The air you breathe, the water you drink, and the places you live are more than just your surroundings—they are a part of you.
We often think of our health as being determined by genetics and lifestyle choices. Yet, a third, equally critical factor surrounds us from moment one: our environment. Environmental health is the field of science that studies how the environment influences human health and disease 5 . It is the discipline that connects the air we breathe, the water we drink, and the communities we live in to the state of our physical well-being. In an era of increasing climate concerns, understanding these connections is not just academic—it is essential for our future.
This article explores how scientists are working to unravel the complex interactions between our surroundings and our health, aiming to build a safer, healthier world for all.
Indoor and outdoor air pollution affects respiratory and cardiovascular health.
Contaminated water sources can spread disease and expose populations to toxins.
Urban planning, housing, and community design impact physical and mental health.
Our environment is a constant, silent partner in our lives. To understand its influence, we must first grasp a few core concepts that form the bedrock of environmental health science.
The National Institute of Environmental Health Sciences (NIEHS) defines its mission as researching "how the environment affects biological systems across the lifespan" with the goal of reducing disease and promoting human health 1 . This research isn't limited to external pollutants; it also includes internal factors like diet, metabolism, and stress, and it considers all stages of life 1 .
To navigate this complex field, scientists rely on several key ideas:
This is the total amount of an environmental hazard that comes into direct contact with your body. Exposure has three parts: the source of the hazard, its pathway through the environment, and the point of contact with you 5 .
Key ConceptUnlike exposure, the dose is the specific amount of a hazard that actually enters your body. It depends on the duration and frequency of exposure, as well as individual characteristics like body size 5 .
Key ConceptNot everyone is affected by an environmental hazard in the same way. Factors such as age (including fetal development in pregnant women), pre-existing health conditions, and the efficiency of one's immune system can make some individuals more vulnerable than others 5 .
Key ConceptThis principle asserts that everyone has a right to live in a healthy environment, regardless of their race, culture, or income. It seeks to address the fact that the burdens of environmental pollution are often disproportionately borne by minority and low-income communities 5 .
Social DimensionEnvironmental factors can impact our health through a variety of channels. These hazards are often categorized to help scientists and public health officials study and mitigate them 5 :
Living organisms, or their products, that can cause disease. Examples include bacteria, viruses, and insects.
Result from mismanagement or exposure to chemicals, such as pesticides, lead, and industrial pollutants.
Factors like radiation from radon gas or ultraviolet light that can directly harm the body.
These include stress, depression, and anxiety triggered by environmental factors like noise, overcrowding, or social conflict.
Data visualization showing the percentage of global disease burden attributable to environmental factors. Source: World Health Organization estimates.
As climate change leads to more frequent and intense wildfires, a critical question has emerged: How does wildfire smoke traveling thousands of miles affect the health of people living far from the flames? A compelling experiment, prompted by real-world events, sought to answer this.
In June 2023, smoke from massive Canadian wildfires drifted across the United States, creating hazy skies and poor air quality even on the East Coast. Researchers saw a natural opportunity to investigate the health effects of this widespread exposure 2 .
This type of study relies on a combination of environmental monitoring and public health data analysis. The procedure can be broken down into several key steps:
The findings were striking. The study revealed a 20% increase in medical visits for lung and heart conditions in Maryland during the six "hotspot" days of intense wildfire smoke in June 2023 2 .
| Condition Category | Examples of Specific Conditions | Notes on Increased Vulnerability |
|---|---|---|
| Lung Conditions | Asthma, COPD, bronchitis | Particles in smoke can penetrate deep into the lungs, causing inflammation and difficulty breathing. |
| Heart Conditions | Heart attacks, arrhythmias, stroke | Tiny particles can enter the bloodstream, inflaming blood vessels and increasing clotting risks. |
| General Vulnerability | Children, the elderly, those with pre-existing conditions | These groups often have less resilient respiratory and cardiovascular systems 8 . |
| Pollutant | Description | Primary Health Concern |
|---|---|---|
| Particulate Matter (PM2.5) | Microscopic solid or liquid particles smaller than 2.5 micrometers in diameter. | Can be inhaled deep into lung tissue and even enter the bloodstream, affecting both respiratory and cardiovascular systems. |
| Carbon Monoxide (CO) | A colorless, odorless gas formed by incomplete combustion. | Reduces oxygen delivery to the body's organs and tissues. |
| Volatile Organic Compounds (VOCs) | A large group of chemicals that easily become vapors or gases. | Can cause eye, nose, and throat irritation; headaches; and some are known carcinogens. |
| Polycyclic Aromatic Hydrocarbons (PAHs) | A class of chemicals commonly formed during the burning of organic matter. | Many are known to be mutagenic and carcinogenic with long-term exposure. |
Comparison of hospital visits during normal days vs. wildfire smoke days.
This experiment was crucial because it provided concrete evidence of a direct public health threat. It demonstrated that the danger of wildfires is not confined to the immediate vicinity of the fire but can have continent-scale consequences.
To conduct research like the wildfire smoke study, scientists depend on a sophisticated array of tools and methods. These technologies allow them to detect minute quantities of pollutants, analyze complex mixtures, and understand how chemicals move and change in the environment.
| Tool or Reagent | Function | Example Use Case |
|---|---|---|
| Mass Spectrometry | Detects and identifies unknown chemicals and measures known ones at very low concentrations in water, soil, and air 9 . | Identifying specific toxic chemicals from an industrial spill in a river. |
| Discrete Analyzers | Automated instruments that use ready-to-use reagents to test for multiple chemicals in water samples quickly and accurately 4 . | High-volume testing of nitrate and phosphate levels in wastewater to monitor pollution. |
| Ready-to-Use Test Reagents | Pre-mixed chemical kits for analyzing specific water quality parameters like ammonia, chloride, and phosphate, saving time and reducing error 4 . | Rapid, standardized testing of drinking water for heavy metals like hexavalent chromium. |
| Air Quality Monitors | Devices that measure the concentration of pollutants like PM2.5, ozone, and CO in the air in real-time. | Providing the public with air quality indexes (AQI) during a smog event or wildfire 8 . |
| Biomarkers | An objective measure (e.g., in blood or urine) of what is happening in the body at a given moment due to an environmental exposure 1 . | Measuring lead levels in children's blood to assess exposure from old paint or contaminated soil. |
Precise chemical identification and quantification
Standardized chemical analysis
Real-time pollution tracking
Biological exposure assessment
Environmental health science reveals a fundamental truth: our well-being is inextricably linked to the health of our planet. From the global challenge of climate change to the local concern of lead in drinking water, our environment plays a decisive role in shaping our health. The field is not just about identifying problems; it is about creating solutions through innovative science, leveling the playing field through environmental justice, and empowering communities to take action.
As the NIEHS states, "As we learn more about how factors in the environment affect health, we enhance our ability to create a healthier environment and prevent disease and disability" 1 .
This knowledge empowers us all—from policymakers and scientists to community advocates and individuals—to contribute to a healthier, more sustainable world for generations to come.
Developing technologies and policies for a healthier environment
Ensuring equitable protection from environmental hazards
Empowering communities to address local environmental concerns