How polluted air undermines human health

Polluted air is not only black clouds emanating from industrial pipes, smog enveloping cities, or exhaust gases with a suffocating odor. Pollution can be completely invisible and imperceptible, but at the same time create a huge danger to human health.

Studies show that 9 out of 10 people in the world breathe polluted air. It is because of him that every year about 7 million people die prematurely from heart attacks, stroke, diabetes, diseases of the respiratory system. Bad ecology takes more lives than AIDS, tuberculosis and malaria put together ^{[1] [2]}.

Air pollution: what is it?

The air we breathe is a mixture of gases, the main constituents of which are nitrogen, oxygen and carbon dioxide. In addition to them, neon, helium, krypton, argon, methane and hydrogen are also present in some quantity. Despite the fact that 100 liters of air contains about 21 liters of oxygen, about 78 liters is nitrogen, the rest is other gases, O2 is the main one for all life on the planet ^[3].

It would be a mistake to assume that the composition of air is a constant characteristic. In different regions of the world, it can differ significantly. And when it contains substances that should not have been, or the concentration of certain gases is too high, they talk about pollution.

Atmospheric pollutants are usually divided into 2 categories:

• natural (appear after forest fires, volcanic eruptions, hurricanes, etc.);
• artificial (the result of human activity).

Among the most common pollutants, researchers name ^[4]:

• ground level ozone;
• carbon monoxide;
• sulfur dioxide;
• nitrogen dioxide;
• solid particles.

Importantly, when in 1970 scientists analyzed the quality of the environment, polluted air was primarily considered as a threat to the organs of the respiratory system. But in the last decade, other diseases have been included in this list. ^[5], including:

• cardiovascular;
• diabetes;
• obesity;
• disorders of the immune, reproductive and nervous systems.

And in 2013, WHO ranked air pollution as a carcinogen, that is, it is one of the factors that cause cancer. ^[6]. In particular, scientific studies show that the toxic substances contained in it increase the risk of breast cancer in women, malignant degeneration of lung cells, and the appearance of leukemia. But there are other equally dangerous “side effects” of regularly inhaling polluted air. ^[5]. So, its effect on pregnant women increases the risk of having a child with insufficient body weight, autism, neural tube defects, lower IQ. Older people living in polluted areas are at increased risk of early dementia and Alzheimer’s disease.

Short-term effect on the body

Even if polluted air is inhaled for a short time, the human body will feel its negative impact. And the first in this case, the respiratory system suffers. Pollutants deposited in the respiratory tract can cause respiratory problems, decrease lung function, and exacerbate asthma in those with this disease. In addition, if the air contains a high concentration of sulfur dioxide, even with short-term exposure, it can cause irritation to the skin, respiratory tract and mucous membranes of the eyes. ^[7].

Consequences of long-term exposure

Much more serious consequences arise if you breathe polluted air constantly. Based on long-term research results ^{[7] [8]}, scientists came to the conclusion that it can cause a variety of diseases:

• chronic obstructive pulmonary disease (according to WHO, the cause of 43% of COPD cases is polluted air);
• lung cancer (the cause of 29% of all cases, this indicator is especially affected by particulate matter, which, together with inhaled gases, reaches the lower respiratory tract, causing damage);
• cardiovascular disease (studies have shown that people living in regions with high levels of pollution are more at risk of dying from a stroke or heart attack).

In addition, according to a study published in 2019 ^[9]Air pollution increases the risk of preterm birth in women.

How different types of pollutants affect humans

Experts have studied how the human body is affected by different types of pollutants contained in the air. And one of the most dangerous were solid particles.

When talking about particulate matter contained in the air, they primarily mean soot and dust. Most of them are a product of coal combustion in industrial facilities, and they are also found in exhaust gases. Large particulate matter (up to 10 microns in size) can damage the nasal cavity and upper respiratory tract. Small ones (up to 2,5 microns in diameter) penetrate the lungs and provoke heart attacks, strokes, bronchitis, asthma, as well as premature death due to cancer, cardiovascular and pulmonary diseases. In addition, studies show that air with a high content of fine particulate matter can adversely affect brain development in babies.

Dangerous for asthmatics and smog, which mainly consists of the so-called harmful, ground-level ozone.

If the concentration of carbon monoxide in the air is excessive, it can cause symptoms identical to carbon monoxide poisoning. In such cases, there is weakness, dizziness, vomiting, headache, confusion.

Sulfur dioxide, a by-product of burning oil and coal, is also one of the main pollutants. Inhalation of this substance increases the risk of diseases of the respiratory and cardiovascular systems. Moreover, such air causes irritation of the mucous membrane of the eyes.

Nitrogen oxides enter the air as part of exhaust gases. Human exposure to this substance can cause coughing, wheezing, throat irritation, headaches, and fever. This pollutant is dangerous for people with asthma and also increases the risk of heart disease. ^{[1] [7]}.

It is quite difficult for a resident of megacities to protect themselves from inhaling polluted air. But in order to at least slightly improve the condition of the body, cleanse it of toxins, it is worth getting out of the city as often as possible and spending time in nature.

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