What is Environmental Health?
Every time you drink a glass of water, breathe the air outside and inside your home, or eat food from your favorite restaurant, you're interacting with elements that impact your health. Environmental health is the field that connects these dots, such as tracking how our surroundings, from the obvious to the invisible, affect our wellbeing.
Beyond Clean Air and Water
When most people hear "environmental health," they think of pollution control or climate change. While these are important components, the field encompasses more. Environmental health examines how our surroundings, both natural and built, impact human health and quality of life.
According to the World Health Organization, each year, approximately 12.6 million deaths globally are due to unhealthy environments. That's nearly one in four deaths worldwide linked directly to the environments we create and inhabit. In the Philippines, where rapid urbanization meets climate change challenges, these numbers present an urgency that we cannot ignore.
Climate Change: A Defining Health Challenge
In the World Risk Report 2025 released September 24, 2025, The Philippines, once again, is ranked first as the most disaster-prone country in the world, underscoring its extreme vulnerability to climate-driven hazards like storms, floods, and earthquakes.
Climate change intensifies existing environmental health concerns while creating entirely new ones. In Southeast Asia, rising temperatures have changed the behaviors and habitat of disease vectors such as mosquitoes, leading to increased dengue transmission. In the Philippines, we have observed dengue outbreaks even outside the usual rainy season, with cases increasing to 73% in the first months of 2025 compared to the previous year, before the expected dengue season.
The Invisible Threats in Daily Life
Every day, we face invisible environmental hazards. Endocrine-disrupting chemicals (EDCs), interfere with hormone systems through water supplies, food containers, cosmetics, and household items. These include bisphenols in plastics, phthalates in toys, and agricultural pesticides that mimic or block natural hormones. Pregnancy exposure links to altered brain development and disease susceptibility that may not manifest for decades.
Indoor air pollution from cooking, heating, and cleaning products can exceed outdoor pollution levels. According to WHO, it causes 3.2 million premature deaths annually, including 237,000 children under five. In the Philippines, where traditional cooking methods remain common, this means increased respiratory infections, cardiovascular disease, and childhood pneumonia among vulnerable populations.
Microplastics now contaminate human fluids and food chains globally. In the Philippines, it is worsened with our "sachet economy" and with 35% of all plastic waste ending up directly in the environment. Filipino researchers found 97% of sampled milkfish (bangus) contained microplastics. These particles can transport harmful chemicals into our bodies while potentially releasing EDCs as they degrade.
The Inequity Gap
Environmental health threats don't affect all communities equally. In the Philippines, 3.7 million Filipino families in informal settlements face disproportionate exposure to environmental hazards, half a million live in slums and high-risk areas. Poor ventilation and overcrowding increase disease transmission, while residents endure compound exposures: industrial emissions, occupational hazards from informal work, contaminated water, and inadequate sanitation. During increasingly severe typhoons and floods, these communities suffer first and worst from disrupted health services.
The Role of Environmental Health Science
“genetic background loads the gun, but environment pulls the trigger”
Dr. Bray, in his study on obesity, noted that genes create a potential for a disease, but environmental factors trigger it to manifest.
This is where environmental health science becomes vital. It bridges public health and environmental science, translating complex data into action - setting safe water standards, assessing health impacts of new facilities, and investigating environmental triggers to unusual disease patterns. For the Philippines, building local environmental health capacity is our best chance to prevent illness and death, especially in vulnerable communities.
Moving Forward
Addressing modern environmental health challenges may seem daunting, but there are steps we can take to create incremental change, and some positive momentum is already building in the Philippines.
Building Environmental Health Literacy and Ensuring Community Participation When communities understand environment-health links, they become powerful advocates for change. Those living with environmental hazards must have meaningful roles in decisions. Their lived experiences provide insights that offices and labs might miss. They're not just beneficiaries but partners in crafting solutions. This means integrating environmental health into schools, community programs, and public campaigns. Teaching families practical knowledge: why ventilation matters when cooking, which plastics to avoid, how to spot neighborhood hazards. An informed citizenry doesn't just protect itself, it demands better from industries and government.
Strengthening Governance and Policy Environmental health considerations must be woven into all development planning. We need strengthened environmental health units with clear mandates and adequate resources. Local offices must activate their Environmental Health Councils, moving them from paper entities to active bodies. Existing policies need reassessment because times change, standards update, new threats emerge.
Prevention Over Reaction Too often, we wait for outbreaks or disasters before acting. Research institutions should investigate emerging threats for potential health impacts, with findings guiding policy and precautionary measures. This is critical for protecting vulnerable populations against contaminants that cause diseases manifesting in later life stages.
Environmental health protects the communities and ecosystems we depend on, especially those living closest to nature who often face the greatest risks.
Why This Matters Now
Environmental health is invisible until it isn't - until cancer clusters emerge, the baby is born with defects, children struggle to breathe, or entire communities fall ill. The challenge is that prevention must happen now to prevent diseases that won't manifest for years. This makes it difficult to prioritize for decision-makers and funders.
Yet evidence shows that robust environmental health systems reduce respiratory and waterborne diseases, support childhood development, and lower cancer risks. Investing in these systems isn't just about disease prevention: it's about securing sustainable growth that safeguards both public health and economic opportunity.
Environmental health protects the communities and ecosystems we depend on, especially those living closest to nature who often face the greatest risks.
The time to act is now, before the invisible becomes irreversible.
Dr. Hazel Fajardo is an environmental health specialist with field experience as a rural health physician in the Philippines.
All photos by the author, taken during deployment as a rural health physician in the Bicol Region, Philippines, 2017-2019
