Air pollution and children's health

On September 7, we celebrate World Clean Air Day— a UN initiative that reminds us how closely our health is linked to the quality of the air we breathe. For children whose respiratory systems are still developing, air pollution poses a particularly serious risk.

As a long-time pediatrician and pulmonologist, Prof. Rada Markova, PhDdaily experiences the consequences of air pollution on the children's body — from frequent respiratory infections to chronic lung and allergic diseases. But behind diagnoses and clinical cases lies a deeper, systemic crisis—that of the environment in which our children grow and breathe.

Prof. Dr. Markovapresents a scientifically based, but accessible to parents and the public, view of the invisible but real threat of air pollutants. The subject does not tolerate postponement - because the health of our children is not a future issue. It's here and now.

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Air pollution and children's health

Assoc. D-r Rada Markova, MD

MC “First Children's Consultative Clinic” — Sofia

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Over the past 20 years, the problem of the “invisible enemy” — air pollution — has become more and more pervasive. The World Health Organization (WHO) calls it the “silent killer”. In the context of the COVID-19 pandemic, new data have come out on a higher incidence of coronavirus infection and mortality from it in areas with high atmospheric pollution (China - Wuhan; Lombardy - Italy).The greatest importance and future effect is that air pollution has on our children.

Essential for the development of a nation are programs for the prevention of chronic and socially significant diseases in childhood. In this sense, the problem of air pollution is particularly relevant and requires legislative and environmental measures in order to ensure the future and health of our children. The air we breathe every day is the same for everyone regardless of gender, race, age, social status and ethnicity.In big cities, we can only control its quality and take care of the environment in such a way that the harmful effects and consequences are minimal.

In recent years, the problem of air pollution has become very relevant especially for children — on the one hand, due to the incidence of acute and chronic diseases associated with air pollution, on the other hand — due to the longest impact that polluted air has on the adolescent organism in the case of prolonged exposure [1,2].

What makes children different?

• Closer location to sources of harmful emissions (car exhausts, dust, etc.)
• Higher respiratory rate and minute alveolar ventilation
• Game activity and increased physical activity
• Long exposure to atmospheric pollutant as an impact
• The pronounced sensitivity of the children's organism to atmospheric irritants.

Air pollution has different components: harmful gases, metals, dust particles, etc., which have different impacts on the health and development of children [3]. There is no organ or system that does not suffer from the effects of atmospheric pollutants.

What are the consequences for the children's organism?

A. Respiratory system:

The respiratory system (DS) is a major “filter” of much of the fine particulate matter (PMF) and toxic gases in polluted air. There are over 13,000 publications in Pubmed on the effects of DS from air pollutants. Respiratory organs suffer acute and chronic effects.

Children spend more time outside in active activities and sports. They have a not yet fully developed broncho-pulmonary system. Higher respiratory rate and mouth breathing are a risk factor for air pollutants entering the lower respiratory tract (DP) segments[4]. Due to the immature immune system, respiratory infections are more common. The consequences for the respiratory system (DS) can be acute and chronic and include: respiratory infections, increased reactivity of DP, irritation, inflammation of the broncho-lung structures, increased mortality from respiratory diseases, increased frequency of hospitalizations, decreased lung function (BP), development of bronchial asthma (BA) or exacerbation of an existing one, exacerbation of chronic obstructive pulmonary disease (COPD), increased risk of lung cancer, etc. [5,6].

Research has shown that the development of BF in children is impaired in areas with high PHC concentrations, with BP improving when children are moved to areas with lower air pollution or worsening when children move to higher pollution areas [7,8]. This impact on lung development is an additional risk factor for lung disease later in life. In a study of the long-term effects of air pollution on BP in children, it was shown that in urbanized areas a decrease in BP (measured by FEO1 and FVC), increased susceptibility to respiratory infections and the development of BA were found. Similar conclusions were drawn when studying the effects of atmospheric pollution on the incidence of respiratory infections in children from Hanoi, Vietnam with a significant correlation between nitric oxide levels and hospitalizations for pneumonias, bronchitis, and BA attacks in a given region.

Exposure to atmospheric pollutants can trigger the development of BA, lead to worsening of an already present respiratory disease, and provoke the development or progression of chronic diseases, including COPD, emphysema and lung cancer. Statistics show that the number of deaths from COPD has increased by more than 60% in the last 20 years, with air pollution being an important risk factor for the development of COPD [7,8]

Today's allergic children are different. Of key importance are: atmospheric pollution, stressful lifestyle, living in confined spaces, the role of new allergens.

Epidemiological studies have shown the increased incidence of rhinitis and asthma in urban settings. Pollutants stick to pollen and make it much more allergenic than uncontaminated pollens.

Modern children spend much more time in enclosed spaces, where allergens such as: house dust, animals, plants, mold, etc. play a role. The role of so-called “new allergens” such as ragweed is also noted. There is also an increase in food allergy to nuts, spices and exotic fruits. Stress may additionally, in an independent neuro-endocrine pathway, influence atopy.

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C. Cardiovascular System (CHS)

The impact of CCS can be direct or indirect. It is possible to change the autonomic function of the heart, to get myocardial infarction, angina pectoris, increased blood pressure, atherosclerosis, hypertension, increased incidence of ischemic heart disease, etc.

In recent years, numerous scientific evidence has emerged confirming the relationship between exposure to various atmospheric pollutants and the consequences for SSC, with acute and/or chronic effects [9]. Biological mechanisms linking air pollution to heart disease include both direct pollutant impacts on CCS, blood, and lung receptors, and indirect impacts mediated by pulmonary oxidative stress and inflammatory responses.

Direct effects can be carried out by agents easily penetrating through the pulmonary epithelium into the bloodstream. These direct consequences of air pollution represent a plausible explanation for the occurrence of rapid (within a few hours), cardiovascular reactions, such as an increase in cases of myocardial infarction [10].

Slower developing (from a few hours to days) and chronic indirect effects can occur through pulmonary oxidative stress or inflammation induced by inhaled pollutants.

Peak concentrations of the combination of PPH and nitric oxides correlate with an increase in the number of hospitalizations due to potentially fatal heart rhythm disturbances. Most often, such hospitalizations are due to ischemic heart disease and congestive heart failure.

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VILLAGE. Nervous system (NS)

Some components of atmospheric pollution have a pronounced “tropism” to the nervous system.

NS involvement can have the following clinical manifestations: developmental disorders of the NS, inflammation of neurons, oxidative stress, changes in the blood-brain barrier, headache, anxiety, stroke, Alzheimer's disease, Parkinson's disease, etc.

The mixture of components in air pollution also includes heavy metals, such as mercury or lead. Many of the heavy metals have a strong neurotoxic effect on the human body, especially in children [11].

Lead exposure in childhood can lead to a decrease in cognitive function, including reaction time, visuospatial abilities and executive functions in adults, i.e., cognitive flexibility and the ability to think abstractly. Lead exposure can also affect people's subsequent verbal memory and active vocabulary. A positive correlation with lead exposure was also seen in aggression, behavioral problems (such as depression and sleep disorders), and increased manifestations of antisocial and criminal behavior [12,13].

Mercury is a powerful neurotoxin that can seriously damage the brain and developing HS. Exposure to methylmercury in the womb can adversely affect the development of the baby's brain and CNS and lead to possible effects on cognitive thinking, memory, attention, speech, and fine motor and visual-spatial skills.

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E. Reproductive system (RS)

The involvement of RS can have the following clinical manifestations: impaired sperm quality, DNA fragmentation, low birth weight, premature birth, births at low gestational age, etc.

In developing embryos, the placenta serves as a barrier against many environmentally hazardous substances, but it cannot provide protection against all components of atmospheric pollution. Children are particularly susceptible to air pollutants even before they are born. Increasing evidence suggests that early exposure to atmospheric pollutants contributes to an increased risk of developing chronic diseases later in life, including obesity, diabetes and hormone-related malignancies.[14]. In addition, the latest research has established a correlation between exposure to atmospheric pollutants during pregnancy and low birth weight, as well as an increase in cases of preterm birth and preeclampsia.

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IS. Endocrine, metabolic and other effects

The harmful effects of atmospheric pollutants on glucose metabolism and an increased risk of developing type 2 diabetes have been proven. A statistically significant higher risk of developing neoplasms in children in areas with atmospheric pollution was also found [15]. In contaminants with radiation through the kidneys or accumulating in the liver, toxic hepatitis, nephritis and changes in the function of said organs can be observed.

At high levels of atmospheric pollution, evidence of osteoporosis has been established, as well as an increased risk of autoimmune diseases.

What is the role of pediatricians regarding air pollution problems?

• Active participation in public events for clean air.
• Prevention of exacerbation of chronic diseases in days and weeks with pollution by wearing masks, purifiers, limited physical activity.
• Training programs in kindergartens and schools on days with high levels of PMF and atmospheric pollutants.
• Work with children on reforestation of new areas and cleaning of kindergartens.
• Training of children and parents.

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Final messages

1. It is clear from the above that almost there is no organ or system in the human body that is not affected by atmospheric pollutants.Leading remains the involvement of the respiratory system, which “takes on” the greatest load of atmospheric pollution. The lung is a kind of filter of inhaled pollutants and also a main target organ for damage by them.
2. Studies continue to show a strong correlation of morbidity and morbidity in children from components of atmospheric pollution. ‍
3. Today and now we are the active people of the planet and we decide how our future — the children — will live.

Today, more than ever, we need shared responsibility — of institutions, politicians, the medical community, parents, educational circles and every citizen. An urgent change in priorities is needed: stricter environmental standards, real control of pollution sources, investment in urban greenery, sustainable transport and educational campaigns aimed at protecting the air.

Children cannot choose the air they breathe. What we do today will determine not only their health, but the health of our entire society tomorrow. Clean air is not a privilege — it is a right. And it's time to protect him.

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_{BIBLIOGRAPHY:}

_{1. Global Burden of Disease: http://www.thelancet.com/themed/global-burden-of-disease‍}

_{2. EU Commission 2013: http://ec.europa.eu/environment/air/index_en.htm}

_{3. WHO (2013). Review of evidence on health aspects of air pollution (REVIHAAP).}

_{4. DuBrowskia et al — Long — term exposure to ambient air pollution in childhood-adolescence and child function in adulthood — Advs.Exp.Medicine, Biology —Neuroscience and Respiration — 2018}

_{5. EEA (2014). Air quality in Europe — 2014 report}

_{6. WHO. The Environment and Health Information System (ENHIS) database.}

_{7. GAUDERMAN, W. J. ET AL. Association between air pollution and lung function growth in southern California children. Results from a second cohort. American journal of respiratory and critical caremedicine, 166:76—84 (2002).}

_{8. AVOL, EL ET AL. Respiratory effects of relocating areas or differing levels of air pollution. American journal of respiratory and critical care medicine, 164:2067—2072 (2001).}

_{9. GAUDERMAN, W. J. ET AL. Association between air pollution and lung function growth in southern California children. Results from a second cohort. American journal of respiratory and critical caremedicine, 166:76 —84 (2002).}

_{10. American Thoracic Society (ATS). What constitutes an adverse health effect of air pollution? American journal of respiratory and critical care medicine, 161:665 —673 (2000).}

_{11. EEA (2014). Air quality in Europe — 2014 report}

_{12. EEA (2014). Costs of air pollution from European industrial facilities 2008—2012 — an updated assessment}

_{13. HEAL (2013). The Unpaid Health Bill - How do coal power plants make us sick?}

_{14. The OECD Environmental Outlook to 2050. The consequences of inaction}

_{15. International Agency for Research on Cancer (WHO) :Outdoor air pollution is a leading environmental cause of cancer deaths:}

_{16. Plana operacional para exceedendo los normes especificada ou thresholds de de polluciones en aire atmosferico en otros faktoros en la território de Sofia Municipality — Sofia, 2017.}

_{17. Air pollution recovery in Bulgaria — facts, data and recommendations — HEAL 2014}