Project Brief

An exploration of air pollution, its health impacts, and what can be done about it.

This was our final project submission for the CS-171 Visualization course at Harvard Extension School.


We decided to put the reader at the center of journey beginning right in their home city, so they can explore the topic of air pollution around the world from a starting point they can relate to.

In this way we hope to better engage our readers, to make them stop and think about the air we all breathe, and to take action to reduce the damaging health effects and loss of human potential caused by dirty air.

The visualization is separated into three acts:
Act 1: Air
Act 2: Death
Act 3: Action


This project was targeted at a general audience, so our first task was to introduce the concept of air pollution and and convey the urgency of the problem. This was achieved using visual elements such as a pollution slider and introductory video explaining pm 2.5 pollution.

By using a newly published dataset from the WHO comprising pollution data on over 3,000 cities, we were able make our story more relevant to readers in almost every major city in the world. The journey starts with the reader inputting their home city.

The chosen city then appears on a chart of all cities so that readers can see how the air they breathe compares to cities around the world.

With the reader aware of the wider pollution issue in relation to the air they breathe at home, we presented the shocking death statistics from air pollution. This is followed up with a call to action and advice on what can be done to reduce the problem.

Our project was selected for a Harvard Hall of Fame Award
Storytelling with data
3000 cities on a single chart!
Linked views for deeper insights
From data to action


Our project has been viewed by people in 68 countries across 6 continents.

U.S. Department of State now uses our website to support its work on air quality.

The Air We Breathe” website ( includes extensive information about global particulate matter (PM) levels, pollution sources by location, and guidance for the public to help reduce air pollution. Craig’s work on the website is very helpful in visualizing the temporal trends in pollution in cities that host US Embassies and US Consulates.”

- Leslie Edwards, Epidemiologist, Office of Medical Services, U.S. Department of State.

Project Team

Craig Houston / Marius de Vogel / Dominic Peluso