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A 17 year-long study investigated 71,362 residents living in ambient air pollution. After the follow-up, 21% of the cohort had died and notable associations were made between airpollution and increased risk of cancers, cardiac diseases, and neurological diseases (Bauleo, 2019).

Research has also been conducted to evaluate the effect of air pollution on the growth rate of children lungs. From 2014 to 2017, 21,616 school-children in China were evaluated and a dramatic decrease in lung growth was concluded (Wang, 2020). Every 10 μg/m³ increase in annual PM2.5 level (fine partriculate matter molecules) the annual forced vital capacity (FVC) growth reduced by 12.2 mL.

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Bauleo, L. et al., (2019). Long-term exposure to air pollutants from multiple sources and mortality in an industrial area: a cohort study. Occupational and Environmental Medicine, 76(1), pp. 48-57.

Channell, M., et al., (2012). Circulating Factors Induce Coronary Endothelial Cell Activation Following Exposure to Inhaled Diesel Exhaust and Nitrogen Dioxide in Humans: Evidence From a Novel Translational In Vitro Model. Toxicological Sciences, 127(1), pp.179-186.

Jiang, X. et al., (2016). Air pollution and chronic airway diseases: what should people know and do?. Journal of thoracic disease, 8(1), E31–E40.

Newell, K., et al., (2019). Household Air Pollution and Associated Health Effects in Low and Middle Income Countries. Reference Module in Biomedical Sciences.

Nurkiewicz, T. et al., (2010). Assessment of Vascular Reactivity. Comprehensive Toxicology, pp.133-148.

Dr Presneau, N (2021), Specialist Epithelia Lower Respiratory Tract [Lecture Notes]. Functional Anatomy. Available from www.learning.westminster.ac.uk. [Accessed 15 March 2021].

Raaschou-Nielsen, O. et al., (2013). Air pollution and lung cancer incidence in 17 European cohorts: prospective analyses from the European Study of Cohorts for Air Pollution Effects (ESCAPE).

Saladin, K., (2018). Human Anatomy. 6th ed. McGraw Hill.

Wang, T. et al., (2020). Association between air pollution and lung development in schoolchildren in China. J Epidemiol Community Health, 74(1), pp.792-798.

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Chronic Obstructive Pulmonary Disease (COPD): 

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Chronic Obstructive Pulmonary Disease (COPD): 

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Another potential consequence of constant air pollution is COPD. The most common prominent indicator of COPD is lung tissue inflammation. Other effects on the body are:
- the self-cleaning mechanism in the respiratory airways becomes damaged,
- it becomes easier for pathogens to attach themselves to respiratory mucus cells,
- the resistance ability of immune system is reduced.
(Jiang, 2016)

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The toxicity of air pollutants can cause cancer to develop, especially in the lungs. A study in 2013 investigated the correlation between lung cancer and ambient air pollution in European populations. A cohort of nearly 313,000 participants were spread in areas with different potential factors such as particulate matter concentrations, nitrogen oxide levels, and traffic intensity. After 8-12 years, 2095 members had developed lung cancer, especially those living in locations with more particulate matter present (Raaschou-Nielsen et al., 2013). In terms of the affect on cell types and its function, exposure to particulate matter causes endothelium-dependent arteriolar dilation to become significantly impaired or destroyed completely (Nurkiewicz et al., 2010). Particulate exposure also has links to:
- viability of alveolar macrophages with reduced phagocytosis;
- increase in inflammatory markers;
- alterations in the behavior of antigen presenting cells;
- adverse effects on surfactant and cilia function.
(Newell et al., 2019)

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Relations between Cell Function and Air Pollution-Related Illnesses

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Relations between Cell Function and Air Pollution-Related Illnesses

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Long-term exposure to air pollution is detrimental to the respiratory system and often chronic. The damage to cells affects its functionand therefore leads to illnesses. Some examples of this are described below.

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Protects the respiratory tract.

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Site where gaseous exchange occurs.

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Involved in both
air flow and gas exchange
between air and blood

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Increases surface area hence efficiency of gaseous exchange.

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Histology of the Lower Respiratory Tract

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Histology of the Lower Respiratory Tract

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The upper airways consists of the nose, pharynx and the larynx.
The nose is mainly composed of bone and hyaline cartilage (lateral and alar). The nasal cavity is lined with stratified squamous epithelium followed by ciliated psuedostratified columnar epithelium. The main features of this epithelium are many mitochondrion present, and increased surface area with about 300 cilia on each cell. Respiratory epithelium covers most of the mucosa and contains goblet cells, endocrine cells, chemosensory brush cells and basal stem cells. The lamina propria is loose areolar connective tissue and has different roles depending on which mucosa its found; in the respiratory mucosa, it contains glands which supplement the mucus produced by goblet cells. In the olfactory mucosa, the lamina propria has glands which secrete fluid to facilitate the diffusion of odor molecules. The lamina propria also contains lymphocytes to defend pathogens which spread via inhalation, and large blood vessels to warm the air for easier breathing.
Similarly in the pharynx, both pseudostratified coloumnar epithelium and stratified squamous epithelium is present. The larynx is formed by nine cartilages, one epiglottic cartilage and the rest are hylaline cartilages (Saladin, 2018).

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Lower Airways- Trachea to Pulmonary Alveoli

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Lower Airways- Trachea to Pulmonary Alveoli

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The lower airways consists of the trachea, bronchi, lungs and pleurae.
Trachea walls have 4 layers:
- Mucosa - ciliated, pseudostratified
epithelium and elastic fibre-rich
lamina propria
– Submucosa - denser connective
tissue, containing glands
– Cartilaginous layer - unique feature
- C-shaped hyaline cartilage with
gaps bridged by fibroelastic tissue
and smooth muscle
– Adventitia - binds trachea to
adjacent structures
The bronchi initally have the same structure as the trachea, however thick smooth muscle becomes circular as it replaces the cartilage, and cartilage rings become plates.
Alveoli exist between thin connective tissue surrounded by a system of capillaries. The alveolar epithelium consists of two different types of cells; 95% are thin squamous type 1 alveolar cells which line the surface of the alveoli and 5% are cuboidal type 2 alveolar cells which are scattered in the lining.
Next are the pleurae which is split into parietal and visceral layers. This creates a serous membrane covering the lungs, and allows substances to be transported (Dr Presneau, 2021).

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Structural differences between the upper and lower airway:

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Structural differences between the upper and lower airway:

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The respiratory system is categorised into two parts- the upper respiratory tract and the lower respiratory tract.