Air Pollution's Dark Side: Diseases And Disorders

Air pollution is a major cause of disease and premature death worldwide. It is linked to a wide range of diseases, including respiratory illnesses, cancers, gastrointestinal disorders, and neurological conditions. The health impacts of air pollution depend on the types, sources, and concentrations of pollutants in the air, with fine particulate matter (PM2.5) being a critical pollutant driving significant health problems. Both short-term and long-term exposure to air pollution can lead to serious health issues, and vulnerable populations such as children, the elderly, and pregnant women are at an increased risk of developing air pollution-related diseases.

Cancer

Air pollution is a major cause of disease and premature death. Fine particulate matter (PM2.5) is the air pollutant driving the most significant health problems. These fine particles can penetrate deep into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells.

Outdoor air pollution causes roughly 1 in 10 cases of lung cancer in the UK. Globally, air pollution is estimated to cause nearly seven million deaths per year, including lung cancer deaths. According to the Lancet Commission on pollution and health, air pollution alone causes up to 29% of all lung cancer deaths.

There are a few ways in which air pollution can cause lung cancer. One theory is that tiny particles build up in the lungs and damage the DNA in cells, changing how they divide and leading to cancer. Another theory is that these particles cause inflammation in the lungs, which can also lead to cancer. Research has also found that air pollution is associated with an increased risk of mortality for several other types of cancer, including breast, liver, and pancreatic cancer.

In addition to lung cancer, indoor air pollution can increase the risk of other cancers. A key source of indoor air pollution in the UK is second-hand smoke from cigarettes, cigars, and pipes. Burning wood and coal to heat homes or cook with can also add to indoor air pollution. Most exposure to second-hand tobacco smoke happens in the home, increasing the risk of lung cancer and other health conditions like heart and lung diseases.

Air pollution is a significant and far-reaching threat to public health, with 99% of the world's population breathing unhealthy air, according to the World Health Organization (WHO). Reducing air pollution can help prevent lung cancer and promote overall health.

Respiratory diseases

Air pollution is a major risk factor for respiratory diseases. It can cause and exacerbate a variety of respiratory issues, from asthma to lung cancer.

Asthma

Air pollution is a known trigger of asthma symptoms, including bronchoconstriction, coughing, wheezing, and chest pain. Children are particularly vulnerable, with higher deposition of particle pollution in the tracheobronchial region of their lungs. Poor inner-city children are at increased risk due to proximity to high-density traffic and industrial pollution sources, as well as poor indoor air quality. Particle pollution can aggravate pre-existing airway inflammation, increasing pro-inflammatory mechanisms and accelerating the inflammatory cascade.

Chronic Obstructive Pulmonary Disease (COPD)

COPD is a major cause of disability and mortality, particularly in developing countries. Air pollution, especially from burning fossil fuels, can cause inflammation in the airways and lungs, impair pulmonary function, and lead to acute exacerbations of COPD. Women in developing countries are at high risk due to exposure to household wood smoke from cooking.

Lung Infections

Air pollution increases the risk of lung infections such as bronchitis and pneumonia. It can also cause shortness of breath, coughing, and tightness in the chest, making it harder to breathe.

Lung Cancer

Breathing in particulate matter (PM), especially the smaller 'fine' particles like PM2.5, and ultrafine particles, can play a role in the development of lung cancer. These fine particles can reach the breathing sacs in the lungs and even cross into the bloodstream, carrying toxic chemicals linked to cancer.

Other Respiratory Issues

Air pollution can irritate the airways, increase respiratory symptoms, and affect lung function. It is also associated with higher hospitalization rates for people with lung conditions and a higher prevalence of childhood asthma.

Reducing exposure to indoor and outdoor air pollution, improving air quality through filtration systems, and taking measures to reduce pollutant inhalation can help mitigate the respiratory health risks associated with air pollution.

Neurological disorders

Air pollution is a major global public health problem, causing 6.5 million deaths worldwide in 2015. According to the World Health Organization, 4.2 million and 3.8 million people die prematurely each year due to external and indoor air pollution, respectively. While most research on the hazards of air pollution focuses on lung and cardiovascular diseases, air pollution is also associated with a range of neurological disorders.

The impact of air pollution on neurological health is not widely recognized, and the mechanisms underlying neurological diseases induced by air pollutants are not yet fully understood. However, several studies have found links between air pollution and various neurological disorders. These include:

• Alzheimer's disease and Parkinson's disease: A growing body of evidence suggests a link between air pollution and these neurodegenerative disorders. For example, a study of hospital admissions data from 63 million older adults in the US found that exposure to PM2.5 was associated with increased rates of dementia.
• Anxiety disorders: Air pollution-induced inflammation and oxidative stress in the brain may amplify anxiety symptoms. Pollutants can also disrupt neurotransmitter balance in the brain, affecting serotonin and dopamine levels, which are crucial in regulating mood and anxiety.
• Cognitive decline: Exposure to air pollutants has been linked to poor brain health and an increased risk of cognitive decline.
• Multiple sclerosis: Air pollution may trigger and aggravate multiple sclerosis through an inflammatory reaction.
• Epilepsy: A common neurological disorder characterized by abnormal neuronal excitability and unpredictable recurrent seizures.
• Other neurological disorders: Air pollution has also been linked to an increased risk of other neurological and psychiatric disorders, including dementia, depression, schizophrenia, attention deficit hyperactivity disorder (ADHD), and Autism Spectrum Disorder (ASD).

In addition to these specific neurological disorders, air pollution has been associated with structural brain changes and increased inflammation, contributing to various neurological issues. Prolonged exposure to polluted air can lead to alterations in neurotransmitters and increased inflammation, which can have detrimental effects on brain health.

Gastrointestinal disorders

Air pollution is a major environmental and health risk, causing millions of deaths annually. It is the leading environmental health risk in Europe and a significant cause of premature death and disease. Fine particulate matter (PM2.5) is the air pollutant that causes the most harm, leading to premature mortality and serious health issues. Other dangerous air pollutants include carbon monoxide, nitrogen dioxide, ozone, and sulphur dioxide.

Several gastrointestinal disorders have been linked to air pollution. These include irritable bowel syndrome, Crohn's disease, ulcerative colitis, and inflammatory bowel disease (IBD). People who live in areas with high levels of air pollution are more likely to suffer from these conditions. Symptoms of gastrointestinal disorders can include abdominal pain, diarrhoea, constipation, and bloating.

Research has shown that exposure to particulate matter can trigger the onset of gastrointestinal disease. Studies have found that ingestion of particulate matter increases intestinal permeability and is accompanied by an inflammatory response. This disruption of the intestinal barrier has been associated with a range of diseases, including IBD and celiac disease.

Air pollution is thought to play a role in the development of IBD by changing the gut microbiome, which causes an abnormal immune response and inflammation. This can be triggered by environmental factors, such as diet and stress, as well as genetic factors.

Kidney diseases

Air pollution is a complex mixture of gaseous components and suspended particles, including harmful gases and solid and liquid particles. It is a well-known environmental hazard and a public health problem, contributing to the premature deaths of approximately 428,000 people in Europe annually.

Air pollution has been linked to various diseases, including respiratory and cardiovascular issues. However, its impact on kidney function is only recently beginning to be acknowledged. Studies have found a connection between air pollution and the development of chronic kidney disease (CKD). For example, a study in the United States found that for every increase of 10 micrograms of pollutants per cubic meter of air, there was a 25-37% increase in new cases of kidney disease, a 36% increase in rapid kidney function loss, and a 31% higher risk of kidney failure.

The exact mechanisms by which air pollution damages the kidneys are still not fully understood. One theory suggests that small pollution particles can enter the bloodstream after being inhaled into the lungs. These particles are then filtered by the kidneys, causing damage over time. Additionally, pollutants can induce inflammatory mediators in the lungs, which can spill over into the circulation, resulting in systemic inflammation and oxidative stress, further damaging the kidneys.

While the specific air pollutants responsible for kidney damage are yet to be characterized, PM2.5 exposure has been implicated in several studies. Other pollutants, such as toxic metals, cigarette smoke, and gases, are also believed to play a role in harming kidney function.

In summary, air pollution is a significant contributor to kidney diseases, particularly CKD. The exact mechanisms and specific pollutants involved are still being studied, but the evidence suggests a strong link between air pollution and adverse effects on kidney health. More research is needed to establish cause-and-effect relationships and develop effective strategies to mitigate the impact of air pollution on kidney function.

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