Charted: Global air pollution

Data can help government officials anticipate when air pollution levels may reach unhealthy levels, even in areas that are not monitored.

A new map showing hourly air pollution levels in over 250 cities could be a useful tool.

The World Air Map gets over 500,000 open data measurements from 11,000 sensor stations every day. It uses this data together with artificial intelligence and machine learning algorithms to estimate pollution levels in remote areas that may not be monitored by reading stations.

In select cities in the US and Europe, the AI model can give hourly forecasts of pollution over the next day.

“These models also anticipate long-distance transport of air pollutants, helping strengthen forecasting accuracy in urban areas,” according to the makers of the map, Plume Labs. In March 2015, the tool identified high levels of pollution in Paris, when the city’s index shot up above any others monitored by Plume Labs.

This led the city to make public transport free, lower the speed limit, and impose odd and even-numbered license plates on alternate days. Each city is marked with a hexagon on the map, with larger ones for more highly populated areas. The darker the colour of the hexagon, the more polluted the city is.  

Clicking on a hexagon brings up an “air report” of the city with its current and average air quality index, and index of pollutants including ozone, nitrogen oxide, particulate matter, and sulfur dioxide.

The index is categorized into four levels of pollution and their associated health risks to make it easier to understand - fresh air, moderate, high, very high, or extreme pollution. Each city report also gives recommendations for daily do’s and don’ts based on the quality of the air.

There are currently four activities - outdoor sports, cycling, bringing your baby out, and eating outside. For each of the activities, the report recommends residents “take care”, “take it easy” or “go for it”. The map is paired with an app, a handy way for urban residents to get personalized alerts on pollution levels.

The World Air Map can be viewed on this website: air.plumelabs.com. The app is available for Android and Apple phones.