Environmental Issues in Global Pediatric Health: Technical Report

Pediatricians and pediatric trainees in North America are increasingly involved in directly providing clinical care to children and adolescents in low- and middle-income countries (LMICs). North American pediatricians also care for children who have emigrated from across the globe,¹; their number may increase in future years in consequence of climate change,² armed conflicts, complex sociopolitical circumstances, and changing immigration policies.³ 

Pediatric educators have come to recognize the great value of global health experiences.^4,5 Clinical and educational experiences in LMICs increase trainees’ appreciation of the importance of social and economic factors in shaping patterns of health and disease in children. They enhance trainees’ ability to operate across cultural and linguistic divides and provide competent, compassionate care in low-resource settings. To support global health training programs and enrich their curricula, the American Academy of Pediatrics (AAP) and the American Board of Pediatrics have jointly developed a comprehensive guide for education in pediatric global health.⁶ The AAP Section on International Child Health (currently named the Section on Global Health) released a policy statement titled “The Role of Pediatricians in Global Health.”¹ 

Environmental hazards are major causes of disease and death among children in LMICs, but the great magnitude of environmental impacts on children’s health in these countries is not generally appreciated.^7–9 In LMICs, environmental hazards account for twice as great a proportion of deaths in children younger than 5 years as in high-income countries—26% versus 17%.¹⁰ Pollution is a major risk factor and is responsible for an estimated 9 million deaths annually in persons of all ages—3 times as many deaths as AIDS, tuberculosis, and malaria combined. Nearly 92% of pollution-related deaths occur in LMICs.¹¹ Environmental threats to children’s health in LMICs are worsening, and ambient air pollution and contamination by pesticides and other toxic chemicals are growing especially rapidly.

It is important that pediatricians, pediatric trainees, and other pediatric health professionals from high-income countries who plan to work in LMICs be aware that toxic environmental exposures account for a much higher proportion of disease, disability, and death among children and adolescents in these countries than among youth in high-income countries. It is important also that they become knowledgeable about the major environmental threats to children’s health in the countries and communities where they will be working and incorporate this information into their clinical practice. Similarly, it is important that pediatricians in high-income countries who care for children and adolescents who have emigrated from LMICs be aware that these patients may be at elevated risk of diseases caused by past exposures to toxic environmental hazards in their countries of origin as well as ongoing exposures in products such as traditional foods, medications, and cosmetics imported from their home countries.

This technical report provides an overview of key environmental issues in global pediatric health with a particular focus on toxic chemical hazards. The goals are to increase awareness of the great impacts these hazards on children’s health both among pediatricians who may be directly providing care to children in LMICs as well as among pediatricians in North America who may be caring for children who have emigrated from LMICs. The report provides summary reviews of the major environmental hazards in LMICs and a listing of resources for further information.

The goal of this technical report, along with the accompanying policy statement,¹² is to enhance pediatricians’ ability to recognize, diagnose, and manage disease caused by hazardous environmental exposures, especially toxic chemical exposures, in all countries and especially in LMICs.

The twin concepts of the “environmental risk transition”¹³ and the “epidemiological transition”¹⁴ provide a useful framework for understanding how environmental threats to children’s health vary across countries and how these threats change as countries develop. In the world’s poorest, least developed countries, the prevalent environmental hazards are the ancient scourges of household air pollution and water pollution. Household air pollution arises mainly from the combustion of biomass fuels—wood, straw, dung, and charcoal—in poorly ventilated home cook stoves.¹⁵ Household air pollution is responsible for nearly 570 000 deaths each year in children younger than 5 years, mainly from lower respiratory tract infections.¹⁰ Water pollution accounts for 360 000 deaths annually in children younger than 5 years, mainly from diarrheal diseases.¹⁰ Malnutrition magnifies the impacts of these exposures.

As countries develop, urbanize, industrialize, and become integrated into global supply chains, patterns of environmental exposure change. This is termed the “environmental risk transition.”¹³ In this transition, countries move from biomass to cleaner fuels, and the traditional hazards of household air pollution and contaminated drinking water are replaced by ambient air pollution, toxic chemical pollution, and hazardous waste exposures.¹⁶ An important driver of this transition has been the relocation in recent decades of nearly two-thirds of the global chemical manufacturing industry to LMICs.¹⁷ 

As countries develop, patterns of disease in children change.¹⁸ This is the “epidemiological transition”¹⁴ and it parallels the environmental risk transition. In the epidemiological transition, deaths from pneumonia and diarrheal disease decline, infant mortality plummets, and life expectancy increases. In Africa, for example, infant mortality has decreased by almost 75%—from 187 deaths per 1000 live births in 1950 to 51 per 1000 today, and in the same time, life expectancy has nearly doubled—from 36.5 years to 64.1 years.¹⁹ Drivers of the epidemiological transition include the introduction of cleaner fuels,¹⁵ increased access to safe drinking water, the dissemination of pneumococcal vaccine and rotavirus vaccine,²⁰ the introduction of new treatment protocols such as oral rehydration therapy,²¹ improved infant nutrition,²² and enhanced access to medical care.

In the aftermath of the environmental risk and epidemiological transitions, noncommunicable diseases (NCDs)—asthma, birth defects, cancer, neurodevelopmental disorders, diabetes, obesity, and disorders of reproduction—replace infectious diseases as the major causes of disease and death in children.^19,23 Even in LMICs where they were previously rare, pediatric NCDs have now become common.^19,24 The once very separate patterns of disease and death in low-, middle-, and high-income countries are converging.²⁵ Children in many LMICs today suffer a double burden of environmentally attributable disease that reflects their simultaneous exposures to both traditional and more modern environmental hazards.^18,26 

The environmental risk and epidemiological transitions have taken place at different times in different countries. High-income countries such as the United States and Canada went through their transitions in the late 19^th and early 20^th centuries. Many LMICs are in transition now, and different countries and even different regions within countries are at various stages of transition. Accordingly, patterns of disease vary greatly from country to country and from region to region. Some of the sharpest contrasts are seen between rural and urban areas within LMICs.

Significant social, ethnic, racial, and economic inequities are evident in the global distribution of environmental hazards. Nearly 92% of all disease and death attributable globally to environmental risk factors occurs in LMICs.¹¹ In countries at every economic level, disease caused by hazardous environmental exposures is most prevalent among poor people and historically marginalized groups, an inequitable pattern of exposure and disease termed “environmental injustice.”²⁷ 

Environmental injustice is seen also in high-income countries, including the United States. Examples include the disproportionate siting of polluting industries, hazardous waste sites and major roadways in low-income communities where the majority of the residents are people of color. Another example is the disproportionally high levels of lead found in drinking water in communities comprising predominantly people of color, such as Flint, Michigan. The disproportionate exposures of Native American and Alaska Native children to high levels of household air pollution and unsafe drinking water are further examples of environmental injustice in the United States.^28–30 

In LMICs, disparities based on social class, economics, race, and ethnicity can shape the environmental risk and epidemiological transitions.^11,18,24 Some countries, notably middle-income countries with effective central governments and fairly equitable distributions of resources, have largely completed their epidemiological transitions and have increased the well-being of families across the economic spectrum. Some countries are passing through the transition now. In still other countries, typically the world’s lowest-income and most economically unjust and politically corrupt nations, the transition has not yet begun, and infectious diseases remain the predominant causes of disease and death in children.

The “off-shoring” of hazardous industries from high-income countries to LMICs where wages are low and environmental protections and the health infrastructure are often weak—so-called “pollution havens”—contributes to the disproportionate concentration in these countries of toxic pollution and diseases caused by hazardous environmental exposures. The disproportionate distribution of these hazards may be expected to become still greater in future years with increasing globalization of supply chains.^31,32 

Disease, disability, and death caused by toxic environmental exposures result in large economic and social costs in all countries, and especially in heavily polluted LMICs (Table 1). These include health care costs as well as increased costs for special education, accommodation for disabilities, and other developmental services. In addition, environmentally related disease and disability have negative economic impacts on children’s futures because they diminish children’s educational attainment, their lifelong learning potential, and their ability to contribute to society by reducing cognitive function, decreasing IQ, and impairing physical function.¹¹ The economic losses caused by disease of environmental origin are so massive in heavily polluted LMICs that they can undercut these countries’ ability to develop and to invest in children’s health, education, and social welfare,^33,34 thus perpetuating the cycle of poverty.

Hazardous environmental exposures and the diseases they cause are the result of human activity and can, therefore, be prevented. This is a key point, and it is the basis for all pollution control policy. The strongest evidence that diseases of environmental origin can be prevented is seen in the experience of the United States and other high-income countries in controlling pollution and preventing pollution-related disease.¹¹ In the United States, for example, air pollutant emissions have been driven down by 77% since passage of the Clean Air Act in 1970,³⁵ drinking water is now cleaner, polluted rivers no longer catch fire, and the worst hazardous waste sites have been remediated. Disease and premature death of environmental origin have been prevented and tens of thousands of lives have been saved.³⁵ 

Prevention of environmental hazards requires a combination of research to discover the environmental causes of disease coupled with evidence-based advocacy that translates research findings into policies and prevention programs. Pediatricians are trusted advisors, uniquely well qualified to address environmental threats to children’s health and to advocate for prevention of children’s exposures to environmental hazards. Successful prevention efforts in environmental health, many of them led by pediatricians, have included:

• Removal of lead from automotive gasoline, which resulted in a more than 95% reduction in blood lead levels of American children and an approximate 5-point gain in population mean IQ.³⁶ Every country around the world has now removed lead from automotive gasoline.

• A ban on production of polychlorinated biphenyls (PCBs) that was incorporated into the Toxic Substances Control Act.³⁷ This has resulted in reductions of PCB levels in children’s blood and reduction in the number of children suffering from PCB-induced loss of intelligence.

• Elimination of residential uses of organophosphate pesticides, such as chlorpyrifos, with subsequent reductions in the numbers of infants born with lower birth weight and small head circumference caused by prenatal exposure to chlorpyrifos.³⁸ 

• Reduction in children’s exposure to arsenic in drinking water with subsequent reduction in risk of skin and liver cancer.^39,40 

• Reduction in rates of childhood asthma and improvement in lung function following reduction in children’s exposure to urban air pollution and widespread education about the hazards of second-hand tobacco smoke, cooking fumes, cockroach droppings, and other indoor air pollutants.⁴¹ 

Prevention of diseases caused by hazardous environmental exposures has not only improved children’s health and well-being, but also created economic benefits.³⁵ Examples include the great economic gains that have resulted from reductions in air pollution⁴² and from removal of lead from gasoline.³⁶ Information on the cost-effectiveness of disease prevention programs provides pediatricians with another powerful argument for persuading policy makers to take preventive action to safeguard children’s health.^36,42 

Contaminated water is a major source of disease and death among children in LMICs.¹¹ It is responsible for an estimated 360 000 deaths annually in children younger than 5 years. Water supplies in LMICs can be contaminated by biological waste (human and animal) and also by chemical waste. In rural areas and in the least developed countries, biological contamination predominates, but as countries develop and industrialize, chemical pollution becomes increasingly important. Some of the worst pollution of drinking water is seen in and around the megacities of rapidly industrializing LMICs, where local waterways and groundwater are heavily polluted by both biological waste and chemical discharges, and there are no alternative water sources.⁴³ Treatments that control infectious agents are generally not effective in removing toxic chemicals from drinking water.

Substantial progress has been made in reducing water pollution globally. Between 1990 and 2015, 2.6 billion people worldwide gained access to improved drinking water sources, and 2.1 billion people gained access to improved sanitation. In this time, the number of children dying from diarrheal diseases decreased by almost 60%. However, despite this progress, 2.4 billion people are still using unimproved sanitation facilities, including 946 million people who still practice open defecation.¹¹ 

The principal diseases linked to water pollution are acute and chronic gastrointestinal tract diseases—diarrheal diseases, typhoid fever, and paratyphoid fever.⁴⁴ Polluted water and inadequate sanitation are linked additionally to a range of parasitic infections. These diseases affect more than 1 billion people worldwide, predominantly in LMICs.^44,45 Large numbers of deaths are seen also in some Southeast Asian countries. In the past 2 decades, China has greatly reduced mortality from waterborne infectious disease.⁴⁴ These burden-of-disease data do not adequately reflect disease and death caused by chemical pollution of water, because data on levels of chemical contamination of drinking water are not available for most LMICs, patterns of exposure have not been mapped, and the potential toxicity of many chemical pollutants has never been assessed.⁴⁶ 

Household air pollution (HAP) and ambient air pollution are major sources of disease and death in children worldwide, and especially in LMICs.¹¹ HAP and ambient air pollution are both products of combustion and thus originate from the same sources—coal, oil, natural gas, and biomass fuels—as the carbon dioxide that drives global climate change. HAP and ambient air pollution contain many of the same chemical constituents, and they often coexist and exert synergistic effects. Fine particulate pollution comprised of airborne particles of median diameter of 2.5 microns and below (PM_2.5 pollution) is the most extensively studied form of air pollution.

Burning of biomass and solid fuels in unvented indoor stoves for cooking and heating is the major source of HAP. HAP concentrations inside poorly ventilated homes in LMICs can reach exceedingly high levels. Women and young children are disproportionately exposed to HAP because of traditional gender roles involving cooking and food preparation in many LMICs placing women and their children in close and prolonged proximity to polluting stoves.^15,47 

Many LMICs are experiencing large increases in ambient air pollution today as they develop economically and industrialize.¹¹ These increases are driven by increased combustion of coal and other fossil fuels for the generation of electricity and other industrial activities as well as by growing car ownership. Wildfires contribute additionally to particulate matter pollution, and air pollution from this source will likely increase as climate change increases the frequency and scale of wildfires.⁴⁸ The World Health Organization (WHO) compiles information on PM_2.5 concentrations from more than 1000 cities around the globe. This information indicates that LMICs generally have higher concentrations of PM_2.5 pollution than high-income countries, and shows that 88% of urban residents globally live in cities that fail to meet WHO air quality guidelines.⁴⁹ Children in LMICs are at greatly increased risk of adverse health effects from air pollution. Emerging evidence suggests that exposure to air pollution, including airborne particulate matter, can increase morbidity and mortality from SARS-CoV-2 infection (COVID-19).^50–53 

A projection of future trends in mortality associated with ambient PM_2.5 air pollution predicts that, in the absence of aggressive intervention, the numbers of air pollution-related deaths will rise sharply over the next 3 decades. Greatest increases will be seen in South and East Asia.⁵⁴ In the worst case scenario, these trends are anticipated to produce a more than 50% increase in the number of deaths attributable to air pollution by 2050.⁵⁴ Not included in this projection are likely increases in numbers of deaths attributable to pollution-related low birth weight and preterm birth.^55,56 

PM_2.5 air pollution from both household and outdoor sources is linked to a number of adverse health outcomes in children. In infancy, these include preterm birth, low birth weight, and intrauterine growth restriction.⁵⁷ The impacts of air pollution in children include increased incidence of lower respiratory infection, increased prevalence of asthma, increased frequency of acute asthmatic attacks, and impaired lung growth.⁴¹ Chronic exposure to PM_2.5 pollution in childhood may increase disk of cardiovascular disease, chronic obstructive pulmonary disease, and other NCDs in adult life.⁵⁸ Recent studies suggest associations between PM_2.5 pollution exposure during pregnancy and increased risk of impaired cognitive function,^59,60 attention deficit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD).⁶¹ All of the health impacts of air pollution fall very heavily on children in LMICs, especially on children in countries where concentrations of PM_2.5 and other air pollutants are orders of magnitude higher than those typically encountered in high-income countries.⁴⁹ 

Acute and chronic lead poisoning are problems of enormous importance for child health worldwide. Global consumption of lead is increasing because of rising demand for batteries and energy-efficient vehicles. An estimated 40% of the world’s children have blood lead levels exceeding 5 μg/dL, and 90% of these children live in LMICs.⁶² Patterns and sources of exposure to lead (Table 2), prevalence rates of lead poisoning, and the severity of outcomes vary greatly from country to country. Countries with strong prevention programs have imposed bans on certain uses of lead, have set environmental standards, and have deployed screening programs. Lead “hot spots” are common in LMICs; these include battery recycling operations, smelters, mines, hazardous waste sites, and sites where hazardous waste is burned.⁶³ 

Mercury is a highly toxic metal. It occurs in the environment in several forms, of which methylmercury is the most hazardous. Methylmercury, an organic form of mercury, is a potent developmental neurotoxicant. Human exposure to methylmercury is of great concern, especially exposures occurring in utero during pregnancy. Methylmercury crosses the placenta, passes easily into the tissues of fetuses and young children, and causes permanent injury to the developing brain.⁶⁴ 

Polluting industries are the main source of mercury emission to the environment.⁶⁵ Four industries are especially problematic:

• Coal-burning electricity generation plants are the major global source of mercury emission, as all coal contains mercury. When coal is burned, microscopic droplets of metallic mercury are released into the air and eventually reach rivers, lakes, and oceans. Metallic mercury is converted to methylmercury in the aquatic environment and enters the marine food chain.

• Waste incinerators, including hospital incinerators, which, like coal-fired power plants, release metallic mercury to the atmosphere.

• Chloralkali facilities that use metallic mercury as a catalyst to produce chlorine gas.

• Artisanal and small-scale gold mining (ASGM) operations that use metallic mercury to form an amalgam to separate gold from ore. ASGM operations release mercury to the environment through vaporization and also through runoff of spilled mercury into waterways.⁶⁴ Most ASGM operations are located in LMICs.

Consumption of fish contaminated by methylmercury is the major route of human exposure.^64,66 Methylmercury concentrates as it moves up the food chain to reach very high levels in the predatory fish at the top of the chain, such as tuna, mackerel, and striped bass, as well as marine mammals consumed by humans in the circumpolar regions.⁶⁵ Children and adolescents in fishing communities in LMICs and in Indigenous communities whose traditional diets are rich in fish and marine mammals are at especially high risk of exposure to methylmercury in seafood.⁶⁷ A 2019 AAP technical report details the benefits and risks associated with fish and shellfish consumption.⁶⁸ In addition, individuals can be exposed to elemental or inorganic mercury from its use in rituals and folk remedies including Santeria (Cuba), Voodoo (Haiti), Espiritismo (Puerto Rico), and Ayurvedic medicine (India).⁶⁹ 

Arsenic is a metalloid element that occurs naturally in the earth’s crust. It is also released into the environment by polluting industries such as mines and ore smelters. Near such industries, inhalation is an important exposure route. Worldwide, drinking water is the principal source of arsenic exposure, especially in areas with high levels of naturally occurring arsenic in bedrock that leaches into ground water accessed by small wells (eg, in areas of Bangladesh, Chile, Argentina, the southwestern United States, and northern New England). Children born to mothers who reside in such areas during pregnancy are at risk of exposure in utero. Children can also be exposed to arsenic through ingestion of contaminated soil—eg, soil contaminated by industrial activity or agricultural land contaminated by current or past use of arsenic-containing pesticides. Further, given that rice plants can uptake and accumulate arsenic from the soil, food can be a significant source or arsenic exposure, especially in children who eat rice-centered diets.^70,71 

Chronic exposure to inorganic arsenic is associated with several human cancers, including lung, bladder, and skin cancer.⁷² Prenatal exposures to arsenic in drinking water have been linked to increases in late fetal, neonatal, and postneonatal mortality as well as to neurodevelopmental abnormalities, pediatric and adult cancers, and bronchiectasis.^40,73,74 Lifetime risks of lung and bladder cancer are 2 to 4 times greater among children whose exposure to arsenic begins in early life than among children whose exposures that begin later in childhood or in adult life.⁷⁵ 

Global production of industrial chemicals and plastics has grown dramatically in the past half-century, and children’s exposures to synthetic chemicals have become a focus of great concern in environmental pediatrics. More than 350 000 new synthetic chemicals and pesticides have been invented since 1950.⁷⁶ Most did not previously exist in nature. These manufactured chemicals are now used in millions of consumer products and have become extensively disseminated in the global environment. Only a minority have ever been tested for safety or potential toxicity.⁴⁶ As is documented by the Centers for Disease Control and Prevention (CDC)’s National Biomonitoring Program, children’s exposure to these largely untested chemicals is almost universal.⁷⁷ 

With globalization of trade, toxic chemicals that previously were used only in high-income countries are entering LMICs in ever-increasing volumes.¹⁷ Nearly 70% of global chemical and pesticide production now takes place in LMICs.⁷⁸ Most new growth in global chemical production is occurring in LMICs, much of it concentrated in so-called “pollution havens” where labor costs are low and environmental and public health protections are often few.⁷⁹ 

Catastrophes involving chemical exposures have resulted and have caused disease and death in children in LMICs, including the following:

• Bhopal catastrophe: In 1984, a massive explosion occurred in a poorly maintained chemical plant in Bhopal, India. Large quantities of highly toxic, methyl isocyanate gas were released and spread across the city. Hundreds of persons died, including many children, and tens of thousands suffered permanent injury.⁸⁰ The plant had been transported to India from the United States.

• Asbestos: More than 2 million tons of newly mined asbestos are exported each year to LMICs. Russia is the major producer. The material is widely used in the construction of homes and schools. The resulting exposures to persons of all ages will result in epidemics of lung cancer and malignant mesothelioma that extend over much of the century.⁸¹ 

• Lead: Recycling of used lead-acid batteries takes place in virtually all LMICs. Battery recycling often takes place in “backyard” establishments in close proximity to homes and schools. Multiple episodes of pediatric lead poisoning have been documented to result, some of them extremely severe and even fatal.⁸² 

• Mercury: Mercury poisoning from artisanal and small-scale gold mining is a major global hazard.⁸³ 

• Electronic waste (e-waste): An estimated 45 million tons per year of e-waste are shipped each year into LMICs.¹⁶ Thousands of women and young children are employed in e-waste recycling and are exposed to mixtures of heavy metals, flame retardants, toxic products of combustion, and other chemicals during the recycling process.

• Polybrominated diphenyl ethers (PBDEs): PBDEs are chemical flame retardants that were extensively added to electronics, building materials, and other consumer products. Despite a global phase-out for use in new products, the environmental persistence and lipid bioaccumulation of PBDEs contributes to an ongoing exposure risk through contaminated soil, dust, and fatty foods (eg, fish, meat, dairy). Individuals involved in e-waste recycling, especially through village-based recycling processes, can be exposed to large amounts of PBDEs.^84,85 Exposure to PBDEs has been linked to cognitive deficits in children⁸⁶ and disruption of the endocrine system, including thyroid hormones.⁸⁷ 

• Per- and poly-fluoroalkyl substances (PFAS): PFAS (the “forever chemicals”) are a class of synthetic chemicals that have been widely utilized by industry because of properties such as heat-resistance, stain-resistance, and friction reduction. They are found in products such as food packing, nonstick cookware, and firefighting foam. PFAS are extremely persistent in the environment and have been found across the globe in water, soil, and dust, and nearly universal human exposure has been documented.^88,89 Emerging evidence has linked PFAS exposure to a range of health effects such as high cholesterol, alterations in thyroid and liver function tests, lower birth weight, immunotoxicity, and cancer (kidney, testicular).^90,91 

• Phthalates: Phthalates are plasticizers added to plastic products, polyvinyl chloride (PVC), and cosmetics in the amount of millions of tons annually. They migrate easily out of products and lead to human exposure through inhalation, ingestion, and skin absorption. Phthalates exposure is associated with obesity, type 2 diabetes mellitus/insulin resistance, alterations in thyroid function, and adverse reproductive system impacts. These compounds have also been linked to increased risk of allergy and asthma as well as neurodevelopmental delays.⁹² 

Pesticides are potent molecules specifically designed to kill living organisms. They include insecticides, rodenticides, fungicides, and herbicides. More than 700 unique pesticide chemicals and thousands of commercial formulations are currently on world markets. Several billion pounds are used annually. Approximately 75% of current global pesticide use is in LMICs. The sale and widespread use in LMICs of highly toxic pesticides that are banned in the United States and Western Europe poses a growing threat to children’s health.^93,94 

Pesticide use has evolved over time. Some highly toxic and environmentally persistent older pesticides such as lead arsenate, dichloro-diphenyl-trichloroethane (DDT), and lindane have been largely phased out. However, use of newer pesticides such as the pyrethroid insecticides and the neurotoxic neonicotinoid insecticides have increased sharply.

The herbicide glyphosate (marketed as Roundup), the world’s most widely used herbicide, has become a chemical of particular concern. Global use of glyphosate has increased more than 10-fold in recent decades. Use is increasing very rapidly in LMICs as these countries adopt industrialized farming technologies to produce commodity crops such as genetically modified organism (GMO) corn and soybeans for world markets.⁹⁵ Glyphosate was long considered a relatively innocuous chemical. In 2015, however, the International Agency for Research on Cancer, the cancer agency of the WHO, determined on the basis of extensive review by international experts that glyphosate is “probably carcinogenic to humans.”⁹⁵ Glyphosate exposure is associated with non-Hodgkin lymphoma.⁹⁷ 

Pesticides can cause both acute poisoning and chronic toxicity in children. An estimated 99% of all acute pesticide poisonings occur in LMICs. Children in LMICs are at very high risk of acute pesticide poisoning because of their potential exposure to highly toxic pesticides no longer used in high-income countries, labels that are not printed in local languages, low literacy, inadequate training of pesticide applicators,⁹⁸ and storage of pesticides in unsafe containers such as soda bottles.⁹⁹ It is important that pediatricians and pediatric trainees working in LMICS be able to recognize and treat pesticide poisoning and be able to provide guidance on how to reduce pesticide exposures.

Electronic waste (e-waste) disposal sites containing discarded electronic devices and their components represent a relatively new and rapidly growing type of hazardous waste site in countries around the world.¹⁶ More than 45 million tons of e-waste is generated globally each year,¹⁶ and this volume is expected to increase in coming years. Significant amounts of e-waste are exported from high-income countries to LMICs where recycling of valuable compounds from e-waste, such as copper and gold, has evolved into an important business, predominantly in home-based and village-based industry.¹⁰⁰ 

E-waste contains a vast number of hazardous chemicals, including lead, cadmium, mercury, nickel, barium, and lithium as well as persistent organic pollutants, such as PCBs and brominated flame retardants. Unsafe recycling activities, such as open burning and acid leaching of e-waste, produce toxic combustion products including dioxin-like PCBs and polychlorinated dibenzo-dioxins and dibenzo-furans.¹⁰¹ 

Young children and pregnant women are often employed at e-waste disposal sites, and e-waste poses significant health risks to child workers.⁸⁵ Children may also encounter hazardous substances through take-home exposures and home-based e-recycling workshops. Children at e-waste sites have been reported to display elevated levels of multiple toxic chemicals, including lead and nickel.¹⁰² These exposures are associated with a range of adverse health effects, including injury to children’s immune, cardiovascular, gastrointestinal, renal, endocrine, and hematological systems; and adverse birth outcomes.^16,103 

The main driver of global climate change is increasing release into the atmosphere of carbon dioxide (CO₂), methane, and other long-lived greenhouse gases that trap heat energy.¹⁰⁴ Human activity is the main source of greenhouse gas emissions. The consequences of rising CO₂ levels include rising temperatures at the surface of the earth, sea surface warming, glacial melting, rising sea levels, increased frequency of violent storms, increased frequency of floods and droughts, increased frequency of heat waves, increased frequency of wildfires, and expanded geographic ranges of vectorborne diseases, such as malaria and dengue, and waterborne diseases, including cholera.¹⁰⁴ 

Each of the consequences of global climate change has myriad impacts on children’s health. These health effects of climate change have been extensively reviewed^105,106 and are addressed in a statement from the AAP focused on climate change and children’s health.^107,108 Therefore, these are considered only briefly here.

A key consideration in the context of this report is that the health impacts of climate change fall most severely on children in LMICs. Children in LMICs who have underlying health conditions and have limited access to essentials necessary for life will be least resilient and most severely affected. Climate change has potential to magnify the impacts on children’s health of other hazardous environmental exposures.¹⁰⁹ 

The impacts of climate change on child and adolescent health can be divided into direct and indirect effects (Table 3).⁷ Sustained high temperatures, air pollution, infectious diseases, and extreme weather and natural disasters will directly affect health. Climate change will also reduce agricultural yields and thus create food shortages; decrease access to clean water, increase social unrest, and trigger migration and war, all of which, in turn, may endanger child health and welfare. The pediatric community can play a critical role in addressing climate change, explaining the connections between climate and child health to policy makers and the public and advocating for the protection of children’s health against climate-related hazards.

Child labor is defined as “work that deprives children of their childhood, their potential and their dignity, and that is harmful to physical and mental development.”¹¹⁰ Child labor can lead to dangerous environmental exposures such as pesticides and organic dusts in agriculture¹¹¹; lead and other toxic metals from smelting, battery recovery, and mining¹¹²; and solvents from cleaning or leather tanning activities.¹¹³ It is linked to multiple adverse physical, developmental, emotional and behavioral outcomes.¹¹⁴ Hazardous child labor conditions have also been documented in the United States (eg, agriculture work among young migrant Latinx children).¹¹⁵ Although a critical global health issue, child labor goes beyond the scope of this report, and interested providers are encouraged to review available resources.^{110,113,114,116} 

Each day, approximately 2000 children globally die from unintentional injuries such as road traffic injuries, drowning, fire-related burns, falls, and poisonings. More than 95% of these deaths occur in LMICs.¹¹⁷ Within LMICs, children facing chronic poverty, conflict, or displacement are at greatest risk.¹¹⁷ Of particular concern are road traffic injuries, which are the leading cause of death for persons 5 to 29 years of age in LMICs.¹¹⁸ Many childhood and adolescent injuries do not lead to death but can have serious sequelae. Head injuries are the most common nonfatal child injury and the most severe type of injury sustained by children around the world. Many children who suffer head injuries and other types of trauma are left with disabilities.¹¹⁷ In LMICs, there is limited public health funding and infrastructure dedicated to injury prevention or to rehabilitation.¹¹⁷ 

Many types of environmental pollution affect the health of communities living far from their points of origin. A prime example of such “transboundary” exposure is ambient air pollution (see section “Ambient Air Pollution”). Air pollutants such as fine particulate matter (PM_2.5) can be transported long distances in the atmosphere across regions and continents. A study found that 12% of the 3.45 million deaths attributable to PM_2.5 in 2007 were attributable to pollutants emitted in another region of the world.¹¹⁹ Similarly, chemical and biological water pollutants can travel downstream, crossing jurisdictional boundaries within rivers, aquifers, lake basins, and marine ecosystems. Depletion of aquifers, construction of large dams, and climate change further impact the availability and quality of water in LMICs.¹²⁰ 

The international trade in toxic products, both through official and illegal mechanisms, poses disproportionate risk to communities in LMICs. Although multinational agreements regulate some international trade of chemicals, illegal trafficking of hazardous products remains widespread. Pesticides are a common entity in this illegal market, and agricultural workers and their children are at particular risk from dangerous exposures to banned pesticides such as aldicarb, paraquat, and parathion. Mercury is informally imported into LMICs that engage in ASGM.¹²¹ Families in high-income countries such as the United States can be exposed to toxic chemicals in products imported from LMICs, including cosmetics, amulets, ceramics, religious powders, and pesticides.^122,123 

Informed suspicion is key to the correct diagnosis of disease in children and adolescents caused by hazardous exposures in the environment.¹²⁴ The alert clinician needs to be open to the possibility that any child or adolescent may have an illness caused or exacerbated by an environmental exposure. Because diseases of environmental origin in children seldom have unique physical signatures, an exposure history, supplemented by laboratory testing, is the principal diagnostic tool. A targeted environmental history is an important part of pediatric care during well visits, management of an environmentally related illness (eg, asthma), and the diagnostic assessment of a new illness.¹²⁵ It is important that the environmental history include questions about the home, neighborhood, and other places the child spends time; these questions can be tailored to reflect the most prominent environmental exposures in a particular community and country.⁶⁹ It is important to use a qualified interpreter in every patient encounter in which English is not the family’s first language.

The WHO provides clinicians with a pediatric environmental health history tool, the “Green Page,” to assist in the identification of critical environmental exposures.¹²⁶ This tool is especially important for providers who are practicing outside the United States, as it includes key issues facing children in LMICs (eg, sanitation, potable water, household air pollution, and highly toxic pesticides). The Green Page contains 4 sections:

1. Demographics: Includes type of residential setting, school, work, and activities.

2. Exposure history: Includes parent occupations, overcrowding in home, pets, vectors of disease transmission, history of injuries (traffic, fire, chemical), venomous/poisonous animals, extreme temperatures.

3. Environmental exposure ratings (A/B/C): for various environmental conditions (air, water, soil/floor, sewage, waste, noise, chemicals, traffic) among the child’s environments including home, school, recreation, workplace, community.

4. Public services: Availability of basic services across the home, school, community; services include electricity, communication, waste collection/disposal, transportation, public lighting, health care centers, excreta treatment plant, sewage system, water supply.

Further, the WHO’s Pediatric Environmental Health Training Package provides specific guidance on the diagnosis and management of environmental health issues commonly encountered in LMICs.¹²⁷ 

To further assist pediatricians and pediatric trainees in making a diagnosis of environmental disease in children, a two-stage systematic approach to obtaining a history of environmental exposure is suggested.^128,129 In the first stage, pediatricians may wish to routinely ask a series of screening questions of every new patient, of every patient with a new disease, and of every patient with an exacerbation of disease. If positive responses are elicited to any of these screening questions, more detailed follow-up or referral to a Pediatric Environmental Health Specialty Unit (PEHSU), toxicologist, or another resource may be indicated (Table 4).

1. In the History of the Present Illness, consider any temporal relationship between onset of illness and exposures in the child’s environment. For example, did symptoms begin shortly after the child moved to a new school or day care center? Did they abate during vacation and then recrudesce after the child resumed school? Were symptoms temporally related to an event such as pesticide application, chemical spill, or air pollution episode? Were there similar symptoms or illness among other children in the same school or community?

2. In the Social and Family History, ask where the child attends school and what industrial facilities are near by the child’s home and school. Ask about the caregiver/parents’ employment, with particular attention to the possibility that a parent may inadvertently be bringing toxic materials home from work on their shoes or clothing (eg, pesticides, heavy metals, asbestos).

3. In the Review of Systems, routinely include this question: “Does the child now or previously have exposures to lead, fumes, chemicals, pesticides, dust, asbestos, loud noise, radiation, or other environmental hazards?”

Pediatricians in high-income countries are increasingly likely to care for foreign-born children and adolescents and have an important role in promoting these children’s health and wellness. The AAP has published resources to assist providers in the clinical care of immigrant children¹³⁰ and internationally adopted children.¹³¹ 

It is important for pediatric providers in the United States to be aware of the possibility that children and adolescents who have come to high-income countries from LMICs may have been exposed to toxic chemicals and other environmental hazards in their countries of origin. Such exposures might include lead from mining and smelting, arsenic from contaminated groundwater, mercury from artisanal gold mining, and pesticides from agriculture or extreme psychosocial stress. In addition, once arriving in the United States, immigrant children may face ongoing environmental exposures if they move into substandard housing, have parents who bring home work-related exposures (eg, pesticides in agricultural workers), or have family members who use toxic products imported from the home country (eg, Ayurvedic medicines, lead-containing cosmetics, or candies wrapped in lead foil). Appropriate histories might be difficult to obtain if the patient was adopted, and/or if there are language barriers. Using a qualified interpreter with every such encounter is key.

It is also important to assess the mental health of children who have emigrated from LMICs, because these children may have been exposed to poverty, complex sociopolitical circumstances, war, other forms of violence and famine, and may require referral for appropriate social services or mental health support.³ Mental health issues may be of particular concern in children who are refugees, and the CDC has developed guidance for mental health screening of refugee children.¹³² 

Recent decades have seen a dramatic rise in interest in environmental health among medical and public health professionals in the United States and across the globe. There have been small gains made in adding topics in environmental health, including climate change, into routine medical education. These educational programs are, however, not yet comprehensive, and they do not fully prepare physicians to address environmental concerns among their patients, especially patients in LMICs.^133–135 It is very important to include training in cultural humility and cultural competency in such education. Training in advocacy that provides pediatricians with the knowledge and tools they will need to be effective, science-based advocates for children’s environmental health is another important component of such training.

To fill this gap in medical education, organizations such as the AAP, the Academic Pediatric Association, and the WHO have launched initiatives to build capacity in pediatric environmental health. The Academic Pediatric Association has launched an environmental health fellowship that has trained more than 50 clinicians and scientists who have become leaders in the field^136,137 and has formed an Environmental Health Special Interest Group. The AAP Council on Environmental Health and Climate Change has convened pediatric environmental health champions (including trainees), raised the national profile of the field, and published the clinical handbook Pediatric Environmental Health (also known as the “Green Book”), now in its 4^th edition.⁶⁹ 

A national network of PEHSUs was established in 1998 by the US EPA and the Agency for Toxic Substances and Disease Registry (ATSDR). PEHSUs span the United States, and they provide consultation, guidance, and education for healthcare providers, public health agencies, and communities on key pediatric environmental health issues.^69,138,139 The WHO has launched an international network of Children’s Environmental Health Units, including the Unidades de Pediátrica Ambiental (UPAs) in Latin America, and created a comprehensive training program in pediatric environmental health. In addition to these valuable resources, additional online training materials, research journals, and clinical tools have been developed (Table 5).

Despite the great magnitude of their effects on human health, environmental hazards in LMICs have been neglected in the international development and global health agendas, as well as in the planning strategies of many countries. The foreign aid budgets of the European Commission, the US Agency for International Development, and bilateral development agencies allocate only minimal resources to the prevention control of ambient air pollution and chemical pollution.^140,141 No major foundation has made pollution control a priority. The data presented in Figure 1 illustrate the striking imbalance between pollution’s impacts on human health and the meager resources devoted towards its prevention and control (Figure 1).¹⁴² The investment by international development agencies in preventing a death caused by pollution is $14 versus $1250/death for malaria, $190/death for tuberculosis, and $165/death for HIV/AIDS.¹⁴³ 

Given the immense burden of disease attributable to modifiable environmental factors, increased financial support and capacity building in environmental health are urgently needed in all countries, and especially LMICs. Programs such as the WHO-National Institute of Environmental Health Sciences (NIEHS) Collaborating Centers and the Fogarty International Center (of the National Institutes of Health) offer international training programs, research, capacity building, and information sharing across countries, which have reduced disease burden around the world.^144,145 However, substantially more funding and investment in these type of programs are needed to fully address the complex and changing scope of environmentally related disease.

Environmental health training for medical personnel, public health professionals, and environmental technicians is critical for the development of locally tailored and sustainable environmental interventions. Primary prevention interventions in environmental health include strategies such as: implementing safely managed drinking water system, ending open defecation through installation of safe toilet facilities, increasing access to cleaner fuels and more efficient indoor cook stoves, and improving surveillance and control of chemical products.¹⁴⁶ 

These environmental interventions produce crosscutting health, social, and economic co-benefits, and support the vision of United Nation’s Sustainable Development Goals (SDGs). The 17 ambitious SDGs aim to eradicate global poverty by 2030 by focusing on sustainable strategies to ensure healthy environments for all, especially women and children.¹⁴⁷ As climate change accelerates and LMICs continue their trajectories on the epidemiological and environmental transitions, increased investment in research and infrastructure are needed to ensure a resilient future for all children and future generations.

Hazardous environmental exposures including air pollution, water pollution, and toxic chemical exposures have disproportionately great impacts on the health and development of children and adolescents in LMICs. Although advances have been made in improving environmental conditions for children in LMICs, their risk of environmentally related morbidity and mortality remains much higher than for children in high-income countries. To equip pediatricians to address these persistent problems, an increased emphasis on environmental health needs to be incorporated into medical education and into the clinical care of children and youth worldwide.

It is important that pediatric health care providers have knowledge of the environmental health exposures affecting the communities they serve in North America and in LMICs and that they are aware of the many resources available at the local national and international levels to address these hazards. Pediatricians and other child health experts can play key roles in protecting children’s health against environmental threats by routinely considering the possibility of environmental causation in the assessment of each child and through remaining ever alert to “sentinel events” that may signal the presence of a previously unrecognized environmental danger. Pediatricians can contribute additionally to protecting children against environmental hazards by participating in relevant policy and decision-making processes in their communities and by incorporating measures to protect children against environmental threats into primary care pediatrics and public health systems.

The already great need for pediatricians to be involved in protecting children against environmental threats to health will become still greater in the years ahead as climate change continues to cause direct and indirect impacts on the health and well-being of children around the world and to magnify the impacts on children’s health of other harmful exposures in the environment.

Lauren Zajac, MD, MPH, FAAP

Philip J. Landrigan, MD, MSc, FAAP

Lauren Zajac, MD, MHP, FAAP; Chairperson

Sophie J. Balk, MD, FAAP

Lori G. Byron, MD, FAAP

Gredia Maria Huerta-Montañez, MD, FAAP

Philip J. Landrigan, MD, FAAP

Steven M. Marcus, MD, FAAP

Abby L. Nerlinger, MD, FAAP

Lisa H. Patel, MD, FAAP

Rebecca Philipsborn, MD, FAAP

Alan D. Woolf, MD, MPH, FAAP

Kimberly A. Gray, PhD – National Institute of Environmental Health Sciences

Grace Robiou – US Environmental Protection Agency

Nathaniel G. DeNicola, MD, MSc – American College of Obstetricians and Gynecologists

CDR Matt Karwowski, MD, MPH, FAAP – Centers for Disease Control and Prevention National Center for Environmental Health and Agency for Toxic Substances and Disease Registry

Mary H. Ward, PhD – National Cancer Institute

Paul Spire

AAP

American Academy of Pediatrics

ASGM

artisanal and small-scale gold mining

CDC

Centers for Disease Control and Prevention

CO₂

carbon dioxide

LMICs

low- and middle-income countries

NCD

noncommunicable disease

PBDE

polybrominated diphenyl ether

PCBs

polychlorinated biphenyls

PEHSU

Pediatric Environmental Health Specialty Unit

PFAS

per- and polyfluoroalkyl substances

SDG

Sustainable Development Goals

WHO

World Health Organization