Environmental health: Nearly one in four deaths worldwide are linked to unhealthy environments
Environmental health: 13.7 million deaths yearly—1 in 4 linked to our surroundings
Eight-year-old Aisha woke up struggling to breathe.
Her mother, Mariam, heard the familiar wheeze from across their small apartment in Delhi. Aisha’s asthma had worsened since they’d moved here three years ago—the same year construction started on the highway just 50 meters from their window. Now truck exhaust, construction dust, and industrial emissions from nearby factories created a permanent haze that burned Mariam’s eyes when she hung laundry.
Last month, Aisha missed a week of school during a pollution spike when the air quality index exceeded 400—”hazardous” by any standard. Her inhaler barely helped. The clinic doctor said her lungs showed damage consistent with years of smoke exposure, though she’d never been near a cigarette.
“I grew up in a village with clean air,” Mariam said, tears welling as she watched her daughter struggle. “I came to the city for a better life, better opportunities for my children. Instead, my daughter can’t breathe. The environment here is making her sick.”
Aisha’s story represents a global crisis: according to WHO’s work on environmental health, in 2016, 13.7 million deaths—representing 24% of global fatalities—were attributed to modifiable environmental risks.
Nearly one in four deaths worldwide are linked to environmental conditions we could change. And the ongoing environmental crisis is profoundly affecting health as climate change intensifies, biodiversity declines, and pollution becomes ubiquitous.
What Is Environmental Health?
Environmental health encompasses all aspects of how our surroundings affect our health. Good health depends on clean air, a stable climate, a preserved natural environment, as well as access to adequate water, sanitation and hygiene. It also requires protection from harmful radiation, unsafe chemical management, and unhealthy working conditions.
The scope is enormous: the air we breathe, the water we drink, the food we eat, the chemicals we’re exposed to, the climate we live in, the workplaces where we spend our days, the cities where we live, and the natural ecosystems we depend on.
A healthy environment could prevent nearly a quarter of the global disease burden—that’s millions of deaths and even more cases of disease and disability that could be prevented through environmental improvements.
Dr. Sofia Martinez, an environmental epidemiologist who has studied health impacts across multiple continents, explained the fundamental importance: “Every breath you take, every sip of water, every meal you eat, every surface you touch—your environment is constantly interacting with your body. When those environmental factors are healthy, your body thrives. When they’re polluted, toxic, or unstable, your health suffers. It’s that simple and that profound.”
For more on how our surroundings shape health, see our article on the social and environmental determinants of health.
The Staggering Disease Burden
Almost all diseases are influenced by unhealthy environments. Noncommunicable diseases (NCDs)—including heart disease, chronic respiratory diseases, and cancers—are the most affected.
Air pollution alone is responsible for millions of deaths each year. People breathe polluted air and develop heart disease, stroke, lung cancer, and chronic obstructive pulmonary disease (COPD). Children develop asthma. Pregnant women exposed to pollution have babies with lower birth weights and developmental problems.
Infectious diseases are also significantly impacted. Pathogens are transmitted through unsafe water, inadequate sanitation, and poor hygiene practices. Mosquitoes and other disease vectors thrive in conditions created by environmental degradation and climate change. Zoonoses—diseases jumping from animals to humans—are rising due to ecosystem disruption, deforestation, and wildlife trade.
Additionally, antimicrobial resistance poses a growing threat, especially when wastewater and solid waste are not properly managed. Antibiotics and resistant bacteria flow into water systems, spreading resistance throughout communities and ecosystems.
According to WHO data on public health and environment, the health impacts of poor environmental conditions occur not only directly but also indirectly, through effects on food production, migration, economic instability, and social inequalities.
WHO’s question and answer on estimating attributable disease burden explains how researchers calculate what portion of disease is caused by environmental factors.
Climate Change: Amplifying Every Threat
Climate change is exacerbating health risks by increasing the frequency and severity of extreme weather events, including deadly heatwaves. WHO published a fact sheet on heat and health documenting how rising temperatures are killing thousands during heat events.
The shifting distribution of climate-sensitive disease vectors is creating new patterns of infectious diseases. Mosquitoes carrying dengue, malaria, and other diseases are moving to areas where they’ve never been before as temperatures warm.
Climate change also affects food production—droughts reduce crop yields, floods destroy harvests, changing rainfall patterns disrupt agriculture. Food insecurity drives migration as people flee areas that can no longer sustain them, creating humanitarian crises and health emergencies.
WHO and Brazil issued a November 2025 call to urge swift action on the Belém Health Action Plan at COP30, highlighting the urgency of addressing climate and health connections.
The WHO-WMO Joint Climate and Health Programme brings together meteorological and health expertise to address these challenges.
Urban Environments: Where Most People Live
In October 2025, WHO called for a new era of strategic urban health action with a global guide to unlock healthy, prosperous, and resilient societies.
More than half the world’s population now lives in cities. Urban environments concentrate environmental health challenges—air pollution from traffic and industry, inadequate green spaces, heat islands from concrete and asphalt, noise pollution, poor housing conditions, and limited access to clean water and sanitation in informal settlements.
But cities also offer opportunities for solutions: efficient public transportation reducing pollution, green infrastructure providing cooling and air filtration, compact development reducing energy use, and concentration of resources enabling better services.
WHO’s work on urban health addresses these challenges and opportunities.
The Hidden Dangers: Chemicals and Waste
Modern life exposes us to thousands of chemicals, many never tested for long-term health effects. Lead poisoning, mercury exposure, pesticide contamination, industrial chemicals in consumer products, and pharmaceutical pollution in water all contribute to disease burden.
WHO highlighted in December 2025 the health risks and opportunities in the global waste crisis, emphasizing how improper waste management creates health hazards while proper waste management offers health benefits.
Electronic waste (e-waste) is a growing concern. WHO’s fact sheet on e-waste details how discarded electronics release toxic substances including lead, mercury, and cadmium that contaminate soil and water.
WHO’s work on chemical safety and radiation addresses these largely invisible threats. In December 2025, global experts convened in Vienna to discuss radiation protection in medicine.
Workplace Hazards
Unsafe working conditions contribute to risks across all major disease categories. Occupational exposures to dust, chemicals, noise, vibration, extreme temperatures, and dangerous equipment cause injuries, respiratory diseases, cancers, hearing loss, musculoskeletal disorders, and heat stress.
WHO’s Initiative against extreme heat and health risks in workplaces and major events addresses growing concerns about worker safety in a warming world.
The occupational health work at WHO emphasizes prevention and creating safe, healthy workplaces.
WHO’s Response: Leadership and Action
WHO’s Environment, Climate Change and Health department coordinates global efforts through several key strategies:
Providing leadership on transitions: WHO guides critical transitions in energy and transportation essential for mitigating environmental health risks, and works to stimulate good governance practices that integrate health and environmental considerations across relevant sectors.
Promoting knowledge generation and dissemination: WHO facilitates generation and sharing of evidence-based knowledge, establishing norms and guidelines that drive effective solutions. WHO steers research, monitors health risks, and assesses effectiveness of implemented solutions.
Supporting capacity building and scaling action: WHO assists countries in strengthening their ability to address environmental health challenges by building local capacity and supporting scalable mechanisms for action. By fostering cross-sectoral collaboration, WHO helps countries implement healthy and sustainable policies and programs.
Building emergency preparedness: WHO strengthens emergency preparedness and response systems for environment-related incidents such as natural disasters, pollution events, and outbreaks of diseases linked to environmental changes.
The Technical Advisory Group on Economics for Environment, Climate Change and Health provides expertise on economic aspects of environmental health interventions.
Solutions Exist—We Must Act
Effective solutions exist to prevent disease and mitigate potential burden on health systems. These solutions could significantly reduce associated costs, which are increasingly pressing in many countries.
Urgent action is needed to transform how we live, work, produce, consume, and govern. Strengthening primary prevention is essential, given the substantial reduction in disease burden it can offer, as well as potential savings in healthcare costs and resources.
Cross-sectoral collaboration is crucial in addressing environmental determinants of health, including the health, energy, industry, agriculture, and transport sectors. Resolution WHA72.15 on health environment and climate change provides global policy framework.
Integrating actions across sectors often leads to significant co-benefits and cost reductions. For example, shifting to clean energy reduces air pollution (preventing respiratory and cardiovascular disease), mitigates climate change, creates jobs, and improves energy security—multiple benefits from one transition.
Mariam, watching her daughter Aisha use her inhaler again, dreams of change. “I want my daughter to run and play without gasping for air. I want her to go to school every day, not miss weeks because pollution makes her sick. I want a future where the environment helps children thrive instead of making them ill.”
With 13.7 million deaths annually—24% of all global deaths—linked to modifiable environmental risks, the environmental health crisis demands transformation. The solutions exist. The science is clear. The question is whether we’ll act with the urgency this crisis demands.
Frequently Asked Questions (FAQs)
Environmental health encompasses all aspects of how our surroundings affect our health. Good health depends on clean air, a stable climate, a preserved natural environment, access to adequate water, sanitation and hygiene, protection from harmful radiation, unsafe chemical management, and unhealthy working conditions. A healthy environment could prevent nearly a quarter of the global disease burden. In 2016, 13.7 million deaths—representing 24% of global fatalities—were attributed to modifiable environmental risks, meaning nearly one in four global deaths are linked to environmental conditions we could change. The ongoing environmental crisis is profoundly affecting health as climate change intensifies, biodiversity declines, and pollution becomes ubiquitous. Health impacts of poor environmental conditions occur not only directly but also indirectly through effects on food production, migration, economic instability, and social inequalities. WHO’s Environment, Climate Change and Health department coordinates global efforts. WHO provides data on public health and environment and guidance on estimating attributable disease burden.
Almost all diseases are influenced by unhealthy environments. Noncommunicable diseases (NCDs)—including heart disease, chronic respiratory diseases, and cancers—are most affected. Air pollution alone is responsible for millions of deaths each year from heart disease, stroke, lung cancer, and chronic obstructive pulmonary disease (COPD). Children develop asthma from pollution exposure. Infectious diseases are significantly impacted—pathogens transmitted through unsafe water, inadequate sanitation, and poor hygiene; mosquitoes and disease vectors thrive in conditions created by environmental degradation and climate change; zoonoses (diseases jumping from animals to humans) rise due to ecosystem disruption, deforestation, and wildlife trade. Antimicrobial resistance poses growing threat especially when wastewater and solid waste are not properly managed. Climate change exacerbates health risks by increasing frequency and severity of extreme weather events including deadly heatwaves (WHO fact sheet on heat and health). Unsafe working conditions contribute to risks across all major disease categories. Chemical exposures from lead, mercury, pesticides, and e-waste (WHO fact sheet) cause additional health problems. WHO tracks data on ambient air pollution, household air pollution, and water, sanitation and health.
Climate change is exacerbating health risks by increasing frequency and severity of extreme weather events including deadly heatwaves. The shifting distribution of climate-sensitive disease vectors is creating new patterns of infectious diseases—mosquitoes carrying dengue, malaria, and other diseases moving to areas where they’ve never been before as temperatures warm. Climate change affects food production through droughts reducing crop yields, floods destroying harvests, and changing rainfall patterns disrupting agriculture. Food insecurity drives migration as people flee areas that can no longer sustain them, creating humanitarian crises and health emergencies. WHO and Brazil urged swift action on the Belém Health Action Plan at COP30 in November 2025. The WHO-WMO Joint Climate and Health Programme brings together meteorological and health expertise. WHO’s Initiative against extreme heat and health risks in workplaces and major events addresses growing worker safety concerns. Resolution WHA72.15 on health environment and climate change provides policy framework. WHO also works on climate change health topics and sustainable development.
WHO’s efforts to advance the global agenda for creating healthier environments include: providing leadership on key transitions by guiding critical transitions in energy and transportation essential for mitigating environmental health risks and stimulating good governance practices that integrate health and environmental considerations across relevant sectors; promoting knowledge generation and dissemination by facilitating generation and sharing of evidence-based knowledge, establishing norms and guidelines that drive effective solutions, steering research, monitoring health risks, and assessing effectiveness of implemented solutions; supporting capacity building and scaling action by assisting countries in strengthening their ability to address environmental health challenges, building local capacity, and supporting scalable mechanisms for action; and building emergency preparedness and response systems for environment-related incidents such as natural disasters, pollution events, and outbreaks. WHO called for new era of strategic urban health action in October 2025 and highlighted health risks and opportunities in global waste crisis in December 2025. The Technical Advisory Group on Economics for Environment, Climate Change and Health provides expertise.
Effective solutions exist to prevent disease and mitigate potential burden on health systems, significantly reducing associated costs which are increasingly pressing in many countries. Urgent action is needed to transform how we live, work, produce, consume, and govern. Strengthening primary prevention is essential given substantial reduction in disease burden it can offer and potential savings in healthcare costs and resources. Cross-sectoral collaboration is crucial in addressing environmental determinants of health including the health, energy, industry, agriculture, and transport sectors. Integrating actions across sectors often leads to significant co-benefits and cost reductions—for example, shifting to clean energy reduces air pollution (preventing respiratory and cardiovascular disease), mitigates climate change, creates jobs, and improves energy security. Specific solutions include improving air quality through pollution controls, ensuring access to safe water and sanitation, proper chemical and waste management, creating green urban spaces, transitioning to clean energy, protecting workers from occupational hazards, and building climate-resilient health systems. WHO works on air pollution, chemical safety, children’s environmental health, occupational health, radiation safety, ultraviolet radiation, urban health, water, sanitation and hygiene, and health impact assessment.
- WHO Environmental Health Topic
- WHO Environment, Climate Change and Health Department
- WHO Fact Sheet: Heat and Health
- WHO Fact Sheet: Electronic Waste (e-waste)
- WHO Q&A: Estimating Attributable Disease Burden
- Public Health and Environment Data
- Ambient Air Pollution Data
Disclaimer: This article is an adaptation of publicly available information from WHO’s Environmental health topic page (WHO, Geneva. Licence: CC BYNC-SA 3.0 IGO). WHO is not responsible for the
content or accuracy of this adaptation. This content is for informational and educational purposes
only and does not constitute medical advice. ObserverVoice.com is a news and information platform
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