Pollution's Impact On Children's Health And Development

Air pollution is the largest environmental cause of disease and death in the world today, with 9 million deaths per year. It is a major cause of developmental disabilities, and children are particularly vulnerable to its effects. Exposures to even low levels of pollution during the first 1,000 days of life can stunt children's growth, increase their risk of disease, and cause lasting damage to their brains, lungs, reproductive organs, and immune systems.

Air pollution is linked to an increased risk of adverse pregnancy outcomes, including premature birth, low birth weight, intrauterine growth retardation, abnormal birth length, abnormal head circumference, and small size for gestational age. It is also associated with an increased risk of birth defects, including cardiac ventricular septal defects and aortic and pulmonary artery and valve defects.

Children exposed to air pollution are at a higher risk of respiratory infections, including acute lower respiratory infections, pneumonia, upper respiratory infections, and otitis media. It also exacerbates allergies, including allergic rhinitis, eczema, and conjunctivitis.

Air pollution affects lung function and development, increasing the risk of developing asthma. It is also linked to cognitive impairment and the development of some types of autism spectrum disorders. Exposure to traffic-related air pollution has also been associated with an increased risk of childhood leukaemia.

Given the vulnerability of children to air pollution and the serious health risks it poses, it is crucial to implement policies and interventions to reduce emissions, mitigate concentrations, and avoid individual exposure.

Air pollution and premature births

Air pollution is the largest environmental cause of disease and death in the world today. It is responsible for 9 million deaths per year – 16% of all deaths worldwide. Pollution is also a major cause of developmental disabilities, including injuries that impair children's health, diminish their capacity to learn, and reduce their lifetime earnings.

The dangers of air pollution during pregnancy

A mother's exposure to air pollution during pregnancy can injure her child's brain, diminishing their intelligence, shortening their attention span, and increasing their risk of attention deficit hyperactivity disorder (ADHD). Air pollution exposure in pregnancy increases the risk of premature births and low birth weight, which are two further risk factors for developmental disabilities.

How air pollution affects premature births

• Ozone exposure: Exposure to ozone during the second and third trimesters is significantly linked to preterm birth. Per interquartile range (IQR) increase in the second and third-trimester ozone exposure, the mean difference in term birth weight was −9.86 and −7.93 grams, respectively.
• Nitrogen dioxide exposure: Exposure to nitrogen dioxide during the first trimester is linked to an increased risk of gestational diabetes mellitus (GDM).
• Ozone exposure: Ozone exposure in the first trimester is connected to an elevated risk of gestational hypertension.

Reducing children's exposure to air pollution

Good progress has been made towards reducing air pollution from industry, transport, and homes, thereby reducing the number of deaths linked to air pollution overall. However, while ambient air pollution concentrations are decreasing in Europe, they continue to be unsafe, and 91% of the urban population is still exposed to air pollutant concentrations above the 2021 World Health Organization (WHO) air quality guidelines.

To protect children from the harmful effects of air pollution, it is important to reduce their exposure. This can be done by improving air quality around child-centric settings like schools and kindergartens, as well as during activities like school commutes and sports.

Air pollution and low birth weight

Air pollution is a major environmental health hazard, causing 9 million deaths per year globally. It is the leading environmental cause of disease and death worldwide, and it is getting worse in many parts of the world.

Children are particularly vulnerable to air pollution, and exposure during pregnancy and infancy can have serious consequences for their development. This is because their bodies and organs, including their brains and lungs, are still developing, and their immune systems are weaker than those of adults.

Effects of Air Pollution on Low Birth Weight

Air pollution, especially fine particulate matter, has been linked to an increased risk of low birth weight. Exposure to particulate matter during pregnancy can lead to acute inflammation in the lungs and other organs, including the placenta, which is associated with an increased risk of preterm labour and low birth weight.

Studies have found a direct and significant relationship between exposure to particulate matter and low birth weight. For example, a study in Ahvaz, Iran, found that exposure to particulate matter less than 10 micrometres in diameter (PM10) was associated with a 10 μg/m3 increase in the risk of low birth weight. Similarly, a study in Guangdong, China, found that exposure to PM10 during the first trimester of pregnancy was associated with a 3.9% increased risk of low birth weight.

Other air pollutants, such as sulphur dioxide (SO2) and nitrogen dioxide (NO2), have also been linked to low birth weight. A study in Sao Paulo, Brazil, found that exposure to SO2 was associated with an increased risk of low birth weight. Additionally, a study in China found that exposure to NO2 during pregnancy increased the risk of preterm labour and low birth weight.

Policy Implications

Given the well-established link between air pollution and low birth weight, it is crucial to implement policies to reduce air pollution and protect the health of pregnant women and their children. This includes reducing emissions from industry, transport, and residential heating, as well as improving air quality around schools and other child-centric settings.

It is also important to raise awareness among pregnant women about the negative consequences of air pollution and encourage them to avoid exposure to polluted air during pregnancy.

Air pollution and asthma

Air pollution is the largest environmental health risk in Europe and significantly impacts the health of children, who are more susceptible to the negative health effects of pollutants than adults. Children are disproportionately affected by the negative health effects of air pollution, which can cause an array of respiratory issues, including asthma.

Air pollution has been linked to an increased risk of asthma in children. In Europe, over 9% of children have asthma, placing a large burden on children, their families and societies. Asthma symptoms can range from mild to very severe, and even life-threatening. Exposure to short-term increases in air pollution increases the risk of asthma hospitalisation and emergency department visits for children.

Children are particularly vulnerable to air pollution, from when they are in the womb to when they reach adulthood. Their breathing rates are higher than those of adults, and they also inhale a larger fraction of air through their mouths. Their bodies and organs, including their lungs, are still developing, which further increases the risk of respiratory issues. Furthermore, children's immune systems are weaker than those of adults, strengthening the effects of pollution.

Both prenatal and postnatal exposure to traffic-related air pollution (TRAP) have been shown to negatively affect lung development and are linked to an increase in the prevalence of asthma and allergic disease. TRAP includes a collection of gases (nitrogen dioxide, sulfur dioxide, benzene) and particulates (particulate matter, black carbon) associated with fossil fuel combustion. Nitrogen dioxide is increasingly recognised as an important indoor and outdoor pollutant associated with the development of atopy, current wheezing, and lower forced expiratory volume in children. Recent studies have shown a link between nitrogen dioxide exposure and reduced lung function, increased need for rescue medications, and elevated risk and severity of asthma exacerbations.

Particulate matter exposure is implicated in multiple cardiopulmonary disease processes and is associated with premature death. Even short-term particulate matter exposures can be harmful, with one study showing a positive correlation between daily particulate matter concentration and pediatric asthma-related hospital visits.

Ozone is a by-product of photochemical smog. Both acute and long-term exposure to ozone is associated with negative pulmonary health effects, including lower lung function, increased asthma-related emergency department visits and hospital admissions, and more severe asthma exacerbations. Short-term ozone exposures during the months of August and September were positively associated with hospital admission for asthma among children, even after controlling for pollen and viral infections. Children are particularly susceptible, with a nearly 10% increase in the risk of emergency department visits for asthma for each interquartile range increase in ozone, with the largest effect found in 6–19-year-olds.

Reducing the impact of air pollution on asthma

Legislative efforts such as banning smoking in public spaces can be effective strategies for reducing the impact of this common pollutant on child health. Indoor tobacco legislation has been associated with a fall in asthma-related emergency department visits in children. However, these public smoking bans do not address the risks associated with parental smoking within the home.

Home interventions for improving indoor air quality have also been studied for their impact on respiratory health. For example, a study of asthmatic children living in homes with wood-burning stoves examined the impact of improved stoves and air filters on child health. The addition of air filters was associated with a reduction in indoor particulate matter levels and diurnal peak flow variability, which the authors used to approximate airway hyperreactivity.

Multiple studies around the world have demonstrated the benefit to child health of improved air quality. A longitudinal cohort study of US children from 1993 to 2012 found a significant association between decreases in ambient air pollutant concentrations in California and a reduction in cough and congestion symptoms in children with and without asthma. Ultimately, reducing the burden of pollutant-induced respiratory disease will require broad policy changes that reduce the burning of fossil fuels, increase urban green space, and mitigate the effects of climate change.

Air pollution and cognitive development

Air pollution is the largest environmental health risk factor for children, and it is estimated that 15% of all deaths of children under five are linked to it. Children are more vulnerable to the adverse health effects of air pollution because their bodies and organs are still developing, and they breathe in more air per kilogram of body weight. Their lungs are still developing, and air pollution can stunt their lung function and development.

A mother's exposure to air pollution during pregnancy can injure her child's brain, diminishing their intelligence, shortening their attention span, and increasing the risk of attention deficit hyperactivity disorder (ADHD). Exposure to air pollution during infancy and early childhood can also cause lung damage and lead to asthma, pneumonia, and chronic pulmonary disease.

In addition to respiratory issues, air pollution has been linked to cognitive impairment in children. Studies have shown that air pollution affects neurodevelopment, leading to lower cognitive test outcomes and negatively affecting mental and motor development. Children exposed to high levels of air pollution may also be at greater risk for chronic diseases such as cardiovascular disease later in life.

To protect children from the harmful effects of air pollution, it is crucial to improve air quality in schools, kindergartens, and other child-centric settings. This can be achieved by establishing clean air zones, siting new schools away from pollution sources, and enhancing indoor air quality through proper ventilation and filtration systems.

Air pollution and childhood cancer

Air pollution is a major contributor to the burden of disease worldwide. Most of the global population resides in places where air pollution levels, due to emissions from industry, power generation, transportation and domestic burning, considerably exceed the World Health Organization's health-based air quality guidelines.

Outdoor air pollution poses an urgent worldwide public health challenge because it is ubiquitous and has numerous serious adverse human health effects including cancer.

Children are particularly vulnerable to the adverse health effects of air pollution due to their higher minute ventilation, immature immune system, involvement in vigorous activities, the longer periods of time they spend outdoors and the continuing development of their lungs during the early postneonatal period.

There is substantial evidence from studies of humans and experimental animals, as well as mechanistic evidence to support a causal link between outdoor (ambient) air pollution, and especially particulate matter (PM) in outdoor air, with lung cancer incidence and mortality.

It is estimated that hundreds of thousands of lung cancer deaths annually worldwide are attributable to PM air pollution.

In addition to lung cancer, air pollution may also be associated with poorer cancer survival though further research is needed.

There is also some evidence linking radon and electromagnetic field exposure to pediatric cancer; however, the correlation is not strong, given the large amount of research demonstrating weak or negative relationships.

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