Air Pollution and Respiratory Health
Alysha K Afsar
UoB: 16000984
18th November 2016.
This is the draft essay handed in as part of Special Studies 0.
Word Count: 1464
Introduction
Air pollution can be defined as a combination of both, natural and manmade material in the air that we inhale.1 There are two types of pollution, outdoor pollution and indoor pollution1, as shown below in table one.
Examples of outdoor pollution
Examples of indoor pollution
Burning of fossil fuels.
Gases such as carbon monoxide.
Noxious gases such as sulphur dioxide.
House hold products and chemicals.
Smog.
Building material such as asbestos.
Tobacco smoke
Mould and pollen
It is widely recognised that air pollution impacts health in humans, outdoor pollution is one explanation for the rise of respiratory diseases.2 Epidemiology studies have shown a correlation between air pollution and decreased pulmonary functions3. Primary pollutants such as nitrogen oxides and volatile organic compounds (VOC’s) and secondary pollutants such as ozone, have been affiliated with respiratory health effects.4 Some impacts include an increase of diseases in people already diagnosed with chronic respiratory illnesses such as COPD and asthma, repeated hospital admissions and emergency visits for the underlying disease and decline in lung function.5 Even for healthy people air pollution can cause respiratory irritation, as the particles cause inflammation6.
Air pollution can have different impacts depending on the length of exposure, exposure to high levels of air pollution can lead to immediate health effects such as aggravated cardiovascular and respiratory illnesses, whereas, long term exposure to polluted air can have permanent health effects such as loss of lung capacity.7
Most air pollutants are results of human activity, such as the combustion of fossil fuels to produce energy, or the burning of waste and forests.8 To reduce the health impacts of the different pollutants, they need to be tackled at the source, to get rid of the pollutant and thus reduce its impact on health.7
The Respiratory System
The main role of the respiratory system is to provide the body with oxygen, as well as removing carbon dioxide from the body9. The system is made up of three main parts (table 2) – the airway, the lungs and the muscles of respiration.9
Component of the Respiratory system
Function
The airway (figure 1)
Carries air between the body and outside the body.
Lungs
The lungs are the main functional component of the respiratory system, they are responsible for gaseous exchange.
Muscles of respiration
They act as a pump, pushing the air in and out of the lungs during breathing.
The nasal cavity is the primary filter to pollutants, the air is inhaled through the nose, small hair and the humid area in the nose remove larger particles.10 The air then travels through the larynx, oesophagus and pharynx before reaching the trachea.10
The trachea then divides into the left and the right bronchus as shown in figure 1, the bronchus then split into smaller components known as the bronchioles, these contain the alveolus.10 The bronchi and the alveoli join to create the lungs.10 Certain smaller particulates which have made it past the nasal cavity can deposit on the wall of the trachea, bronchus or the bronchioles, most of these are removed through coughing and sneezing.10 The smallest particles can reach the alveoli which means it can take longer for them to be removed.
The impacts of Air pollution on the respiratory system
Polluting gases that are inhaled can slow down the movement of the cilia, meaning that it is harder for particles to be removed from the lungs, thus decreasing their functions.10 Air pollution in general can cause respiratory inflammation, even in healthy people.6 Children are more at risk of respiratory illnesses as they have rapidly growing and developing lungs.11 Their immune systems have not fully developed and therefore cannot fight of the foreign bodies12, the elderly are also at risk as their immune systems have slowed down13. Depending on the amount of time that an individual has been exposed to the pollutants, determines the impact on health, exposure to high levels of air pollution has immediate effects, some of which were mentioned earlier, but others include, added stress to the heart and lungs which must work harder to supply the body with oxygen.6 Cells in the respiratory system can also become damaged.6 Long term exposure, causes more permanent health impacts, such as decreased lung functions, development of diseases such as asthma, bronchitis, emphysema and possibly cancer.6
According to the World Health Organisation (WHO), air pollution is one of the main causes of death and disease worldwide.8 Indoor pollution is the cause for approximately 4.3 million deaths each year14, and an additional 3.7 million deaths each year are due to outdoor pollution15. Even at low rates of pollution, air pollution still poses a risk to health, due to the large number of people exposed to the pollutants, this means that it can cause significant death and morbidity on a global scale8. Air pollution is a worldwide concern, however, the impacts are unbalanced around the globe (figure 216), the impacts are more prevalent in developing countries8. The poor, including the populations that live in slums are more exposed to outdoor pollution8, whereas, women and children are more at risk of the exposure to indoor pollutants, if they live in a household which uses polluting fuels, such as coal, to provide heat8.
Pollutants impact the health of humans differently, depending on the pollutant itself 6. Particulate matter are the pollutants that have the most evidence for public health concern, alongside gases8. Particulate matter can be described as a complex mixture that may contain soot, smoke, metals and other materials, such as tire rubber6. Fine particulate matter can be both an indoor and an outdoor pollutant, and has the most impact on human health, compared to any other pollutant8. It can be directly emitted, for example, from smoke, or can be formed in the atmosphere due to reactions13. Small particulate matter causes the most damage6, as the particles can settle into smaller airways and alveoli in the lungs, as well as enter the blood stream8,13. Absorbed particles can damage inter alia lung function and the cardiovascular system8, due to oxidative stress and inflammation that leads to pulmonary anatomic and physiological remodelling14. Non-communicable diseases, such as COPD and cancer are due to exposure to particulate matter13. Figure 3 below shows the deaths due to different air-pollution related diseases in 201223.
Air pollution, especially from fine particulate matter has been classified by the IARC as a cause of lung cancer17. 30% of all deaths from lung cancer are a result of either outdoor or indoor pollution8,17. Other pollutants also impact the respiratory system6, for example Carbon monoxide, which is formed due to the incomplete combustion of organic materials such as wood, reduces the oxygen carrying capacity of the blood18. This in turn puts pressure on the respiratory system causing it to work harder, similar to the effect of the ground level ozone13,18. Ground level ozone which is formed from a chemical reaction between other pollutants, and sulphur dioxide, which is produced from the domestic and industrial burning of coal, both cause the airways to constrict and have to work harder to provide oxygen.18 Asbestos causes the lungs to scar, it is also a carcinogen and therefore, increases the risk of lung cancer18. VOC’s which come from substances such as paint, can cause breathing difficulties when inhaled18. Radon which is emitted from rocks that naturally contain radioactive elements, causes an increased risk of lung cancer18.
Health promotion and prevention strategies
Most pollutants are produced as a result of human activity and therefore the prevention of air-pollution related diseases, requires reducing the production of the pollutants, so that the impact is reduced8. There are different ways that air pollution can be reduced (table 3), so that in turn, the impacts on human health can be prevented or reduced19.
Technique
Impact
Using clean technologies to cook and provide heat.
Will reduce the amount of fossil fuels that are burnt and therefore reduce the cases of acute respiratory infections and chronic respiratory disease.
Tobacco smoke-free legislation.
This reduces the exposure to second hand smoke and therefore reduces respiratory infections.
Improving urban planning and urban transit.
Reduces the amount of pollutants that are emitted and thus reducing air-pollution related diseases.
An example of these techniques being a success, is Curitiba in Brazil, despite there being a five-fold population increase in the past 50 years, air pollution levels are comparatively lower than many other rapidly growing cities, and life expectancy is 2 years longer than the national average20. This is due to the fact Curitiba has invested heavily in improving its environment, by upgrading slums, setting in recycling initiatives such as “Green exchange” and a popular “bus rapid transit”, thus reducing the amount of pollutants emitted20.
Conclusion
The impacts of both outdoor and indoor pollution are very serious, when it comes to human health5. The impacts of both long and short term exposure of pollutants on health are significant, but the effects from long term exposure are much greater than those that are seen from short term exposure8. This shows that the damage to human health are not only due to the worsening of the underlying disease, but also to its development8.
Once people are removed from an area with high concentration of pollutants, the symptoms of diseases can be seen to reverse13. For example, the there is a dose-dependent relationship between human health and particulate matter, but it is shown that removal from an environment that has a high concentration of particulate matter, results in a decrease in the prevalence of air-pollution related diseases13.
As shown in Curitiba if cost-effective strategies are put into place and are followed, the levels of air pollution can be reduced and therefore, so will the impacts on health20. Clear air initiatives, environmental legislations and socioeconomic programmes including better nutrition, access to clean water and education programmes have been beneficial12.
Reference:
(1) National Institute of Environmental Health. Air Pollution. 2016. https://www.niehs.nih.gov/health/topics/agents/air-pollution. Accessed 10th October 2016.
(2) De Sario, M., Katsouyanni K., and Michelozzi P. “Climate Change, Extreme Weather Events, Air Pollution and Respiratory Health In Europe”. Eur Respir J 42.3 (2013): 826-843.
(3) Prottasan, P. et al. “Association Between Fractional Exhaled Nitric Oxide and Asthma Control”. Journal of Allergy and Clinical Immunology 2011; 127:
(4) Ayres, J. G. et al. “Climate Change and Respiratory Disease: European Respiratory Society Position Statement”. European Respiratory Journal 2009; 34: 295-302.
(5) Riedl, Marc A. “The Effect of Air Pollution On Asthma and Allergy”. Current Allergy and Asthma Reports 2008; 8: 139-146.
(6) Sacramento Metropolitan. Air Quality Information For The Sacramento Region. 2016. http://sparetheair.com/health.cfm?page=healthspecific#healthspecific. Accessed 14th October 2016.
(7) Granier C, Bessagnet B, Bond T et al. “Evolution of Anthropogenic And Biomass Burning Emissions Of Air Pollutants At Global And Regional Scales During The 1980–2010 Period”. Climatic Change 109.1-2 (2011): 163-190.
(8) WHO, 68th World Health Assembly. Addressing the health impacts of air pollution, 10th April 2015. Accessed 1st November 2016.
(9) Ozkaynak, Haluk. “ESTIMATING HEALTH EFFECTS FROM EXPOSURES TO OUTDOOR AND INDOOR SOURCES OF AIR POLLUTION”. Epidemiology 2004; 15: S16.
(10) Maroni, M. “Health Effects Of Indoor Air Pollutants And Their Mitigation And Control”. Radiation Protection Dosimetry 1998;78: 27-32.
(11) Liu, Ling et al. “Acute Effects Of Air Pollution On Pulmonary Function, Airway Inflammation, And Oxidative Stress In Asthmatic Children”. Environ Health Perspect 2008; 117: 668-674.
(12) Ward, Jeremy P. T, Jane Ward, and Richard M Leach. The Respiratory System at a Glance. Hoboken: John Wiley & Sons, 2011.
(13) Anderson, Jonathan O., Josef G. Thundiyil, and Andrew Stolbach. “Clearing The Air: A Review Of The Effects Of Particulate Matter Air Pollution On Human Health”. Journal of Medical Toxicology 2011; 8: 166-175
(14) WHO. Burden of disease from Household air pollution in 2012. 2014. http://www.who.int/indoorair/en Accessed 1st November 2016.
(15) WHO. Burden of disease from outdoor air pollution in 2012. 2014. http://www.who.int/outdoorair/en Accessed 1st November 2016.
(16) WHO. Health topics. http://www.who.int/phe/health_topics/outdoorair/databases/FINAL_HAP_AAP_BoD_24March2014.pdf?ua=1 Accessed 2nd November 2016.
(17) Straif K, Cohen A, Samet J. Air Pollution and cancer. IARC Scientific publication No 161. Lyon, France; International Agency for Research on Cancer, http://www.iarc.fr/en/publication/books/sp161/index.php Accessed 2nd November 2016.
(18) Stratford-on-district council. Air Pollutants and their effects. Stratford, UK. http://www.stratford.gov.uk/community/air-pollutants-and-their-effects.cfm 2016. Accessed 3rd November 2016.
(19) WHO. Deaths attributable to unhealthy environments. http://www.who.int/mediacentre/news/releases/2016/deaths-attributable-to-unhealthy-environments/en Accessed 3rd November 2016.
(20) WHO. Outdoor air quality and health. http://www.who.int/mediacentre/factsheets/fs313/en/ Accessed 3rd November 2016.