Air Pollution Theses: Health Edition 

The below article talks about several theses that have been proposed and proven by researchers all around the world on the effects of air pollution on human health. The article aims to provide a holistic view of air pollution and its effects on health, as well as some frequently asked questions about the same. 

Does air pollution have an impact on human health?

Yes, air pollution definitely has an impact on human health. These can be temporary effects such as nausea, dizziness, breathlessness, to long-term and chronic diseases such as respiratory issues, cardiovascular diseases, chronic obstructive pulmonary disorders, cancer, etc. There have been several studies conducted over the years to identify the impacts of air pollution, and the below article aims to cover a few of these studies.  

Environmental and Health Impacts of Air Pollution (Manisalidis I. et.al., 2020)

The article has aimed to study the impacts of air pollution on public and individual health due to the observed trends of increasing morbidity and mortality. The article recognizes that there are varying kinds of pollutants that have varying impacts on human health depending on the pollutant’s physical, chemical, and biological characteristics. The subsequent study has reported that people exposed to higher concentrations of air pollutants experience various kinds of diseases in varying degrees of severity, and are generally categorized into short-term effects and long-term effects on health. 

Short-term effects are temporary and can range anywhere from minor discomforts such as irritation of the eyes, nose, skin, and throat, wheezing, coughing, tightness of the chest, breathlessness or shortness of breath, and breathing difficulties, to more serious situations such as a diagnosis of asthma, bronchitis, cardiovascular diseases, etc. Short-term exposure could also cause temporary discomforts such as nausea, headaches, and dizziness. These symptoms are usually aggravated due to prolonged exposure and threaten our neurological, respiratory, and reproductive systems; and can cause severe diseases leading to death. 

Particulate matter, dust, benzene, ozone, etc. can cause serious damage to respiratory systems and is particularly harmful to already vulnerable populations such as people with existing illnesses, senior citizens, kids, etc. Long-term effects have been found in such populations at higher rates, and it has been found that there are voice alterations following acute exposure to pollutants. There is also an increase in Chronic Obstructive Pulmonary Disease (COPD) cases induced by increasing air pollution and exposure from sources such as vehicular emissions during traffic, industrial air pollution, fuel combustion emissions, etc. leading to a pattern of increased mortality and morbidity. 

Cardiovascular effects noticed as induced by air pollution were as follows: changes in characteristics of blood cells due to exposure to pollutants could affect cardiac activities, coronary arteriosclerosis was reported following long-term exposure to traffic emissions, short-term exposure caused higher rates of diagnosis of hypertension, strokes, myocardial infractions, heart insufficiencies, etc. Long-term exposure to nitrogen oxide has been found to trigger ventricle hypertrophy as well. 

Neurological effects following exposure to air pollution were observed in adults and kids. Psychological effects such as autism, retinopathy, constricted fetal growth, low birth weights, etc. seemed to show increased incidence following long-term exposure. Traffic-related pollutants such as volatile organic compounds, poly-aromatic hydrocarbons, oxides, and particulate matter, have been found to cause pigmented spots on human skin and these pollutants are able to be absorbed into the skin contributing to premature skin aging, psoriasis, acne, urticaria, eczema, and atopic dermatitis. The diseases were found to be triggered by exposure to oxides and photochemical smoke; and exposure to particulate matter and cigarette smoke has been found to accelerate the symptoms of akin aging, skin spots, dyschromia, and wrinkles. Pollutants have also been found to trigger skin cancer in many. The study has also found that the eyes would be affected by air pollution and specific air pollutants causing dry eyes, irritation, retinopathy, etc. 

Ambient Air Quality and Human Health in India (Conibear L. A., 2018 December)

The study recognizes that air pollution in India is a leading health risk amongst citizens in the country. India is found to contribute approximately 25 – 30% of the global disease burden as a result of air pollution while contributing to 18% of the global population. There are various pollutants that lead to varying effects on human health, in varying degrees of severity. 

The health effects of PM2.5 depend on concentrations and the time period of exposure. Long-term exposure has larger and more long-term effects including cardiovascular mortality and morbidity, respiratory distress, reproductive and development issues, etc. Short-term exposure has been found to cause similar effects of lower degrees of severity and is more likely to cause respiratory discomfort over other effects. Vulnerable populations include those with underlying conditions of cardiovascular and respiratory illnesses, senior citizens, children with respiratory illnesses, vulnerable and marginalized communities in the lower socio-economic bracket, and thus may not have access to health services or other facilities, etc. 

Long-term exposure to PM2.5 has been found to cause various diseases including Ischaemic heart disease (IHD), cerebrovascular disease (CEV), atherosclerosis, coagulation, hypertension, and vascular reactivity, Chronic obstructive pulmonary disease (COPD), lower respiratory infection (LRI), impaired lung functions and lung growth, severe respiratory difficulties, asthma, altered pulmonary functioning, mild to severe inflammation, oxidative responses, immune suppression, histopathological changes, exacerbated allergic responses, low birth weight, infant mortality, lung cancer (LC), etc. Although with limited evidence, it has been also found to trigger bladder cancer, lung adenoma, enhanced frequencies of chromosome aberrations and micronuclei in lymphocytes, genetic and DNA damage, genetic mutations, altered gene expression, and DNA methylation.

Short-term exposure to PM2.5 has been found to cause increased rates of hospital admissions for Ischaemic heart disease (IHD), cardiovascular diseases, COPD, respiratory infections, asthma, altered pulmonary function, pulmonary inflammation, oxidative responses, exacerbated allergic responses, allergic sensitization, and airway hyper-responsiveness, altered vasomotor function, altered vessel tone, microvascular reactivity, myocardial ischemia (reduced blood flow), heart rate variability, systemic oxidative stress, altered blood pressure, blood coagulation, and systemic inflammation.

Long-term exposure to ozone has been found to trigger COPD, respiratory symptoms, new-onset asthma, respiratory mortality, increased vascular disease, decreased sperm concentration, reduced birth weight, restricted fetal growth, alterations in neurotransmitters, motor activity, memory, sleep, and neurodegeneration. Short-term exposure to ozone has led to increased hospital admissions rates for respiratory infections, COPD, asthma, respiratory tract inflammation, altered lung function, inflammatory responses, epithelial permeability, airway hyperresponsiveness, and host defense impairment. There also seems to impact on the autonomic nervous system, oxidative stress, incidence of inflammation, decreased cardiac function, altered heart rate, enhanced ischemia injury, and disrupted vascular reactivity, alterations in neurotransmitters, motor activity, memory, sleep, and neurodegeneration.

Below is a diagram from the study which provides an overview of the diseases, conditions, and biomarkers that could be potentially negatively affected by air pollution. 

Effects of air pollution on health: A narrative review (Mannucci P. M. et.al., 2015)

All airborne pollutants contributing to air pollution have different impacts on human health depending on the degree of concentration and time period of exposure. However, the most severe effects have been commonly attributed to the exposure due to particulate matter. This is so because these particulate matters have the capability to enter the respiratory system and damage the respiratory system. During respiratory processes, particulate matter is retained in the nasal cavities and the upper airways, whereas smaller sizes of these pollutants are able to penetrate deeper into the lung tissue, and eventually into the bloodstream. 

There are increased rates of mortality associated with particulate matter exposure, be it long-term or short-term. Short-term exposure and its effects depend on the concentrations of the pollutants daily, whereas long-term exposure looks at the time period of exposure at certain concentrations. There are increased risks associated with health effects as the time period of exposure or concentration of pollutants increases. These increases in the risks have been found most commonly in Southeast Asian countries, especially China and India. A Havard study conducted between 1974 to 2009, found that there is a 14% increased risk of mortality due to the effects of air pollution. Similarly, there are several studies that have found a significant correlation between increased incidences of diseases to air pollution. 

There are also various data that confirm a relationship between increased air pollution and the acceleration of allergic diseases such as eczema or rhinitis. Similarly, diseases such as diabetes and its cognitive effects have been found to be exacerbated due to prolonged exposure to air pollution. Studies have also found that there is a significant relationship between air pollution and gestation, and particularly there are increased risks to the pregnant individual and the child. Air pollution exposure during pregnancy has been found to lead to lower birth weights, increased incidence of stillbirths, delayed psychomotor development in childhood, etc. Further studies conducted in relation to air pollution at a household level, found an increased rate of incidence in skin and lung cancer and air pollution. Household air pollution was found to be an element of increased vulnerability that led to cancer in these individuals. Other cancers that could be triggered by air pollution include those of the cervix and upper aero-digestive tract. 

Frequently Asked Questions (FAQs): Are there any health impacts due to air pollution?

Does wearing a scarf or a damp cloth over my nose and mouth provide the same protection as a mask does during days with severe air pollution?

No, there is a wide variety of scarves, fabrics, etc. that claim to protect the user from toxic airborne pollutants. However, these are only mostly effective with respect to avoiding larger droplets or disease-causing particles like droplets from a sneeze or cough. They are not capable of providing the level of filtration and protection as a mask, as these materials will allow through tiny infected aerosol particles and fine/ coarse air pollutants into your respiratory system. 

Can poor air quality affect your pregnancy?

Unfortunately yes, poor air quality can have an impact on your pregnancy and can instigate long-term health conditions in the child or the parent. Poor air quality has been found to cause low birth weight, stillbirth, pre-term labor, autism, obesity, fertility issues, developmental disabilities amongst other health hazards. 

There are various sources of exposure and pregnant individuals need to take adequate measures to reduce the impact of air pollution on their health as well as the health of the developing child. 

Other FAQs about Air Quality that you may be interested in.

Air Pollution caused by Factories

Atmospheric Pressure: What do you need to know?

Advantages and Disadvantages of Air Pollution

References 

Conibear L. A. (2018 December). Ambient Air Quality and Human Health in India. Institute for Climate and Atmospheric Science. School of Earth and Environment. Faculty of Environment. The University of Leeds. pp. 45 – 55. Viewed on 12-21-2021. https://etheses.whiterose.ac.uk/22488/1/Conibear_LA_Chemical-and-Process-Engineering_PhD_2018.pdf 

Manisalidis I., Stavropoulou E., Stavropoulos A., & Bezirtzoglou E. (2020, February 20). Environmental and Health Impacts of Air Pollution. Frontiers in Public Health. 8(14). Viewed on 12-21-2021. https://www.frontiersin.org/articles/10.3389/fpubh.2020.00014/full 

Mannucci P. M., Harari S., Martinelli I., & Franchini M. (2015, March 24). Effects of air pollution on health: a narrative review. Internal and Emergency Medicine. 10(6). pp. 657 – 662. Viewed on 12-21-2021. https://sci-hub.hkvisa.net/10.1007/s11739-015-1276-7 

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