Air Pollution: A Lethal Risk To Our Health

Air pollution is a significant environmental health hazard that can have detrimental effects on human health. It is caused by the presence of contaminants such as dust, fumes, gases, and smoke in the atmosphere, which can be inhaled and lead to a range of adverse health outcomes. Both short- and long-term exposure to air pollution has been linked to an increased risk of respiratory and cardiovascular issues, including lung cancer, heart disease, and stroke. Certain populations, such as children, the elderly, and pregnant women, are more susceptible to the health impacts of air pollution, which can also vary depending on individual factors such as genetics, comorbidities, and nutrition. While air pollution is a global issue, it particularly affects urban areas, with almost four in ten people in the US and 97% of the urban population in Europe breathing air that exceeds recommended health guidelines.

Health Risks Caused by Pollution

Lung cancer and respiratory issues

Air pollution is the presence of one or more contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke or vapour, in quantities that can be harmful to human health. Particle pollution, also known as particulate matter, is a mix of tiny solid and liquid particles in the air. It can be made up of a number of components, such as acids, organic chemicals, metals, soil and dust particles.

In 2013, the World Health Organization (WHO) reviewed all the available science and concluded that particle pollution causes lung cancer. Research has also linked exposure to particulate matter to an increased risk of lung cancer among non-smokers. One study found that exposure to particulate matter promotes the growth of cells in the lungs that carry cancer-causing mutations. Another study found that around 300,000 lung cancer deaths in 2019 were attributed to exposure to particulate matter.

Particle pollution can also cause respiratory issues. Constant exposure to elevated particle pollution can contribute to reduced respiratory function. It can cause inflammation of the airways and lungs, bronchial hyperreactivity, respiratory infections, and decreased lung function growth in children. In addition, particle pollution can worsen pre-existing respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD).

Certain groups of people are more vulnerable to the health impacts of air pollution. These include children, the elderly, pregnant women, and people with pre-existing respiratory or cardiovascular diseases.

Heart disease

Air pollution is the presence of one or more contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke or vapour, in quantities and durations that can be harmful to human health. Fine particulate matter (PM2.5) is the air pollutant driving the most significant health problems and premature mortality. Particle pollution can increase the risk of lung cancer and heart attacks, and it can also cause early death.

The American Heart Association and other sources explain that air pollution can lead to heart disease. When you breathe in poor-quality air, the air pollutants can travel deep into your bloodstream through your lungs and to your heart. This can increase your risk of developing heart and circulatory diseases. Air pollutants can damage your blood vessels by making them narrower and harder, increasing your blood pressure because your heart is pumping faster to move the blood that cannot flow properly. This can increase the strain on your heart muscle by making it work harder than it should. It can also affect your heart's electrical system, which controls your heartbeat. These changes can be similar to those seen in the early stages of heart failure. For people with existing heart and circulatory conditions, this damage can increase their risk of events like a heart attack or stroke.

Research using publicly available data on more than one million adults in the U.S. found that long-term exposure to PM2.5 was associated with elevated risks of early death, primarily from cardiovascular causes, including heart disease, stroke, influenza and pneumonia. Another study of 68.5 million Medicare-enrolled adults in the United States between 2000 and 2016 found a 6-8% increase in the risk of all-cause mortality for every 10 µg/m3 increase in the annual average PM2.5.

Children and adolescents are particularly vulnerable to air pollution because their bodies, organs and immune systems are still developing. Air pollution damages health during childhood and increases the risk of diseases later in life. Maternal exposure to air pollution is associated with adverse birth outcomes, such as low birth weight, pre-term birth and small for gestational age births. A growing body of evidence also suggests that air pollution may affect diabetes and neurological development in children.

The health impacts of exposure to air pollution depend on the types, sources and concentrations of the pollutants. However, the health risks and disease pathways between ambient and household air pollution exposure are often similar due to their similar composition. Fine particulate matter, for example, is a common and critical pollutant in both ambient and household air pollution, leading to negative health impacts.

Diabetes

Several studies have found a link between air pollution and diabetes, with one global study suggesting that air pollution emitted by cars and trucks was responsible for 14% of diabetes cases in 2016. This figure includes 150,000 cases in the United States alone.

The particles in question are known as PM2.5, or particulate matter that is 2.5 micrometres big—30 times smaller than a human hair. They are emitted by various types of industry and fuel burning, but in the United States, the biggest source of PM2.5 is cars. When there is a lot of PM2.5 in the air, it may look smoggy or hazy, but in lighter concentrations, the particles are invisible.

PM2.5 is so harmful because of its size, which allows it to penetrate the lungs and enter the bloodstream, circulating to different organs and causing inflammation. This can lead to greater oxidative stress and adipose tissue inflammation, resulting in endoplasmic reticulum stress, insulin signalling abnormalities, and apoptosis. These processes may affect insulin resistance and metabolic disturbance, increasing the risk of developing diabetes.

The European Environment Agency (EEA) has found that exposure to NO2 led to 175,070 years lived with disability (YLDs) due to diabetes mellitus (Type 2 diabetes) in 31 European countries in 2019. Additionally, a study of Latino children in the United States found that those living in areas with more air pollution had a greater risk of developing type 2 diabetes.

Overall, the evidence suggests that air pollution is a significant risk factor for diabetes, and the implementation of policies and interventions to reduce air pollution and increase physical activity may help to mitigate this risk.

Neurological issues

Air pollution is a major public health concern, impacting the health of people worldwide. It is linked to a range of neurological issues that can affect the brain and nervous system, leading to various disorders and diseases.

One of the key ways in which air pollution impacts neurological health is by causing inflammation in the brain. This neuroinflammation can have several detrimental effects, including modifying neurotransmitter systems and emotional regulation circuits, which can amplify anxiety symptoms. Research has shown that air pollution-induced inflammation may be a factor in the development of anxiety disorders. Additionally, it can lead to structural changes in the brain, such as reduced fractional anisotropy and increased mean diffusivity, indicating a potential decline in neurological function.

Oxidative stress is another pathway through which air pollution affects neurological health. This can be caused by reactive oxygen species generated by air pollution, leading to neuronal damage and disrupted cellular function. This, in turn, can contribute to anxiety and other neurological disorders. Pollutants can also directly disrupt neurotransmitter balance in the brain, affecting serotonin and dopamine levels, which are crucial for regulating mood and anxiety.

Air pollution has been associated with an increased risk and exacerbation of several neurological diseases, including Alzheimer's, Parkinson's, dementia, anxiety, and depression. These links have been observed in various studies, highlighting the need for policy interventions to address air pollution as a modifiable risk factor for neurological diseases.

Furthermore, air pollution may also impact neurological development in children. Evidence suggests a potential link between air pollution and neurological disorders like Autism Spectrum Disorder (ASD). Additionally, children and adolescents are more vulnerable to the effects of air pollution as their bodies and immune systems are still developing, which can increase their risk of developing neurological issues later in life.

The impact of air pollution on neurological health is a growing concern, and further research is needed to fully understand the mechanisms by which air pollutants affect the central nervous system. However, the current evidence underscores the importance of mitigating air pollution to protect public health and reduce the prevalence of neurological disorders.

Adverse birth outcomes

Air pollution is a critical health concern for pregnant people and their developing babies. It can negatively affect pregnancy, possibly leading to various adverse birth outcomes. Maternal exposure to air pollution is associated with several adverse birth outcomes, including preterm birth, low birth weight, and small for gestational age births.

A study in the city of Durban, South Africa, found that increased levels of ambient air pollution were a major health concern. The Mother and Child in the Environment (MACE) birth cohort study in Durban from 2013 to 2017 examined the impact of prenatal exposure to PM2.5, SO2, and NOx on birth outcomes. Results indicated that exposure to PM2.5 had significant direct and indirect effects on adverse birth outcomes.

Additionally, a study in the U.S. state of Kansas from 2000 to 2015 found a positive link between increased ozone (O3) exposure during pregnancy and a higher risk of preterm birth, gestational hypertension (GH), and decreased birth weight. The study also observed that O3 exposures in the first trimester were connected to an elevated risk of GH.

The children of parents who live in polluted areas or are exposed to indoor air pollution from toxins, such as cigarette smoke, have higher rates of negative birth outcomes. These can include preterm birth, low birth weight, stillbirth, congenital abnormalities, and underdeveloped lungs.

Furthermore, exposure to air pollution during pregnancy has been linked to an increased risk of pregnancy-related complications such as preeclampsia and high blood pressure, which can harm both the parent and the baby and may even necessitate an early birth.

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