxide, benzene, and particulate matter than older buses.(11)  Despite such schemes, air pollution is still a major cause of morbidity and mortality. In addition to government legislation leading to reduced air pollution levels, many people making small changes, such as using public transport instead of driving private vehicles, can make a difference.

The World Health Organisation estimates that a quarter of the world’s population is exposed to unhealthy concentrations of air pollutants.(1) Air pollution has a variety of sources, with different health consequences. Acute or chronic exposure is harmful, and the concentration of pollutants also influences the extent of damage. Measures have been taken to reduce the global health burden of air pollution, but there is considerable room for improvement. Perhaps a fresh outlook is needed to fuel future progress.

Kate Leyland is a medical student at the University of Edinburgh, Scotland.

K.A.Leyland@sms.ed.ac.uk

References

(1) Air quality and health. August 2008; http://www.who.int/mediacentre/factsheets/fs313/en/index.html [accessed Sep 6]

(2) Air pollution and health. October 2002; http://www.ncbi.nlm.nih.gov/pubmed/12401268 [accessed Sep 6]

(3) Seaton, A., Soutar, A., Crawford, V., Elton, R., McNerlan, S., Cherrie, J., Watt, M., Agius, R., and Stout, R. (1999a). Particulate air pollution and the blood. Thorax 54 (11), 1027-1032

(4) Nemmar, A., Hoet, P. H., Vanquickenborne, B., Dinsdale, D., Thomeer, M., Hoylaerts, M. F., Vanbilloen, H., Mortelmans, L., and Nemery, B. (2002). Passage of inhaled particles into the blood circulation in humans. Circulation 105(4), 411-414

(5) Air pollution and daily hospital admissions in metropolitan Los Angeles. May 2000; http://www.ncbi.nlm.nih.gov/pubmed/10811569 [accessed Sep 6]

(6) Air pollution increases lung cancer risk. March 2004; http://www.pulmonaryreviews.com/mar04/pr_mar04_pollutionlung.html [accessed Sep 6]

(7) Air pollution and cardiovascular injury. August 2008; http://content.onlinejacc.org/cgi/content/full/j.jacc.2008.05.029v1 [accessed Sep 6]

(8) Long-term air pollution exposure is associated with neuroinflammation, an altered innate immune response, disruption of the blood-brain barrier, ultrafine particulate deposition, and accumulation of amyloid beta-42 and alpha-synuclein in children and young adults. March 2008; http://www.ncbi.nlm.nih.gov/pubmed/18349428?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum [accessed Sep 6]

(9) Noninvasive assessment of liver detoxification capacity of children, observed in children from heavily polluted industrial and clean control areas, together with assessments of air pollution and chloro-organic body burden. April 2004; http://www.ncbi.nlm.nih.gov/pubmed/15037995?ordinalpos=13&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum [accessed Sep 6]

(10) Health and environment. May 2008; http://www.epa.gov/air/lead/health.html [accessed Sep 6]

(11) The Benefits and Costs of a Bus Rapid Transit System in Mexico City. May 2008; http://www.epa.gov/integenv/pdf/mexico/Metrobus%20Mexico%20Phase%20III.pdf [accessed Sep 6]

Zaid Hussain Khan writes on one of the specific impacts climate change will have on public health. 

Global warming or more specifically the ‘greenhouse effect’ refers to the trapping of solar heat by greenhouses gases such as methane, resulting in increased global temperatures. (1) Emission of greenhouse gases has increased significantly since the industrial revolution (2) and is largely anthropogenic, that is, caused by human activity. For example, growing demand for energy has amplified concentrations of CO₂, a major greenhouse gas, in the atmosphere from the burning of fossil fuels. With increased concentrations of greenhouse gases, global temperatures have risen and continue to rise; this has lead scientists to fear, rightly, the long term effects of such climate change. One of the major effects forecasted is an increase in the incidence of infectious diseases. (3) A key factor affecting the spread of infectious disease is climatic conditions, (4) as many infectious diseases rely on vector organisms for transmission. (5) These organisms are sensitive to environmental changes and therefore may be affected by global warming. (more…)

 Sarah Walpole discusses what the medical community can do and also interviews the right honourable Hilary Benn MP, Secretary of State for the UK’s Department for the Environment, Food and Rural Affairs

Climate change is, and will increasingly be, the cause of major and widespread health problems. These include trauma following natural disasters, malnutrition where crop yields are reduced, and infection due to the spread of diseases and disease vectors.

Scientists have found that there is a “tipping point” at which major destabilisation will occur, with catastrophic effects, such as major natural disasters. To avoid reaching the tipping point and prevent the major health consequences, global emissions must peak and begin to fall by 2015 (1) which is no easy target. (more…)

  Professor Hugh Montgomery is an intensive care consultant at University College Hospital London and directs the Institute of Human Health and Performance at University College London, but the way he sees it, the biggest threat to health is something that won’t be touched by these medical endeavours as Sarah Walpole finds out

This year, Professor Hugh Montgomery will be giving the Royal Institution Christmas lectures, which are about the body and the physiology of survival. “It’s theatre as much as lecturing”, and Hugh says that it may well be “the most difficult thing [he's] done”.

It’s not Hugh’s first delve into the world of entertainment though, as a film that he wrote is currently being produced for Hollywood. When given the opportunity to write a piece for the big screen, Hugh wrote this medical thriller, “Reputation and Control”, in six weeks. He has also written two novels for families (”The Voyage of the Arctic Term” and “Cloudsailors“). His latest is ‘The Genie in the Bottle- about which more later. (more…)

Sarah Walpole interviews Alex Rosen for his organisation’s views on climate change

Alex Rosen

Alex Rosen is a Paediatrician working in Germany, and a member of International Physicians for the Prevention of Nuclear War (IPPNW), an organisation which is committed to bringing a public health perspective to the debate surrounding nuclear war. IPPNW recognises the detrimental health effects of nuclear war, and is committed to preventing nuclear war and abolishing nuclear weapons.

Dr Rosen explains that IPPNW sees resource use and climate change as root causes of conflict, and argues strongly that doctors have an important role in addressing environmental issues to protect health.

(more…)