Courses in development extend the scope to further subjects: Global health security governance; Climate-sensitive health risk.
02Maps
Build a twin of any place
Search any place or open the world; the layers and generators follow public health emergencies and epidemics on the planet map, the globe and in 3D.
Health and SocietyAny placeTwin builder
Delhi and its National Capital Territory core, India. Flat plan of the same data: relief as contours from the inline grid, the WorldPop count grid as cells, the mapped hospitals and the numbers below. The 3D twin opens on devices that can draw it, once its data and code have been checked.
Terrain 191 to 315 m
950 hospitals
26,073,018 people in the box, 2020
Population density, GPW v4.11 (2020): read live when the 3D twin opens
Air quality, Copernicus CAMS via Open-Meteo (hourly, 5 days): read live when the 3D twin opens
Nitrogen dioxide column, TROPOMI (Sentinel-5P): read live when the 3D twin opens
Surface air temperature, AIRS (daily, day): read live when the 3D twin opens
Urban heat island, summer daytime 2013: read live when the 3D twin opens
Built-up and settlement extent, HBASE 2010: read live when the 3D twin opens
Credits and dates per layer are listed under the stage. Relief in the twin is exaggerated ×1.5 for legibility.
Drag to move, right drag or Shift with a drag to turn and tilt, Ctrl with the wheel to zoom. Keyboard: arrows move, Shift with arrows turn and tilt, + and – zoom, 0 resets, V steps through the views, Escape clears.
People per cell, WorldPop 2020 People per cell in 2020, summed from the national 1 km raster onto a 100 by 90 grid of about 490 by 550 metres, drawn as columns with a quantile legend; click a cell to read it. WorldPop (www.worldpop.org), University of Southampton, 2020 UN-adjusted 1 km, CC BY 4.0; summed per cell. read 2026-10-17.Estimate: A modelled 2020 estimate adjusted to UN totals; never a count of people affected; cells outside the national file are empty.
Population density, GPW v4.11 (2020) People per square kilometre in 2020, draped on the terrain as context for the count columns. Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0. Live: this page requests gibs.earthdata.nasa.gov when the layer is opened; the data date is printed with it.We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).Estimate: Exposure context only; a 2020 estimate, never a count of people affected; a static product, the year 2020 is printed.
Air quality, Copernicus CAMS via Open-Meteo (hourly, 5 days) Hourly PM2.5, PM10, nitrogen dioxide and ozone from the CAMS global model at the clicked point, five days from the request; the first chart opens at Connaught Place. Weather data by Open-Meteo.com (CC BY 4.0); air quality: Copernicus Atmosphere Monitoring Service (CAMS). Live: this page requests air-quality-api.open-meteo.com when the layer is opened; the data date is printed with it.Estimate: Model output at about 40 km resolution, not monitor readings; never a warning; the reference line is the WHO 2021 guideline, not a local standard.
Nitrogen dioxide column, TROPOMI (Sentinel-5P) Tropospheric nitrogen dioxide column for the day shown, draped on the terrain. TROPOMI tropospheric nitrogen dioxide column, ESA Copernicus Sentinel-5P (contains modified Copernicus Sentinel data), via NASA GIBS, with the product date. Live: this page requests gibs.earthdata.nasa.gov when the layer is opened; the data date is printed with it.We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).Estimate: A column amount, never a ground-level concentration or a health warning.
Surface air temperature, AIRS (daily, day) Daytime surface air temperature for the day shown, the heat layer of the twin. AIRS L3 surface air temperature (day), NASA, via NASA GIBS, with the product date. Live: this page requests gibs.earthdata.nasa.gov when the layer is opened; the data date is printed with it.We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).Estimate: A satellite retrieval at about 1 degree; not a station reading and not a heat warning.
Urban heat island, summer daytime 2013 The 2013 urban minus rural summer daytime surface temperature difference. CIESIN, Columbia University, and NASA SEDAC: Global Urban Heat Island (UHI) Data Set, 2013. Live: this page requests gibs.earthdata.nasa.gov when the layer is opened; the data date is printed with it.We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).Estimate: A 2013 static product; the city has grown since; the year is printed.
Built-up and settlement extent, HBASE 2010 Built-up extent in 2010 from Landsat, draped on the terrain. CIESIN, Columbia University, and NASA SEDAC: Global Human Built-up And Settlement Extent (HBASE) 2010. Live: this page requests gibs.earthdata.nasa.gov when the layer is opened; the data date is printed with it.We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).Estimate: A 2010 classification; the year is printed.
Why this place: One box of about 49 by 50 kilometres holds the densest part of a metropolitan region of more than thirty million people, with winter air pollution among the highest measured in any city, extreme pre-monsoon heat, a mapped hospital network and a strong urban heat island, so exposure, environmental health and health-system capacity can be taught where the signals are largest. Data quality: WorldPop and GPW v4 give the count and density, HBASE the built-up extent, the Copernicus CAMS air-quality forecast through Open-Meteo answered 178.8 micrograms per cubic metre of PM2.5 for the first hour of 17 October 2026, TROPOMI nitrogen dioxide and AIRS surface air temperature are daily via GIBS, and OpenStreetMap maps the hospitals. It connects to the Pollution and environmental health, Public health emergencies and epidemics, Health systems and health care resilience, Human development, poverty and inequality and Work, skills and occupational safety disciplines of the atlas.
Flat plan of the same data: relief as contours from the inline grid, the WorldPop count grid as cells, the mapped hospitals and the numbers below. The 3D twin opens on devices that can draw it, once its data and code have been checked.
The boundaries, names and designations shown do not imply any judgement on the legal status of any territory, or any endorsement or acceptance of such boundaries. Countries: Natural Earth (public domain).
03Live map
Environmental exposure in India
Haze, nitrogen dioxide, dust, surface heat by day and night, and where people live, over India.
The interactive map needs JavaScript; the layer list and sources are below.
Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.
Environmental exposure, framed on India.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.
We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
MODIS and VIIRS atmosphere products, NASA LANCE and LAADS DAAC; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
OMI nitrogen dioxide (Aura) and OMPS aerosol index (Suomi NPP), NASA; distributed by the NASA GES DISC; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
MERRA-2 reanalysis, NASA Global Modeling and Assimilation Office; distributed by the NASA GES DISC; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). doi:10.7927/H49C6VHW. CC BY 4.0
NASA Fire Information for Resource Management System (FIRMS), VIIRS 375 m active fire product, NASA LANCE; vector tiles via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
NASA GIBS: We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).
Air quality forecast, 5 days, PM2.5 (CAMS via Open-Meteo): Contains modified Copernicus Atmosphere Monitoring Service information 2026.
Past year, daily temperature (ERA5 via Open-Meteo): Contains modified Copernicus Climate Change Service information 2026.
Weather data by Open-Meteo.com (https://open-meteo.com/), licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
Optional layers (12 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.
Layers and dates
Aerosol optical depth, daily: VIIRS NOAA-20 Deep Blue AOD, NASA LANCE · 13 Oct 2026
Land surface temperature, day, 8-day composite: VIIRS NOAA-20 Level 3, 8-day, NASA LANCE · 14 Sep 2026
Nitrogen dioxide, lower atmosphere column: OMI Aura, NASA GES DISC · 10 Oct 2026
Surface dust PM2.5, monthly mean: MERRA-2, NASA GMAO / GES DISC · July 2026
Land surface temperature, night, 8-day composite: VIIRS NOAA-20 Level 3, 8-day, NASA LANCE · 14 Sep 2026
Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
Active fires and thermal anomalies: VIIRS NOAA-20 375 m (FIRMS), NASA LANCE FIRMS · 13 Oct 2026
Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
04The subject
The subject, methods and measures and debates and bodies
The field and its scope
For emergency planners, field epidemiologists and public health officers who must detect an outbreak early, assess it under the International Health Regulations and explain the risk while the evidence is still thin.
Quantities and units
Methods and their limits
Each method is listed with what it assumes and where it fails.
What the field debates
Bodies that set practice, and the data they publish
Bodies and standards are named so learners can find and apply their published work; the Academy teaches their use and links to the publisher, and no affiliation is implied.
05The method
From the first case to the notification: how the days to detection set the size of the job
Every day an outbreak grows undetected multiplies the cases that exist when it is found, the contacts that have to be traced and the tracing coverage needed to bring the effective reproduction number below one; time to detection is the quantity that response capacity is bought against.
Sources: Fraser, Riley, Anderson and Ferguson, Factors that make an infectious disease outbreak controllable (2004); Kucharski and others, Early dynamics of transmission and control of COVID-19: a mathematical modelling study (2020); Heymann and others, Global health security: the wider lessons from the west African Ebola virus disease epidemic (2015); World Health Organization, International Health Regulations (2005), third edition (2016).
06Signature
How public health emergencies and epidemics connects the sectors
Select corners to build a signature, then hover a line to read what each sector gives and receives.
Select corners · hover lines6 / 15 relations
Context
Pandemic
Workforce absence ripples from clinics into grid operations, logistics and farm labour.
W · E · I · F · H · B
Sectors
4 of 6
Relations
6 of 15
Coupling
0.41 share of total
Strongest relations in play
Energy → Infrastructure · power for transport and telecoms0.8
Food → Health · nutrition0.7
Infrastructure → Health · access to care0.5
Energy → Food · fertiliser, machinery and cold chains0.5
Teaching values for a typical city-region, not measurements for any place. Coupling is the summed strength of the relations in play, as a share of all fifteen.
07At a glance
At a glance, with 5 related topics
Public health emergencies and epidemics at a glance
risksacademy.comhealth-societydiscipline
Public health emergencies and epidemics at a glance
Open, 1
In preparation, 5
Subtopics, 8
Course codes from the curriculum; study levels L1 to L4.
The Global Centre for Risk and Innovation (GCRI Canada)Health NexusInfectious threats
The Global Risks Forum (GRF)Health and Biosecurity GovernancePandemic governance, Cross border health cooperation, Public health communications, Health system readiness
Start with World Health Organization, then Fraser, then Gostin.
12Questions
Questions, answers and key terms
Is study here free?
Yes. Every course and learning material of Risk Academy, led by the Nexus Consortium, is free to study, self-paced or with a cohort. Ordinary participation has no fee; paid work, internships and fellowships are separate arrangements.
What does completing a course give me?
A completion record: the course, its version, the date and what was assessed, private by default and shared by you. It stacks into discipline, department and programme achievements. A record states what was studied and assessed and does not certify competence; it is not a licence, a professional title or an employment status.
Where do the data and the places come from?
Every faculty teaches on a twin of a real place built from open data; each layer carries its provider, licence and date, and every result on the Academy states its source. Maps and figures are indicators for teaching, never an assessment of a place.
How do I take part beyond the courses in public health emergencies and epidemics?
Form a competence cell of three to seven people, study a shared pathway, take a supervised assignment in the National Working Groups, or bring a cohort from your institution. For organisations.
The rapid capture of reports about potential health events from many sources.
Term
Basic reproduction number
The average number of new infections caused by one case in a fully susceptible population.
Term
Non-pharmaceutical intervention
A public health measure other than vaccines or medicines, such as distancing or ventilation.
ReportsContribute
Contribute evidence from this page.
Reports is the Consortium's quarterly publication. What you know about this subject can become evidence, a case or a correction in the next edition, credited to you and published under CC BY 4.0 where it is your own work.
Risk Academy
Related
Around Public health emergencies and epidemics
Public health emergencies and epidemics
Start with an open course
The catalogue lists each course with its outcomes, labs, hours and level.
Risk Academy is a not-for-profit institution. To ask who funds a piece of work, use the funding questions form.
Independence
Editors and the expert reviewers named on each article decide what we publish. Funders and partners do not review or approve articles before publication.
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