Health Effects of Air Pollution: From Head to Toe

Health Effects of Air Pollution: From Head to Toe

At a first glance you’d be forgiven for thinking that air pollution only affects your lungs and heart; but the harmful effects of air pollution go way beyond that. In fact, recent studies found surprisingly strong relations between air pollution and several other systems in the human body.

 

Here is a detailed layout of what air pollution can do to different parts of your body:

Respiratory System

The respiratory system is always the first victim of air pollution because particulates and gaseous pollutants immediately start accumulating in the airways. Over-accumulation of pollutants, such as sulfur dioxide, ozone, nitrogen oxide, and PM2.5, weakens your respiratory defenses, making you more vulnerable to complications in the throat and the lungs [1]. 

Here are some examples:

Symptoms in the upper respiratory system include nasal congestion, sinusitis, and irritation in the throat [1]. Accumulation in the lungs complicates matters by damaging the lung membrane and causing airway inflammation. Studies linked this increase to exacerbation of asthma, chronic obstructive pulmonary disease (COPD), bronchitis, allergies, and lung cancer. For example, between 1990 and 2017, air pollution was associated with 40% of COPD, 35.6% of lung infections, and 25.8% of lung cancer hospitalizations in China alone [4].

You might wonder why the immune system falls short of removing these pollutants. Under normal conditions, the respiratory system produces mucus to capture and expel some of the pollutants and germs [2]. However, continuous exposure to airborne particles punctures the protective membrane and hinders the cleansing. In turn, more pollutants can bypass the respiratory defense systems and congregate in the tissue [3]. 


Cardiovascular System

Increasing evidence shows that air pollution can take the hardest toll on blood vessels and the heart. In particular, the entrance of CO, NOx, and PM2.5 into our bloodstream has serious consequences.

More specifically, these particles damage the inner walls of blood vessels, stiffening, and narrowing them. Experimental data from National Ambient Air Quality Standards found that long-term exposure to particulate matter and nitrogen oxides caused a buildup of calcium in the coronary artery. Such accumulation restricts blood flow, increasing blood pressure, and clotting [5]. 

Further evidence demonstrated how pollutants in the bloodstream affected the electrical and physical structure of the heart, resulting in heart arrhythmia, cardiac arrest, and heart failure [6].

The majority of heart diseases in areas with bad air quality are linked to air pollution. For example, statistics from the UK's polluted areas directly linked 36,000 cardiac death cases to air pollution each year.

Nervous System

Emerging evidence started to reveal direct and indirect pathways of air pollution leading to cognitive abnormalities, neural death, and dementia. 

Here is a summary:

The direct mechanism refers to ultrafine particles, UFP or PM0.1, entering the brain through the olfactory nerves in the nose. These nerves are responsible for the direct transport of very small particles to the brain. In animal tests, exposure to UFP induced the number of toxic molecules in the brain, damaging the neurons. The animals also exhibited behavior that reflected characteristics of autism [7]. 

Researchers conducted studies on populations in Mexico City, one of the most polluted cities in the world. Autopsy reports on 186 people between the ages of 0-27 showed brain abnormalities, such as agglomeration of toxins that accelerated neural death [8].

The indirect effects on CNS stem from cardiovascular diseases. More specifically, the dysfunction of circulation hinders the delivery of nutrients and minerals, causing premature aging of the brain. Studies showed that exposure to PM2.5 and NO2 increased the risk of dementia by 10% and 30%, while air pollution-related stroke accounted for 50% of dementia cases [9].

Bones 

With emerging evidence, air pollution is now considered one of the main contributors to osteoporosis, a skeletal abnormality that weakens the bones. When particulate matter and carbon monoxide accumulate in the bone marrow, they decrease the vitamin D necessary for bone strength. These pollutants also slow down the regeneration of our bones [10]. 

Further research revealed that air pollutants even reduced the calcium levels in our bones, making them weaker and more brittle. A complementary study tested this theory on 700,000 Medicare beneficiaries found a 4-7% annual increase in osteoporosis-related hospital admissions, especially in low-income areas near busy road networks. This annual increase reached over 20% among people above the age of 46, indicating the vulnerability of elderly people [11]. 

Reproductive System

The effects of pollution in the air expand into future generations by negatively impacting fertility.

A recent study measured the secretion of anti-Mullerian hormones, responsible for the production of healthy eggs, in women with different exposure levels to CO and NOx. The hormone levels were much lower in women with exposure to the highest air pollution level, meaning they had fewer viable eggs [12].

As for male fertility, preliminary results indicate that PM2.5 can change sperm structure and reduce sperm count [13].


Digestive System

The effects of air pollution on our digestive system are also life-threatening, as fine particles and soot can leave long-term damage to our guts. According to recent studies, when PM2.5 reaches our gut, it brings down its guard by killing beneficial bacteria and puncturing the protective membrane [14]. 

The halted immune response in the gut can lead to a variety of bowel diseases. Several case studies showed that air pollution triggered Crohn's disease, ulcerative colitis, and appendicitis [14]. 

Muscular System

The relation between air pollution and the muscular system was recently brought to attention through case studies.

A study in Taiwan conducted on the elderly found strong evidence suggesting a strong correlation between chronic exposure to PM2.5 and reduced skeletal muscle mass/increased body fat mass [15]. Another study from Brazil found that babies had 13 times higher risk of developing muscular inflammation when the mothers smoked during the pregnancy [16].

Skin, Hair, and Eyes

Our skin, hair, and eyes get their fair share of health complications. 

Harmful air particles like oxides, ozone, VOC, and particulate matter can damage the skin in several ways. Large particles accumulate on the outer layer, clogging our pores to trigger acne and brown spots. Smaller particles, especially PM0.1, can delve deeper and impair the skin barrier, making it susceptible to aging, inflammation, and skin cancer [17].

Research from last year revealed another mechanism, where PM infiltrated our follicles and inhibited the expression of beta-catenin, a protein responsible for hair growth. This study strongly supports how air pollution accelerates hair loss [18].

Contact with airborne particles has both a direct and indirect impact on the eyes. Not only do nitrogen oxide and ground-level ozone irritate the eye, but they also trigger dry eye disorder in the long run by reducing tear production [19]. Besides, particles in our bloodstream can reach and damage the small veins in our eyes, resulting in glaucoma and even blindness [20].

 

Find out about the six enemies of your health floating through the air:

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An air purifier with a HEPA filter with activated carbon could shield you from gaseous pollution and particulates. What if we told you that you could wear it around your nose and take it everywhere with you? The cutting-edge technology of Nosy X is ready to bring it to life. Find out more:

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[1] Shusterman, Dennis. "The effects of air pollutants and irritants on the upper airway." Proceedings of the American Thoracic Society 8.1 (2011): 101-105.

[2] Beule, Achim G. "Physiology and pathophysiology of respiratory mucosa of the nose and the paranasal sinuses." GMS current topics in otorhinolaryngology, head, and neck surgery 9 (2010).

[3] De Grove, K. C., et al. "Insights in particulate matter‐induced allergic airway inflammation: focus on the epithelium." Clinical & Experimental Allergy 48.7 (2018): 773-786.

[4] Uysal, Nevin, and Ralph M. Schapira. "Effects of ozone on lung function and lung diseases." Current opinion in pulmonary medicine 9.2 (2003): 144-150.

[5] Kaufman, Joel D., et al. "Association between air pollution and coronary artery calcification within six metropolitan areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): a longitudinal cohort study." The Lancet 388.10045 (2016): 696-704.

[6] Franklin, Barry A., Robert Brook, and C. Arden Pope III. "Air pollution and cardiovascular disease." Current problems in cardiology 40.5 (2015): 207-238.

[7] Allen JL, Oberdorster G, Morris-Schaffer K, Wong C, Klocke C, Sobolewski M, Conrad K, Mayer-Proschel M, Cory-Slechta DA. Developmental neurotoxicity of inhaled ambient ultrafine particle air pollution: Parallels with neuropathological and behavioral features of autism and other neurodevelopmental disorders. Neurotoxicology. 2017 Mar;59:140-154. Epub 2015 Dec 22

[8] Calderón-Garcidueñas L, González-Maciel A, Reynoso-Robles R, Kulesza RJ, Mukherjee PS, Torres-Jardón R, Rönkkö T, Doty RL. Alzheimer's disease and alpha-synuclein pathology in the olfactory bulbs of infants, children, teens, and adults ≤ 40 years in Metropolitan Mexico City. APOE4 carriers at higher risk of suicide accelerate their olfactory bulb pathology. Environ Res. 2018 Oct;166:348-362. Epub 2018 Jun 20 PubMed.

[9] Chen H, Kwong JC, Copes R, Hystad P, van Donkelaar A, Tu K, Brook JR, Goldberg MS, Martin RV, Murray BJ, Wilton AS, Kopp A, Burnett RT. Exposure to ambient air pollution and the incidence of dementia: A population-based cohort study. Environ Int. 2017 Nov;108:271-277. Epub 2017 Sep 13 PubMed.

[10] Feizabad, Elham, et al. "Impact of air pollution on vitamin D deficiency and bone health in adolescents." Archives of osteoporosis 12.1 (2017): 34.

[11] Chang, Kuang-Hsi, et al. "Exposure to air pollution increases the risk of osteoporosis: a nationwide longitudinal study." Medicine 94.17 (2015).

[12] Conforti, Alessandro, et al. "Air pollution and female fertility: a systematic review of the literature." Reproductive Biology and Endocrinology 16.1 (2018): 117.

[13] Hansen, Craig, et al. "The effect of ambient air pollution on sperm quality." Environmental health perspectives 118.2 (2010): 203-209.

[14] Salim, Saad Y et al. “Air pollution effects on the gut microbiota: a link between exposure and inflammatory disease.” Gut microbes vol. 5,2 (2014): 215-9. doi:10.4161/gmic.27251

[15] Chen, Chi-Hsien et al. “Effects of PM2.5 on Skeletal Muscle Mass and Body Fat Mass of the Elderly in Taipei, Taiwan.” Scientific Reports vol. 9,1 11176. 1 Aug. 2019, doi:10.1038/s41598-019-47576-9

[16] Orione, Maria Angélica M., et al. "Risk factors for juvenile dermatomyositis: exposure to tobacco and air pollutants during pregnancy." Arthritis Care & Research 66.10 (2014): 1571-1575.

[17] Mancebo, S E, and S Q Wang. “Recognizing the impact of ambient air pollution on skin health.” Journal of the European Academy of Dermatology and Venereology: JEADV vol. 29,12 (2015): 2326-32. doi:10.1111/jdv.13250

[18] Kim, Kyung Eun, Daeho Cho, and Hyun Jeong Park. "Air pollution and skin diseases: Adverse effects of airborne particulate matter on various skin diseases." Life sciences 152 (2016): 126-134.

[19] Gupta, Suresh K., et al. "Subclinically dry eyes in urban Delhi: an impact of air pollution?." Ophthalmologica 216.5 (2002): 368-371.

[20] Wang, Wei, et al. "Epidemiological variations and trends in the health burden of glaucoma worldwide." Acta ophthalmologica 97.3 (2019): e349-e355.






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