Air pollution poses a significant threat to children's health, as exposure to harmful pollutants can lead to a range of developmental and respiratory issues. This article explores how pollutants such as particulate matter and nitrogen dioxide affect young bodies and minds, emphasizing the urgent need for effective environmental policies and protective measures.
Air pollution has been a global issue for quite some time. In October 1948, Donora, Pennsylvania, was enveloped in a haze, and for the next five days, people experienced severe cardiovascular and respiratory issues [5] . Since then, scientists have researched air pollution and its effects on human health. Policies and environmental acts have been rolled out to reduce the current air pollution and to prevent it from increasing. While there has been some success in reducing air pollution, it is still a significant issue affecting adults and children. Children are particularly vulnerable to air pollution because their bodies and minds are still growing. Early exposure to polluted air can have lasting impacts, causing immediate and long-term health issues.
Types and Sources of Air Pollution
Air pollution has several components that come from different sources. The major contributors are ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate matter [6] . Particulate matter is a tiny speck that is difficult to see with the naked eye, and its diameter ranges from 2.5 micrometers to 10 micrometers. With such small diameters, these particles can go deep into the lungs, affecting gas exchange. This matter comes from anthropogenic sources such as combustion, motor vehicle emissions, and industrial pollution. Sulfur dioxide occurs via oxidation of vehicle emissions in the atmosphere. Carbon monoxide is present due to poor-functioning combustion engines in older car models. Nitrogen dioxide comes from the burning of biomass and fossil fuel combustion. Lead is present in vehicle emissions and coal burning [9] .
Health Effects
Air pollution represents a significant risk factor in asthma development in children [12] . Asthma is a chronic inflammatory airway disease characterized by respiratory symptoms such as wheezing, dyspnea, cough, and chest tightness associated with variable expiratory airflow limitation. The prevalence of asthma is estimated to be between 1 and 18% of the population in different countries, depending on socioeconomic status and geographical location. Evidence suggests that 13% of the global incidence of asthma in children could be attributable to air pollution. A study of 3867 participants from the Dutch Prevention and Incidence of Asthma and Mite Allergy birth cohort was conducted to observe asthma development from birth into early adulthood. The researchers linked asthma incidence to estimated concentrations of nitrogen dioxide and particulate matter sizes 2.5, 10, and 2.5 absorbances at the residential address. Using discrete time-hazard models and adjusting for potential confounders, it was determined that a higher incidence of asthma until 20 years of age was linked to higher exposure to all air pollutants at birth address [8] .
Emerging research on air pollution's impact on children's cognitive development has shown that each type of air pollutant plays a role [11] . Nitrogen dioxide negatively impacts working memory, general cognitive functions, and psychomotor functions; Pm 2.5 is linked to difficulties in working memory, short-term memory, attention, processing speed, and fine motor functions. High concentrations of air pollutants are linked to changes in the brain's white matter or lower functional integration and segregation of children's brain networks. Furthermore, research has shown that exposure to air pollution can cause nervous system inflammation and oxidative stress, especially in fetuses and infants, which can cause permanent brain damage or lead to neurological disease in adulthood .[4]
Infants and children are susceptible to air pollution because their organs are developing and have higher air per body weight intake [1] . Due to this, they are more likely to experience adverse health effects such as respiratory disease, decreased lung function, and increased asthma. Children are also at risk of neurodevelopmental disorders, IQ loss, pediatric cancers, and increased risk for chronic disease as adults. These effects are mediated by oxidative stress, chronic inflammation, endocrine disruption, and genetic and epigenetic mechanisms across the life span. Indeed, as air pollution continues to be a global health burden, children with early-onset asthma are more likely to have persistent respiratory problems into later childhood and even adulthood. [2]
Despite the wealth of data on air pollution's impacts in countries such as the United States, there is a clear need for more research and data on air pollution impacts on children in low and middle-income countries with elevated air pollution levels. A 2023 study assessed cognitive development to determine if sex and urban/rural status modified pm2.5's association with cognitive delay. The findings revealed that urban-dwelling children had greater odds of cognitive delay than rural-dwelling children, but no significant difference by sex. This underscores the importance of further exploration of this topic in low and middle-income countries, highlighting the crucial role of research in shaping policy initiatives.
Mitigation and Policy Initiatives
Despite the rising air pollution, there is hope in the form of several policies and acts that have been implemented over the years. The 1990 Pollution Prevention Act, for instance, placed responsibility on the Environmental Protection Agency (EPA) to establish a source reduction program. This program aims to reduce the amount of any hazardous substance, pollutant, or contaminant entering any waste stream or otherwise released into the environment. The act established a national policy that emphasizes the potential for change.[7]
"Pollution should be prevented or reduced at the source whenever feasible;
Pollution that cannot be prevented should be recycled in an environmentally safe manner whenever feasible;
Pollution that cannot be prevented or recycled should be treated in an environmentally safe manner whenever feasible, and
Disposal or other release into the environment should be employed only as a last resort and should be conducted in an environmentally safe manner."
Other policies include the Clean Air Act, Emergency Planning and Community Right to Know Act, Resource Conservation and Recovery Act, and National Environmental Policy Act. Most policies addressing air pollution enacted by governments fall into three categories: (a) incentive policies, such as implementing a free public transportation program to reduce the use of private cars; (b) supportive policies, such as paying subsidies to change household fuels to more green sources, and (c) punitive policies, such as collecting tolls for cars to enter the congestion charging areas. Beyond policy, emphasizing greater use of renewable energy, clean fuels, and electric vehicles is vital in reducing air pollution.[10]
Conclusion
Air pollution comes in many forms and can affect everyone in similar ways. Sensitive populations such as children face a higher risk of adverse health outcomes as they are exposed to unsafe air conditions. Despite countless policies and efforts to reduce air pollution and prevent it from worsening, it is still a major environmental issue. It is up to policymakers to continue to support policies and interventions that help reduce the problem so children can grow up without increased risk of asthma and other adverse health outcomes due to air pollution.
