Air Pollution Hazards: Understanding Deadly Diseases

Air pollution is a significant environmental health hazard that affects people worldwide. It is caused by various human activities, such as vehicle emissions, industrial processes, and the combustion of solid fuels, and has been linked to a range of diseases and health conditions. The health impacts of air pollution depend on the types and concentrations of pollutants, with fine particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulphur dioxide being major pollutants of concern. These pollutants can lead to both short-term and long-term health problems, including respiratory infections, cardiovascular diseases, cancer, metabolic dysfunctions, neurological disorders, and skin diseases. Vulnerable groups, such as children, older adults, and pregnant individuals, are at an increased risk of adverse health effects from air pollution exposure.

Respiratory diseases such as asthma, bronchitis, and chronic obstructive pulmonary disease

Air pollution is a major cause of disease and premature death, with fine particulate matter (PM2.5) being the most significant pollutant driving health problems. Respiratory diseases are a key concern, with asthma, bronchitis, and chronic obstructive pulmonary disease (COPD) all impacted by air pollution.

Asthma is a condition that causes the airways to become inflamed and narrowed, leading to symptoms such as wheezing, coughing, and difficulty breathing. Air pollution can trigger asthma attacks and worsen symptoms, particularly in children. People with asthma are more susceptible to the effects of air pollution, and hospital admissions and emergency department visits for asthma have been linked to increased pollution levels.

Bronchitis, including chronic bronchitis, is also affected by air pollution. Short-term exposure to fine particles in the air can trigger acute bronchitis and irritate the airways, causing coughing and inflammation.

COPD is a chronic inflammatory condition affecting the airways and lungs. Air pollution can induce acute exacerbations of COPD, increasing respiratory morbidity and mortality. People with COPD are particularly vulnerable to the detrimental effects of air pollutants, which can further impair lung function and cause inflammation. Exposure to air pollution can make it harder for people with COPD to breathe and may increase their risk of respiratory infections.

The effects of air pollution on respiratory diseases are influenced by various factors, including age, genetics, comorbidities, and sociodemographic factors. Children, adolescents, the elderly, and pregnant women are more susceptible to the health impacts of air pollution. Additionally, low-income communities and minority populations are disproportionately exposed to air pollution and are at higher risk of adverse health outcomes.

Gastrointestinal disorders including irritable bowel syndrome, Crohn's disease, and ulcerative colitis

Air pollution has been linked to a wide range of diseases, with pollutants such as particulate matter (PM), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), and sulphur dioxide (SO2) being of the highest public health concern. While most research on the health effects of air pollution has focused on respiratory and cardiovascular systems, there is growing evidence that air pollution can also have adverse effects on the gastrointestinal tract.

Irritable Bowel Syndrome (IBS)

IBS is a functional gastrointestinal disorder characterised by abdominal pain or discomfort and altered bowel habits. The exact causes of IBS are not yet fully understood, but recent studies indicate that environmental pollution may play a role in the development of the condition. Specifically, air pollution, bacterial contamination, radiation, and stress have been identified as potential triggers of IBS. The dramatic rise in urban population growth means that the quality of the environment, particularly urban air pollution, will play an increasingly significant role in public health.

Crohn's Disease

Air pollution is considered an environmental factor contributing to intestinal disease, including Crohn's disease. Exposure to air pollutants, particularly particulate matter (PM), has been linked to intestinal inflammation and disease. While there has been limited research on the specific effects of air pollution on intestinal diseases, it is suggested that air pollution may impact the development of Crohn's disease through direct effects on epithelial cells, systemic inflammation, immune activation, and modulation of the intestinal microbiota.

Ulcerative Colitis (UC)

Ulcerative colitis is a chronic inflammatory bowel disease (IBD) that causes inflammation in the colon and rectum. Environmental factors, including air pollution, may trigger flares, during which symptoms return or worsen. A 2019 study found that children who grew up with constant or regular exposure to air pollutants had an increased rate of developing UC.

Other Gastrointestinal Disorders

Air pollution has also been associated with other gastrointestinal disorders, including appendicitis and inflammatory bowel disease (IBD). The ingestion of particulate matter from air pollution can increase intestinal permeability and trigger an inflammatory response in the gut. This can lead to alterations in the gut microbiome and immune function, potentially contributing to the development of gastrointestinal disorders.

Kidney diseases, e.g. chronic kidney disease and acute kidney injury

Air pollution has become a potential contributor to the global burden of non-communicable diseases, including kidney disease. The detrimental effects of air pollution on the kidneys have only recently begun to be acknowledged. While the exact mechanisms of how air pollution impacts the human body are still unclear, there is a great deal of evidence for the short- and medium-term adverse effects of air pollution on the body.

Various pollutants, such as toxic metals, particulate matter (PM), cigarette smoke, and gases, have been identified as harmful to the kidneys. Heavy metals, in particular, are among the best-known environmental pollutants that cause kidney disease. These include cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), and uranium.

The inflammatory mediators induced by PM and other pollutants in the lungs can enter the bloodstream, resulting in systemic inflammation, oxidative stress, and damage to distant organs, including the kidneys. There is also evidence of direct harm to the kidneys from air pollution. For example, a retrospective cohort study in Hong Kong found a link between long-term exposure to fine particulate matter and mortality from renal failure.

Chronic kidney disease (CKD) is a significant global public health problem, with high rates of morbidity and mortality due to end-stage renal disease and associated cardiovascular disease. CKD is defined as either a reduced glomerular filtration rate (GFR < 60 mL/min/1.73 m2) or evidence of kidney damage, such as abnormal pathology or albuminuria, persisting for at least three months. The reported prevalence of CKD varies across regions, with a reported rate of 11.9% in Taiwan, where it is one of the leading causes of death.

To address the health risks associated with air pollution and kidney disease, regulatory strategies for pollution control and the reduction or prevention of exposure to environmental pollutants are essential. Implementing environmental protection strategies, establishing safe exposure levels, and raising awareness among policymakers and industry representatives to promote air quality standards and emissions controls are crucial steps in mitigating the impact of air pollution on kidney health.

Skin diseases like eczema, psoriasis, and acne

Air pollution is increasingly being recognized as a causative factor in common skin diseases. Skin is the body's first line of defense against the outside world, and air pollution can affect its structure and function.

Eczema, also known as atopic dermatitis, is a common skin condition that causes itchiness, rashes, dry patches, and infection. It is a type of dermatitis, which is a group of conditions that can inflame or irritate the skin. Air pollution may be a contributing factor to eczema. Doctors often diagnose eczema by examining the skin and asking the patient about their symptoms and any potential triggers. Allergy tests are also sometimes ordered, as eczema is often associated with allergies. To treat eczema, doctors may recommend wet wrap therapy, coal tar, calamine lotion, and relaxation techniques to reduce stress and scratching. Moisturizing creams can also be beneficial, but it is important to choose products that are fragrance- and dye-free and do not contain irritants such as citrus extract or lidocaine.

Psoriasis is another skin condition influenced by air pollution. Cadmium, an air pollutant found in battery and television manufacturing and the aircraft industry, has been identified as a contributor to the pathogenesis of psoriasis. Patients with severe psoriasis have been found to have higher blood cadmium levels compared to the general population, suggesting that environmental exposure to this pollutant may compromise immunity and contribute to the worsening of psoriasis symptoms.

Air pollution has also been linked to acne. A large epidemiological study in Beijing found that increased concentrations of traffic- and industry-related air pollutants were associated with a higher number of outpatient visits for acne vulgaris. Another independent clinical study investigated the relationship between exposure to common air pollutants and the number of acne lesions. Polycyclic aromatic hydrocarbons, commonly found in air pollution, are known to induce an inflammatory response in the skin, which could potentially increase acne. Additionally, UV exposure has an additive effect with airborne pollutants, compromising the skin barrier and leading to further skin sensitivity.

Overall, air pollution is a significant risk factor for various skin diseases, including eczema, psoriasis, and acne. It is important for healthcare providers to discuss the negative effects of air pollution with patients and explore strategies to mitigate its impact on skin health.

Cancer, particularly lung cancer

Air pollution is a major contributor to the global burden of disease. It is the single largest environmental health risk in Europe, and it is estimated that it causes millions of premature deaths annually worldwide.

One of the most well-established links between air pollution and disease is the association with cancer, particularly lung cancer. Outdoor air pollution is a known cause of lung cancer, with one study estimating that it causes roughly 1 in 10 cases of lung cancer in the UK. However, it is important to note that smoking has a much larger impact on lung cancer risk, causing around nine times more cases than air pollution.

The biological mechanisms by which air pollution can lead to lung cancer are still being investigated. One theory suggests that the tiny particles in air pollution may build up in the lungs and damage the DNA in lung cells, changing how these cells divide and leading to cancer. Another theory posits that these particles may cause inflammation in the lungs, which can also increase the risk of cancer.

In addition to lung cancer, there is some evidence to suggest that air pollution may be associated with other types of cancer. For example, a study found that living near major roadways may increase a woman's risk of developing breast cancer. Additionally, occupational exposure to benzene, an industrial chemical, has been linked to leukemia and non-Hodgkin's lymphoma. However, the evidence for these associations is more limited, and more research is needed to fully understand the role of air pollution in these cancers.

Indoor air pollution, caused by sources such as second-hand smoke, burning wood, and coal, is also a concern. This type of pollution can increase the risk of lung cancer, as well as other health conditions like heart and lung diseases. Household air pollution is responsible for millions of premature deaths each year, with a significant impact on women and children in low- and middle-income countries.

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