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How does air quality influence our lungs?

When the air we breathe is a threat, how do we take care of the "silent killer"?

 

 

Air pollution and climate change are some of the biggest environmental threats to our health, causing around 7 million preventable deaths a year.

The World Health Organization (WHO) has recently published new global guidelines on air quality, which provide clear evidence of the damage that air pollution inflicts on human health and warns that exceeding the new levels is associated with significant health risks.

Every year, around 7 million people die from air pollution, both outdoors and at home, according to WHO data. Pollution is a major environmental risk to public health globally. By reducing the levels of air pollution, stroke, heart disease, lung cancer, pneumonia, asthma and chronic obstructive pulmonary disease can be reduced.

Let's go from the beginning... what is the troposphere and how is it related to pollution?

Our planet is surrounded by a mass of gases divided into several layers according to their density. The thinnest and closest to the ground, where living beings are and meteorological phenomena occur, is the troposphere which has an altitude between 7 km, at the poles, and 17 km at the equator.

The entire atmosphere is dynamic, constantly moving around the Earth, changing its density and chemical composition depending on its altitude.

What we call dry air It is composed of 78% nitrogen, 21% oxygen and 1% argon, in addition to between 0.1 and 4% water vapor. It also contains "trace gases" such as carbon dioxide or methane and others created both by natural sources and by human action.

The composition of the troposphere changes continuously due to reactions that occur between the substances that compose it, giving rise to secondary pollutants harmful to our health and the environment.

What is air pollution?

In both developed and developing countries, air pollution represents a major environmental risk to health. It is understood by atmospheric pollution the existence of certain pollutants in the atmosphere in proportions that negatively affect human health, the environment and cultural heritage.

The origin of pollutants is both anthropogenic, that is, caused by human activity, and natural, due to volcanic eruptions, forest fires and sand storms. 

“Air pollution is estimated to have caused 4.2 million premature deaths worldwide in one year. This is due to exposure to particles smaller than 2.5 microns (PM25) that cause cardiovascular and respiratory diseases and cancer.”

World Health Organization (WHO), September 2021

 

The most frequent pollutants and their effects on our health

The suspended particles (PM) They are the most harmful air pollutant for health. These are particles so light that they can float in the air. Those with a diameter equal to or less than 10 microns (PM10) can penetrate and lodge in the deepest parts of the lungs, but the most harmful are those with a diameter equal to or less than 2.5 microns (PM25) and can cross the lung barrier and enter the blood system, just like oxygen. Continued exposure to these particles increases the risk of suffering from cardiovascular and respiratory diseasessuch as lung cancer.

These particles are made up of sulfates, nitrates, ammonia, sodium chloride, soot, mineral powders, and water.

A recent WHO study entitled "Review of evidence on health aspects of air pollution" concludes that long-term exposure to these particles can cause atherosclerosis, adverse in childbirth, respiratory diseases in childhood. It also speaks of a possible relationship with neurodevelopment, cognitive function and diabetes, and reinforces the idea that there is a close causal link between PM25 and deaths related to cardiovascular and respiratory problems.

El ozone (O3) In the stratosphere, one of the upper layers of the atmosphere, it protects us from ultraviolet radiation from the sun, while when it is present at ground level, in the troposphere, it is a major pollutant that is very harmful to human health and nature. 

It forms when sunlight reacts with pollutants such as nitrogen oxides (NOx) from vehicle or industry emissions, and volatile organic compounds (VOCs) produced by vehicles, solvents, and industry.

Its levels tend to be higher in summer and especially in the late morning and early afternoon.

The effects of ozone in high concentrations:

• corrodes materials, buildings and living tissue. 
• It reduces the ability of plants to carry out photosynthesis and prevents them from absorbing carbon dioxide. 
• weakens the reproduction and growth of plants. 
• causes inflammation of the lungs and bronchi, giving rise to pathologies such as asthma.

“Individuals most at risk for respiratory problems when ground-level ozone levels are high include children, the elderly, and those with asthma, congestive heart failure, coronary artery disease, and lung diseases such as COPD”

Michael Hernandez, MD Critical care pulmonologist affiliated with Baptist Hospital and South Miami Hospital.

In addition to ozone and PM, there are other worrying air pollutants. Vehicles, industries, power plants... need energy that is usually obtained by burning fuels. This causes many of the substances present in the atmosphere to change shape, giving rise to substances such as nitrogen dioxide (NO2) and ammonia.

The  combustion processes free others air pollutants, ranging from sulfur dioxide and benzene to carbon monoxide and heavy metals. Some of them can affect our health more or less immediately, while others accumulate in the environment, entering our food chain and reaching our plates.

Others, like the benzene, can damage the genetic material of cells and cause cancer. The burning of wood and charcoal produces benzo(a)pyrene (BaP), another cause of cancer, in addition to causing irritation of the eyes, nose, throat and bronchi.

 

 

How to reduce the risk of exposure

"Pollution affects everyone, both in developed and developing countries," says Marie-Eve Héroux of the World Health Organization's Regional Office for Europe.

 

Although pollution affects everyone, it does not harm us all to the same extent and in the same way. In urban areas the exposure is higher. In turn, the most vulnerable groups are those suffering from cardiovascular diseases and allergies that affect the respiratory tract, the elderly and infants.

According to the Aphekom project, air pollution in Europe reduces life expectancy by about 8.6 months per person.

To reduce the risk of exposure to these invisible gases, Dr Hernández recommends “paying attention to the Air Quality Index according to your geographical region. If it shows high levels, indicated in orange or red on the map, outdoor activities should be limited, especially those such as exercise or work that increases breathing. These days it is advisable to stay indoors, but if this is not possible, the use of masks is suggested to filter the air that reaches the lungs.

 

The threat inside the home: taking care of indoor air quality

Poor air quality is not only a concern outdoors, especially for those with cardiorespiratory problems.

Air pollution in closed spaces comes from sources such as chimneys, heaters, tobacco, construction materials, furniture, cleaning products, humidity, domestic animals and refrigeration systems, plus that which comes from outside.

Outside air can enter a closed space by infiltration, through cracks and crevices; natural ventilation, which consists of air that enters through an open window or door; and mechanical ventilation, which is produced in air conditioning systems or fans with outside air intake.

 

Some recommendations to improve air quality in indoor spaces are:

• Avoid smoking in enclosed spaces.
• Ventilate the house between 5 and 10 minutes a day.
• Check the gas installation periodically.
• Keep the fireplace clean and only burn dry, untreated wood in it.
• Avoid humidity.
• Use construction materials and furniture that produce low emissions.
• Install smoke and carbon monoxide alarms.
• Ventilate the space well when using detergents, cleaning products that emit chemicals into the air.

 

It is essential to take seriously the profound impact of air pollution and quality on our health. Together, each one from their place, we must address the issue and take the necessary measures to try to reduce air pollution that slowly and silently affects our health. 

 

 

To learn more about climate change, pollution and respiratory health, sign up for the 3rd Respiratory Patient Summit, an online event with international leaders and references.