The Global Centre for Risk and Innovation (GCRI)
Environmental hazards reach health through the air people breathe, the water they drink, the heat their bodies must shed and the chemicals that accumulate over years. Their effects are often diffuse, delayed and shared with other causes, which makes them easy to overlook and hard to attribute. This page sets out how environmental exposure becomes disease, how exposure and effect are measured, and what the evidence serves for health and environment authorities.
GCRI · Established · service level R0
Environmental health is the part of public health concerned with how air, water, heat, chemicals and the built environment affect people. Its effects are often diffuse, delayed and shared with other causes, so exposure is measured against WHO guidelines and attributed burdens are estimated with stated uncertainty.
How far each division sits from a large city, with the roads and airports that carry patients and supplies, shown for East Africa as an example geography for this subject.
The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.
Environmental health · Summer season · District 4
| People over 75 living alone | 1048 | 76 | Behind |
| Outdoor workers | 1932 | 45 | Behind |
| Care homes | 39 | 99 | On track |
Water, air, heat, pollution and health. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Ambient concentrations become personal exposure through where people live, work and spend their time, then dose through breathing rate, water intake and duration. Indoor sources such as household combustion of solid fuels can outweigh outdoor levels.
Heat raises risk for older people, outdoor workers, infants and people with chronic illness. Heatwaves increase hospital demand while reducing staff capacity and straining power for cooling, so bodies and services are stressed together.
Floods and failing sanitation spread faecal pathogens; drought concentrates contaminants and pushes people to unsafe sources. Arsenic, fluoride, nitrate and lead cause chronic harm that appears only after long exposure.
Heat raises ground-level ozone, wildfire smoke adds fine particles, and drought and dust compound both. Combined exposures act on the same organ systems, so effects estimated one hazard at a time can understate the joint burden.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Fine particulate matter | Airborne particles of 2.5 micrometres or less, known as PM2.5, which reach deep into the lungs and bloodstream. |
| WHO air quality guideline | A health-based concentration level for an air pollutant set by WHO, used as a reference for national standards. |
| Exposure-response function | The estimated relationship between the level of an exposure and the change in a health outcome. |
| Heat-health action plan | A plan that links heat forecasts to warnings and protective measures for people at risk. |
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Annual mean fine particulate matter | micrograms per cubic metre | annual | Ground monitors fused with satellite and model estimates | MODELLED |
| Population above the WHO air quality guideline | persons | annual | Exposure surfaces on gridded population | ESTIMATED |
| Heat stress | universal thermal climate index, degrees Celsius | daily | Reanalysis and weather forecasts | MODELLED |
| Heatwave exposure | person-days of heatwave exposure | seasonal | Temperature records on gridded population | ESTIMATED |
| Heat-related excess deaths | deaths above expected | seasonal | Vital registration against modelled baselines | ESTIMATED |
| Reliance on polluting cooking fuels | percent of population | annual | Household surveys, SDG indicator 7.1.2 | ESTIMATED |
| Drinking-water contaminant exceedance | percent of samples above the guideline value | monthly | Water quality surveillance | OBSERVED |
| Blood lead concentration | micrograms per decilitre | per survey | Biomonitoring surveys | OBSERVED |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| WHO Ambient Air Quality Database | Annual mean particulate matter and nitrogen dioxide from city monitors | Open, attribution, WHO terms of use |
| OpenAQ | Harmonised real-time and historical air quality measurements | Open; licence per contributing source |
| Copernicus Atmosphere Monitoring Service | Reanalysis and forecasts of aerosols, ozone and wildfire smoke | Free and open, attribution |
| ERA5 and ERA5-HEAT (Copernicus) | Temperature and thermal stress indices, the universal thermal climate index included | Free and open, attribution |
| WHO and UNICEF Joint Monitoring Programme | Drinking water, sanitation and hygiene service levels | Free and open, attribution |
| IHME Global Burden of Disease | Modelled burden attributable to environmental risk factors | Free for non-commercial use, attribution |
| Lancet Countdown on health and climate change | Indicators of heat exposure, health impacts and adaptation | Published report and data, terms per indicator |
Health Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Ministries of health and environment | Which pollutants and sources to regulate first, and which populations to protect | Exposure surfaces against guideline values; attributable burden with uncertainty |
| Municipal health and emergency authorities | When to activate heat-health action plans and where to open cooling centres | Heat stress forecasts with their skill; exposure of vulnerable groups by neighbourhood |
| Drinking-water regulators and suppliers | Which supplies need treatment, a source change or public advisories | Contaminant exceedance by supply; seasonal and flood-related contamination risk |
| Hospital systems | How to prepare staffing, cooling and admissions for heat and smoke episodes | Seasonal exposure outlooks; past admission patterns during episodes |
Environmental health connects a measured exposure to a health outcome.
Extreme heat strains the body's ability to regulate temperature and places stress on the heart, kidneys and lungs. Older people, infants, outdoor workers, people with chronic illness and those without cooling are most at risk, and much of the harm occurs on hot nights when the body cannot recover. Cities amplify heat through the urban heat island effect.
Fine particulate air pollution penetrates deep into the lungs and bloodstream and is associated with respiratory and cardiovascular disease. Floods spread contamination and disrupt treatment works; drought concentrates pollutants and reduces water for hygiene. Many exposures act together, and their combined effect can exceed the sum of their parts.
| Method or data | What it shows | Limits |
|---|---|---|
| Time-series and case-crossover studies | Short-term associations between exposure and outcomes | Confounding and exposure misclassification from fixed monitors |
| Cohort studies | Long-term effects of chronic exposure | Expensive, slow and dependent on follow-up quality |
| Exposure modelling with monitors and satellite data | Where and when people are exposed | Personal exposure differs from outdoor concentrations |
| Heat-health and air-quality early warning evaluation | Whether warnings change outcomes | Hard to separate warning effects from weather variation |
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.