Lungs And Air Pollution: Recovery And Resilience

Air pollution is a serious environmental and health issue, causing up to 11.8% of global fatalities annually. It is a complex issue influenced by climate change, with extreme weather events and temperature changes amplifying pollution levels. The respiratory tract is a primary target of air pollution, with vulnerable populations such as children, older adults, and those with pre-existing respiratory conditions being at higher risk of adverse health effects. While the lungs are self-cleaning organs, the impact of air pollution on lung health is a growing concern.

Breathing polluted air can irritate the lungs and cause shortness of breath, coughing, wheezing, asthma flare-ups, and chest pain. Prolonged exposure to air pollution has been linked to the development of respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. The evidence suggests that air pollution can trigger exacerbations in those with pre-existing respiratory conditions and may also contribute to the development of new cases.

The impact of air pollution on lung health is an area of ongoing research, and while some studies have found associations between air pollution and respiratory diseases, the evidence is not conclusive. However, it is clear that air pollution has detrimental effects on lung health, and addressing this issue is crucial for protecting public health. Implementing strategies to reduce air pollution and raising awareness about its impact on lung health are essential steps towards safeguarding both the environment and public well-being.

Lung cancer

Research has shown that air pollution can cause lung cancer, with overwhelming evidence linking particle pollution to this deadly disease. The World Health Organization (WHO) and other health organizations have concluded that particulate matter contributes to the development of lung cancer. The small size of these particles allows them to bypass the body's natural defenses and become trapped deep in the lungs, potentially entering the bloodstream and causing damage.

The impact of air pollution on lung cancer risk varies globally, with some regions experiencing higher levels of pollution and, consequently, a greater burden of lung cancer cases. Low and middle-income countries with large populations often have significantly higher exposure levels. Additionally, certain vulnerable populations, such as children, older adults, and individuals with pre-existing respiratory conditions, are at a higher risk of developing lung cancer due to air pollution.

While the effects of air pollution on lung cancer are concerning, it is important to note that individuals can take steps to protect themselves. Reducing exposure to air pollution, advocating for stricter emission controls, and implementing public health measures can help mitigate the impact of air pollution on lung cancer risk. Additionally, not smoking, maintaining a healthy weight, practicing sun safety, and moderating alcohol consumption are proven ways to reduce lung cancer risk.

Lungs are self-cleaning organs, and their healing process begins once exposure to pollutants stops. Some techniques to improve lung health include steam therapy, controlled coughing, and postural drainage. Regular exercise is also beneficial, as it increases the body's breathing rate and improves circulation, aiding in the removal of excess carbon dioxide.

Asthma

Air pollution can cause asthma and other lung diseases. It can also worsen asthma symptoms, leading to increased hospital visits and even early death.

Air pollution can increase the risk of getting asthma or worsen the symptoms if you already have it. Small airborne particles, found in haze, smoke, soot, and airborne dust, can lead to serious air quality problems. These particles can irritate the airways and make asthma worse.

Ozone, a common air pollutant, is particularly harmful when found closer to the ground in the air we breathe. It is associated with worsening respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD).

Who is most at risk?

People with lung disease like asthma are at greater risk from breathing in small particles and irritating gases. Other groups most at risk from harmful effects of air pollution include:

• People with heart disease
• People who work outside
• People who are active or exercise outdoors
• Individuals who are pregnant and their foetuses
• People who live near sources of pollution (busy roadways, power plants, industrial facilities, oil and gas production sites)
• People who have lower incomes
• Black communities, Hispanic communities, and Native American/Indigenous communities

• Limit time outdoors, especially from 11 a.m. to 8 p.m.
• Stay in a well-ventilated, preferably air-conditioned, building
• Do not exercise or work outdoors when the Air Quality Index (AQI) is at unhealthy levels
• Make small changes to your home such as removing or reducing allergens, preventing mould growth, avoiding scented products, etc.

Chronic obstructive pulmonary disease (COPD)

Air pollution can have detrimental effects on respiratory health, and it is a significant environmental factor responsible for millions of premature deaths per year. It can escalate respiratory diseases, especially in vulnerable populations such as children, older adults, and those with pre-existing respiratory disorders like chronic obstructive pulmonary disease (COPD).

COPD is a long-term lung disease that includes chronic bronchitis and emphysema, and it is characterised by chronic airway inflammation, mucus hypersecretion, and progressive airflow limitation. The main cause of COPD is smoking, but non-smokers can also develop the disease over time due to exposure to irritants that damage the lungs and airways. Symptoms of COPD include frequent coughing or wheezing, excess phlegm, and shortness of breath.

While there is no cure for COPD, it is often preventable and treatable. Early detection is crucial, and healthcare providers can help patients develop a COPD action plan, including lifestyle changes to manage the disease and improve their quality of life. These lifestyle changes may include regular exercise, which can be beneficial even for those with chronic lung conditions. Additionally, certain foods, such as green tea, and dietary changes can help reduce lung inflammation.

It is important to note that constant exposure to elevated particle pollution will contribute to reduced respiratory function, even in healthy individuals. Therefore, taking steps to reduce exposure to air pollution is essential to mitigate the severity of lung and systemic adverse health effects.

Respiratory infections

Respiratory tract infections (RTIs) are infections of the body's breathing apparatus, including the sinuses, throat, airways, and lungs. These infections can be caused by viruses or bacteria and are typically contagious. RTIs are usually self-limiting and resolve within 1 to 2 weeks without treatment. However, in some cases, medical attention may be required, especially if symptoms persist or worsen.

Upper respiratory infections affect the sinuses and throat, while lower respiratory infections involve the airways and lungs. Lower respiratory infections tend to be more severe and last longer.

Common symptoms of RTIs include a cough, which may produce mucus (phlegm), a stuffy or runny nose, breathlessness, a tight chest, wheezing, and a general feeling of being unwell.

To manage symptoms at home, it is recommended to drink plenty of fluids, especially water, to loosen mucus and make it easier to cough up. A hot drink made with lemon and honey can help soothe a cough, but this remedy is not suitable for babies under one year old. Gargling with warm salty water can alleviate a sore throat, but this practice is not recommended for children. Propping your head up with extra pillows while sleeping can aid breathing and help clear mucus from the chest. Over-the-counter painkillers can reduce fever and ease sore throat, headache, and muscle pain.

It is important to avoid smoking, as it can aggravate symptoms. Additionally, it is crucial to cover your mouth when coughing or sneezing and to wash your hands regularly to prevent the spread of RTIs to others.

In some cases, respiratory infections can lead to serious complications, such as respiratory failure due to elevated carbon dioxide levels in the blood, or the spread of infection to other parts of the body, such as the brain or heart. Therefore, it is essential to seek medical advice if you experience severe symptoms, such as high fever, rapid or difficult breathing, frequent and severe coughing, wheezing, or stridor (a harsh, raspy sound when breathing in).

While most RTIs are caused by viruses and do not respond to antibiotics, bacterial infections, such as strep throat or pneumonia, may require antibiotic treatment. It is important to complete the full course of antibiotics as advised by your healthcare provider, even if your symptoms improve.

Lung inflammation

Air pollution is a major public health concern, affecting nine out of ten individuals living in urban areas worldwide. Exposure to air pollution is the ninth leading risk factor for cardiopulmonary mortality. The lungs are self-cleaning organs, but constant exposure to elevated particle pollution will contribute to reduced respiratory function.

Types of Air Pollutants

Air pollutants can be solid particles, liquid molecules, or gases. They can be primary (directly produced) or secondary (formed by the interaction of primary pollutants). Some pollutants can be both produced directly and formed by the reaction of other pollutants. Examples of air pollutants include:

• Particulate Matter (PM)
• Ozone (O3) or Tropospheric O3 or ground-level O3
• Carbon Monoxide (CO)
• Nitrogen Dioxides (NO2)
• Sulphur Dioxide (SO2)
• Volatile Organic Compounds (VOCs)

Health Consequences of Exposure to Air Pollution

The analyses of recent epidemiological studies have provided coherent evidence that elevated levels of air pollution are associated with an increased risk of respiratory diseases, chronic obstructive lung diseases (COPD), cancers, cerebrovascular strokes, cardiovascular diseases, and mortality. These occur due to the nature of the pollutants and their impacts on the respiratory and cardiovascular systems.

Air pollution has also been shown to affect foetal development and preterm birth, with decreases in neonate birth weight associated with exposure to air pollution. Children are very susceptible to the harmful effects of pollution exposure, with an increase in the number of young children admitted to hospitals for acute lower respiratory infection. These respiratory infections are the largest causes of mortality among young children worldwide, especially in developing countries.

Oxidative Stress and Air Pollution

The mechanism responsible for the adverse effect of oxidant pollutants in the lungs is their direct and indirect oxidative reaction with molecules and cells present in the airways. This might result in oxidative stress in the airway tissues. Oxidative stress can be defined as damage that might occur in cell components, such as membranes, RNAs, and DNA, as a result of an imbalance in the body's ability to neutralize certain molecules or to repair the resulting damage.

Airway inflammation can be characterized by an increase in inflammatory cells, such as neutrophils and macrophages, as well as inflammatory mediators: interleukin-6 (IL-6), interleukin-8 (IL-8), and prostaglandins. An increase in neutrophil numbers and percentage is a good indicator of the beginning of an inflammatory response.

Inhalation of air pollution has been shown to stimulate airway inflammation due to its oxidative nature. Airway inflammation can lead to the destruction of the cilia of the epithelial cells that line the respiratory tract. The cilia have an important immune function as they constantly move the mucus up from the lungs to the back of the throat where it is eliminated or swallowed and digested. The mucus serves as a "trap" to infectious agents and small particles, such as pollutants and allergens, preventing them from entering deep into the airways.

Air Pollution, Exercise, and Antioxidant Supplementation

The respiratory tract lining fluid is the first barrier encountered by inspired gases and, therefore, has a network of antioxidants, such as ascorbic acid, GSH, α-tocopherol, and uric acid, to provide protection against oxidative stress. For this reason, antioxidant supplementation has been suggested as a benefit for people exercising in an air-polluted environment. The rationale behind such a hypothesis is that increasing the availability of antioxidants in the respiratory tract lining fluid will provide additional sacrificial substrates for the oxidant, thereby decreasing oxidation reactions occurring within this fluid and within the underlying epithelial cells.

Some studies have investigated the proposed benefit of increasing antioxidant availability in individuals exposed to ozone pollution by supplementing the participants with a mix of antioxidants, mostly vitamins C and E.

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