Barry Huang/Reuters

A fascinating new project maps the air quality fluctuations within a city.

The air pollution data we see today typically deals with the big picture - how's the air quality over a particular region? While informative, it doesn't tell you how much pollution you're actually breathing in at a specific moment in your commute or how fresh the air is right outside your house.

But with the latest sensor technologies, that's actually possible.

In a new project called "One Country, Two Lungs," researchers from MIT’s Senseable City Lab gathered fine-grained data in Hong Kong and Shenzhen, two densely-populated Chinese cities just a river apart. Unlike traditional fixed monitoring stations, located in just a dozen places around the city, the researchers used small sensors attached to their wrists and belts. The EcoSense SensPods tracked carbon monoxide, nitrogen dioxide, temperature, humidity, and noise, while the Dylos DC1100 monitored PM 10, a measure of coarse inhalable particles. On their calves, the researches strapped a GPS and camera to track spatial information.

As the researchers made typical commutes - on ferries, subways, and on foot - the sensors captured large fluctuations in personal exposure to air pollution that would go undetected in fixed monitors.


Snapshots of data taken in one location in Hong Kong (top) and Shenzhen (bottom)

The researchers found that air quality is generally worse in Shenzhen than in Hong Kong, an observation in line with fixed pollution monitors in the area.

But it's the fine-grained data that's more interesting. For example, project lead Davide Zilli says they found the air quality in one of the parks in Shenzhen was much higher than expected. "We often go for a run in a park because we think we'll be breathing in some good fresh air. It's interesting to see how that may or may not be true," he says in a phone interview.


This video shows how air pollution data can be presented from a first-person perspective. 

Zilli says in order to make more precise comparisons between different commute paths, though, they'll need to deploy many more sensors - on people,  bicycles, even taxis - and figure out how to account for wind and other weather conditions. 

While the Chinese government explores new solutions to pollution (like building a smog chamber and regulating regional emissions) average citizens still have very little control over how to minimize their own exposure to bad air. Senseable City researchers hope that the individual-scale air quality data they're beginning to gather can place some power back in the people's hands - and feet.

Top image: commuters in Beijing in last month (Barry Huang/Reuters)

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