Environmental Protection

 Health is influenced by a wide range of environmental determinants, including air quality, water quality, sanitation, housing conditions, climate, biodiversity, and exposure to hazardous chemicals (WHO, 2024a). Preventive medicine seeks to minimise these environmental risks before they result in illness.

The World Health Organization estimates that approximately 24% of global deaths and 23% of all disability-adjusted life years (DALYs) are attributable to preventable environmental factors. Improvements in environmental conditions have been associated with reductions in cardiovascular diseases, respiratory illnesses, gastrointestinal infections, certain cancers, and mental health disorders (WHO, 2024a).

Environmental protection therefore represents primary prevention by eliminating or reducing health hazards at their source rather than treating diseases after they develop.

Climate change is recognised by the WHO as one of the greatest threats to global public health during the twenty-first century (WHO, 2024b). Rising global temperatures increase the frequency of heat-related illnesses, dehydration, cardiovascular complications, and mortality, particularly among older adults and individuals with chronic diseases.

Extreme weather events—including floods, droughts, wildfires, and storms—disrupt healthcare systems, damage infrastructure, reduce food production, and increase the risk of malnutrition and displacement. Climate change also alters the geographical distribution of disease vectors, contributing to the spread of malaria, dengue fever, Lyme disease, and other vector-borne diseases into previously unaffected regions (WHO, 2024b).

Air pollution remains one of the leading environmental causes of premature mortality worldwide. According to the World Health Organization, approximately 7 million premature deaths annually are associated with exposure to outdoor and household air pollution (WHO, 2024c).

Fine particulate matter (PM2.5), nitrogen dioxide, sulphur dioxide, and ground-level ozone increase the risk of coronary heart disease, stroke, chronic obstructive pulmonary disease (COPD), asthma, lung cancer, and adverse pregnancy outcomes (UNEP, 2024). Children, older adults, and individuals with pre-existing respiratory conditions are particularly vulnerable.

Reducing fossil fuel combustion, promoting renewable energy, and improving public transportation are among the most effective preventive strategies.

Access to clean water and adequate sanitation remains fundamental to disease prevention. Contaminated drinking water contributes to diarrhoeal diseases, cholera, typhoid fever, hepatitis A, and parasitic infections, particularly in low-resource settings (WHO, 2024a).

Industrial pollution, agricultural runoff containing pesticides and fertilisers, and inadequate wastewater treatment continue to threaten freshwater ecosystems and public health. Investment in water infrastructure and sanitation significantly reduces infectious disease transmission.

Healthy ecosystems provide numerous ecosystem services, including clean water, food production, pollination, climate regulation, and disease control (United Nations, 2024). Deforestation, habitat destruction, and biodiversity loss increase interactions between humans and wildlife, thereby 

increasing the likelihood of zoonotic disease emergence.

The COVID-19 pandemic highlighted the importance of maintaining ecosystem integrity to reduce future pandemic risks.

Several important trends are reshaping environmental protection as preventive medicine.

The One Health approach recognises the interconnected health of humans, animals, and ecosystems and promotes interdisciplinary collaboration among healthcare professionals, veterinarians, environmental scientists, and policymakers (WHO, 2024d).

The transition towards renewable energy sources - including solar, wind, and hydroelectric power - is reducing greenhouse gas emissions while simultaneously improving air quality and public health.

Nature-based solutions, such as wetland restoration, urban tree planting, coastal ecosystem protection, and reforestation, are increasingly adopted because they simultaneously enhance biodiversity, reduce climate risks, and improve community well-being.

Advances in environmental monitoring using satellite observations, remote sensing, artificial intelligence, and real-time air-quality sensors now enable earlier identification of environmental hazards and more effective public health responses.

Despite considerable progress, several environmental concerns continue to threaten preventive medicine.

Climate change is accelerating faster than adaptation efforts in many regions. Plastic pollution has resulted in widespread contamination of oceans, freshwater systems, soils, food products, and drinking water. Microplastics have been detected in human blood, lungs, and placental tissue, although their long-term health effects remain under investigation.

Chemical pollution also presents ongoing challenges because many industrial chemicals have not been fully evaluated for chronic health effects. Additionally, environmental injustice disproportionately affects lower-income populations, who often experience greater exposure to pollution and reduced access to healthy environments.

Several countries demonstrate that environmental protection can substantially improve public health.

The United Kingdom significantly improved air quality following the implementation of the Clean Air Acts, resulting in substantial reductions in respiratory illnesses and urban air pollution.

Costa Rica has successfully restored forest cover through conservation policies and payments for ecosystem services, while simultaneously promoting renewable electricity generation and biodiversity conservation.

Copenhagen, Denmark, has become an international model for sustainable urban transport, with extensive cycling infrastructure contributing to lower carbon emissions and improved population health.

Singapore has integrated green infrastructure into urban planning through extensive tree planting, water recycling systems, green buildings, and sustainable city design, improving both environmental quality and residents' well-being.

These examples demonstrate that environmental protection policies can generate measurable health, economic, and environmental benefits simultaneously.