Pollution's Impact: Human Cells Under Attack

Air pollution is a public health emergency, with over 90% of the global population enduring toxic outdoor air. It is a silent killer, affecting every organ and virtually every cell in the human body.

The main reason for the far-reaching damage from air pollution is systemic inflammation. When inhaled, pollutants cause irritation, inflammation and damage to the lining of the respiratory tract. The immune system's response to the particles causes the release of enzymes and acids, which spread into the body, affecting the brain, the kidneys, the pancreas and so forth.

The harmful effects of air pollution include:

- Strokes

- Heart disease

- Lung cancer

- Asthma

- Chronic laryngitis

- Dementia

- Reduced intelligence

- Eye problems

- Skin ageing

- Kidney cancer

- Bladder cancer

- Diabetes

- Crohn's disease

- Fatty liver disease

- Reduced fertility

- Miscarriage

- Low birthweight

- Infant health problems

Air pollution can cause inflammation, which can spread throughout the body

Air pollution is a mix of gas and particles such as soot and smoke. The particles in the air are what affect global health. These particles are smaller than 10 micrometres and are known as PM10 and PM2.5. These particles can be absorbed into the bloodstream and transported throughout the body.

The main reason air pollution damages our bodies is because of the inflammation that results from our immune system's response to the particles. The immune cells think the particles are bacteria and try to kill them by releasing enzymes and acids. These inflammatory proteins spread into the body, affecting the brain, the kidneys, the pancreas, and so forth.

Air pollution has been linked to a wide range of health issues, including:

• Heart disease
• Strokes
• Lung cancer
• Asthma
• Chronic laryngitis
• Osteoporosis
• Skin ageing
• Eye problems
• Dementia
• Miscarriages
• Low birthweight
• Neurodevelopmental and metabolic diseases in children

Air pollution can lead to heart attacks by narrowing arteries and weakening muscles

Air pollution is a complex mixture of thousands of components, including particulate matter, volatile organic compounds, and gases such as ozone, nitrogen dioxide, and sulfur dioxide. These pollutants can have harmful effects on human health, including increased cardiopulmonary morbidity and mortality, reproductive disorders, and cancers.

Particulate matter, which includes coarse, fine, and ultrafine particles, is of particular concern due to its ability to penetrate deeply into the respiratory tract and be deposited in the tracheobronchial and alveolar regions. Exposure to particulate matter has been linked to increased morbidity and mortality from respiratory and cardiovascular diseases, asthma exacerbation, and lung cancer.

One of the main mechanisms by which air pollution affects human health is through the induction of oxidative stress, which can lead to systemic inflammation, endothelial dysfunction, atherothrombosis, and arrhythmogenesis. Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the activation of antioxidant defenses. ROS can damage cells and tissues, including the respiratory epithelium, leading to inflammation and cell death.

Air pollution has also been shown to affect the cardiovascular system directly by entering the circulatory system and penetrating the pulmonary epithelium. It can also act indirectly by causing pulmonary oxidative stress, leading to a systemic inflammatory state. This systemic inflammation can increase the risk of cardiovascular events such as heart attacks and stroke.

In addition to the respiratory and cardiovascular systems, air pollution has been linked to a wide range of health issues, including liver and kidney problems, bladder cancer, diabetes, and neurological disorders such as Parkinson's and autism. It can also affect reproduction, with studies showing reduced fertility, increased miscarriages, and low birth weights associated with exposure to air pollution.

The impact of air pollution on human health is a growing area of research, and more studies are needed to fully understand the mechanisms by which different pollutants affect the body. However, the evidence suggests that air pollution can have far-reaching consequences, potentially affecting every organ and cell in the human body.

Air pollution can cause respiratory problems, including asthma, chronic laryngitis and lung cancer

Air pollution can have a detrimental impact on human health, and has been linked to a range of respiratory issues, including asthma, chronic laryngitis, and lung cancer.

Asthma

Air pollution can trigger asthma flare-ups, particularly in children. Pollutants in the air irritate the airways, causing them to swell and tighten, which leads to breathing problems. They can also make children more susceptible to upper respiratory infections, which can, in turn, trigger asthma symptoms. Furthermore, pollutants can increase the sensitivity of the lungs to allergens.

Chronic Laryngitis

Chronic laryngitis is a condition characterised by chronic inflammation of the larynx, which can be caused by long-term exposure to toxic chemicals and air pollution. A study in South Korea found a positive correlation between elevated levels of exposure to particulate matter and the risk of chronic laryngitis.

Lung Cancer

Air pollution has been linked to an increased risk of lung cancer. Research suggests that outdoor air pollution causes around 1 in 10 cases of lung cancer in the UK. While smoking is a much bigger risk factor, air pollution can still play a role in the development of cancer. The tiny particles in the air may build up in the lungs, causing damage to DNA in cells and changing how they divide, which can lead to cancer.

Air pollution can cause osteoporosis and increase the risk of bone fractures

Air pollution has been linked to a wide range of negative health impacts, including osteoporosis and an increased risk of bone fractures. A study by Columbia University's Mailman School of Public Health found that exposure to air pollution is associated with osteoporosis-related loss of bone mineral density and an increased risk of bone fractures, particularly in older adults. This is because air pollution causes systemic oxidative damage and inflammation, which can accelerate bone loss.

Furthermore, air pollution has been shown to cause respiratory diseases, cardiovascular and reproductive disorders, cancers, impaired cognition, and chronic obstructive pulmonary disease (COPD). It can also lead to systemic inflammation, which can have detrimental effects on overall health.

Asian countries are particularly vulnerable to the effects of air pollution on osteoporosis and bone fractures due to the high risk of osteoporosis in Asian ethnicity. The Asian Federation of Osteoporosis Societies (AFOS) projected that the number of bone fractures caused by osteoporosis will increase significantly in Asia in the coming decades, resulting in a substantial increase in healthcare costs.

Overall, air pollution has far-reaching impacts on human health, and its effects on osteoporosis and bone fractures are a significant concern, especially in vulnerable populations.

Air pollution can cause skin ageing, hives and eczema

Air pollution can cause skin ageing, hives, and eczema.

Skin Ageing

Air pollution is a harmful environmental risk to human skin and is known to promote ageing and inflammation of the tissue, leading to the onset of skin disorders and the appearance of wrinkles and pigmentation issues. The skin is the largest and outermost organ of the human body and acts as a protective barrier between the internal and external environment. Skin ageing is a result of two cumulative and overlapping mechanisms: intrinsic and extrinsic ageing. The process of intrinsic or chronological ageing affects all tissues and organs of the body and is influenced by genetic background. The main signs of intrinsic ageing in the skin are relatively mild, including the accumulation of fine wrinkles with moderate changes in skin pigmentation. In addition, the skin is continuously exposed to environmental and lifestyle factors such as sunlight, pollution, cigarette smoke, and dietary habits. These factors, collectively denominated the skin exposome, are the major causes of the process of extrinsic skin ageing. Major characteristics of extrinsic skin ageing are coarse wrinkles, solar elastosis, and pigmentation irregularities.

Air pollution, particularly particulate matter, can cause skin tanning, skin ageing, and inflammatory skin diseases such as atopic dermatitis, acne, and allergic reactions. Particulate matter can penetrate the body either by systemic distribution through the blood circulation after entering the lungs' alveoli or by infiltrating the skin through hair follicles. Exposure of the skin to urban air pollution activates mechanisms of cell detoxification, which, if active over a longer period, can lead to DNA and protein damage, elevated levels of reactive oxygen species (ROS), and lipid peroxidation, resulting in skin alterations such as impaired barrier function, pigment spots, wrinkles, and decreased skin hydration.

Hives

Hives, also called urticaria, is a spontaneous skin reaction that occurs in response to specific allergens. Most people experience hives at least once in their lifetime, brought on by specific foods, medications, insect bites, sunlight, pet dander, or another environmental trigger. In some cases, it is easy to identify what your body is reacting to. For instance, you may pet a neighbour's cat and see hives appear on your hand immediately afterward. Other times, it can be difficult to discern a direct cause. You may find that outbreaks occur more frequently while you're indoors, for example, but there may not be any clear pattern as to when or why symptoms appear. If the latter scenario rings true for you, it is possible that air pollution (indoor or outdoor) is at fault for your discomfort. For some people, an increase in airborne pollutants like particulate matter, volatile organic compounds (VOCs), ozone (O3), and nitrogen dioxide (NO2) can trigger a hives outbreak.

Eczema

Eczema, also known as atopic dermatitis (AD), is a chronic skin condition that causes red, itchy patches on the skin that can periodically flare up in response to environmental triggers. Although the primary risk factor for developing eczema is genetic (i.e. if you have a family history of allergies and skin conditions), research shows that environmental factors like air pollution, humidity, and temperature play a significant role in triggering and aggravating symptoms. Aside from family history, exposure to specific indoor pollutants such as airborne chemicals (VOCs) and particulate matter may also increase your risk of developing eczema at a young age, through what is referred to as "gene-environment interactions."

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