Air Pollution's Impact On Human Health And Wellbeing

Air pollution is a pressing issue that has serious toxicological impacts on human health. It is caused by a range of sources, from cigarettes to natural sources such as volcanic activity, and large-volume emissions from motor vehicles and industrial activities. The World Health Organization identifies six major air pollutants: particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead.

The effects of air pollution on human health vary from mild breathing difficulties to severe cardiovascular issues, including heart disease and stroke. Research has also linked air pollution to serious health problems, adverse birth outcomes, and even premature death.

Short-term exposure to air pollution can lead to respiratory infections and reduced lung function, while long-term exposure can cause more serious issues such as heart disease, lung cancer, respiratory diseases, and damage to the nerves, brain, kidneys, liver, and other organs.

Certain groups, such as children, the elderly, and people with existing diseases, are particularly vulnerable to the adverse health effects of air pollution.

To protect human health, it is crucial to improve air quality on a global scale and implement measures to reduce air pollution.

Respiratory issues

Air pollution has a wide range of effects on human health, including respiratory issues. Respiratory issues can range from mild breathing difficulties to more severe conditions.

Short-term exposure to air pollution can lead to respiratory infections and reduced lung function. It can also aggravate asthma in people with this condition. Long-term exposure to air pollution has been linked to serious health problems, including respiratory diseases such as emphysema and chronic bronchitis, which are forms of chronic obstructive pulmonary disease (COPD). COPD is a group of diseases that cause breathing-related difficulties, blocking the airways and making it hard for a person to breathe. According to the World Health Organization (WHO), air pollution causes 43% of COPD cases and deaths worldwide.

Particle pollutants, a major part of air pollution, have been linked to most pulmonary and cardiac-associated morbidity and mortality. Fine particle pollutants can cause premature death in people with heart and/or lung disease, including cardiac dysrhythmias, non-fatal heart attacks, aggravated asthma, and decreased lung function.

Ozone, another component of air pollution, is a well-established respiratory irritant. Short-term exposure to ozone can cause chest pain, coughing, and throat irritation, while long-term exposure can lead to decreased lung function and chronic obstructive pulmonary disease.

Sulfur dioxide, a byproduct of burning fossil fuels, can cause eye irritation and make people more vulnerable to developing respiratory tract infections. Nitrogen dioxide, present in vehicle exhaust emissions, can lead to respiratory infections, coughing, wheezing, headaches, throat irritation, chest pain, and fever.

Overall, air pollution has significant impacts on respiratory health, ranging from mild symptoms to severe and life-threatening conditions.

Cardiovascular issues

Air pollution has been linked to a variety of health issues, including severe cardiovascular problems. Cardiovascular disease is the biggest environmental risk factor for early death, causing more than 6 million premature deaths each year.

Air pollution is made up of small particles and harmful gases and particles in the air. These include:

• Particulate matter (PM10, PM2.5)
• Black carbon
• Nitrogen oxides (NO and NO2)
• Ozone
• Sulfur dioxide (SO2)

These pollutants can cause a range of cardiovascular issues, including:

• Atherosclerosis: a buildup of plaque in the coronary artery, which can affect heart health and increase the likelihood of cardiovascular events like heart attacks and strokes.
• Arteriosclerosis: exposure to air pollution and road traffic is associated with an increased risk of arteriosclerosis, as shown by premature aortic and coronary calcification.
• Myocardial infarction: short-term increases in air pollution are associated with an increased risk of myocardial infarction, stroke, and acute heart failure.
• Thrombus formation: air pollution increases coagulation factors and platelet activation, promoting thrombus formation.
• Vascular oxidative stress reaction: air pollution induces a systemic vascular oxidative stress reaction, which can lead to endothelial dysfunction, monocyte activation, and proatherogenic changes in lipoproteins, initiating plaque formation.

Who is most at risk?

While air pollution can affect anyone, some groups are more vulnerable to its cardiovascular effects. These include:

• Children
• The elderly
• People with existing diseases
• Minority and low-income communities
• Diabetics
• Smokers

Neuropsychiatric complications

Air pollution is a significant environmental health risk, especially in urban areas and developing countries. It is well-established that air pollution harms respiratory and cardiovascular health. However, there is a growing body of evidence that highlights its impact on neurological and neuropsychiatric conditions as well.

Mechanisms of Neurotoxicity

Air pollution consists of various gaseous and particulate components, such as nitrogen oxides, particulate matter, volatile organic compounds, and polycyclic aromatic hydrocarbons. These pollutants can trigger lung sensory afferents, which, in turn, activate the body's stress response systems, including the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic-adrenal-medullary (SAM) axis. Prolonged activation of these axes can lead to pathological changes, including neuroinflammation, neurotransmitter imbalances, and neuroendocrine disruptions.

Particulate matter, especially fine particles like PM2.5, can penetrate deep into the lungs and bloodstream, causing serious health risks. These fine particles have been linked to increased oxidative stress, microglial activation in the brain, and elevated pro-inflammatory cytokines, all of which contribute to neurological pathology.

Additionally, air pollution can impair the blood-brain barrier, alter neurotransmitter levels, and induce apoptosis in neuronal cells, hindering neural stem cell differentiation and brain function.

Neuropsychiatric Disorders

Anxiety and Depression

Air pollution has been linked to an increased risk of anxiety and depressive disorders. Pollutants can induce oxidative stress and neuroinflammation, leading to structural changes in the brain, particularly in regions like the hippocampus, amygdala, and prefrontal cortex, which are crucial for emotion regulation. These changes can then precipitate depressive and anxiety symptoms.

Several studies have found a correlation between air pollution exposure and increased anxiety-like behaviors in animal models. Human studies have also reported a positive association between air pollution and anxiety symptoms, especially in women.

Cognitive Decline and Neurodegenerative Diseases

Air pollution has been implicated in cognitive decline and neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Exposure to particulate matter, especially PM2.5, has been linked to cognitive deterioration and neurodegeneration due to inflammation, oxidative stress, and disruption of the blood-brain barrier.

Studies have shown that elderly adults exposed to high levels of PM exhibited significant cognitive decline, particularly those predisposed to Alzheimer's disease. Additionally, exposure to nitrogen dioxide, another prevalent air pollutant, has been associated with cognitive decline and neurodegeneration, as it can induce oxidative stress and inflammation in the brain, leading to neuronal damage.

Autism Spectrum Disorder (ASD)

There is also growing evidence of a link between air pollution and the development of Autism Spectrum Disorder (ASD). Research has shown a correlation between prenatal exposure to air pollutants and an increased risk of ASD. Anxiety is a prevalent issue among individuals with ASD, and exposure to air pollution may exacerbate these symptoms.

Air pollution poses a significant risk to neuropsychiatric health, contributing to various disorders such as anxiety, depression, cognitive decline, and neurodegenerative diseases. The intricate mechanisms by which air pollutants affect the nervous system are still being unravelled, underscoring the urgent need for policy interventions and further research to mitigate the impact of air pollution on neurological health.

Skin diseases

Skin Ageing

Air pollution can cause skin ageing, including wrinkles, pigment spots, and skin laxity. This is due to the activation of the aryl hydrocarbon receptor (AhR) pathway, which regulates the expression of genes involved in skin ageing. In addition, air pollution can deplete the skin's antioxidant molecules, such as vitamins C and E, leading to oxidative stress and subsequent skin ageing.

Inflammatory Skin Diseases

Air pollution has been linked to inflammatory skin diseases such as atopic dermatitis, eczema, acne, and psoriasis. The activation of the AhR pathway by air pollutants can induce the production of pro-inflammatory molecules and oxidative stress, which can exacerbate inflammatory skin diseases.

Skin Accessory Diseases

Air pollution has been associated with skin accessory diseases such as acne and alopecia. This is due to the activation of the AhR pathway, which can induce the production of inflammatory molecules and oxidative stress.

Immune-Related Skin Diseases

Air pollution can affect immune-related skin diseases such as cutaneous lupus erythematosus and scleroderma. This is due to the activation of the AhR pathway, which can induce inflammatory responses and oxidative stress.

Skin Tumours

Air pollution has been implicated in the development of skin tumours, including melanoma, basal cell carcinoma, and squamous cell carcinoma. This is due to the activation of the AhR pathway, which can induce the expression of genes involved in skin cancerogenesis.

Overall, air pollution can have significant effects on skin health, including the development of skin diseases and skin ageing.

Cancer

Air pollution has been linked to lung cancer, with outdoor air pollution being a major contributor to the global disease burden. While smoking is a significant cause of lung cancer, air pollution is also a risk factor and is estimated to cause hundreds of thousands of lung cancer deaths annually worldwide.

Air pollution contains a mixture of particles, including particulate matter (PM), which can enter the bloodstream and contribute to various health issues. PM includes tiny particles and substances in the air, such as dust, soot, smoke, radon, and ozone. These particles can build up in the lungs and damage DNA, changing how cells divide and leading to cancer. Additionally, air pollution can cause inflammation in the lungs, which may also contribute to cancer development.

Lung cancer is the most well-established cancer type associated with air pollution. However, research also suggests links between air pollution and increased mortality risk for other cancer types, including:

• Breast cancer
• Liver cancer
• Pancreatic cancer
• Upper digestive tract cancers
• Cancers of the accessory digestive organs, including the bile ducts, gall bladder, and pancreas

Policy Implications and Prevention

To reduce the cancer risk from air pollution, it is essential to implement measures to improve air quality. This includes reducing emissions from transportation, power generation, and industrial sources. Additionally, individuals can contribute by opting for more active modes of transportation, such as walking or cycling, instead of driving.

It is worth noting that air pollution is not the only risk factor for cancer, and factors such as diet and exercise may be more significant. However, addressing air pollution can have additional health benefits, including reducing the risk of respiratory and heart diseases.

Frequently asked questions