Building low-cost air pollution monitors at Georgetown University

Students in the School of Foreign Service discover the promise and pitfalls of DIY air quality sensing.

May 23, 2018 · 3 min read

Air pollution is one of the largest public health challenges the world faces today. In 2015, polluted air was responsible for over 4 million deaths worldwide, the 5th-highest risk factor for death globally. Its economic impact is also enormous: as much as 0.3% of global GDP is lost due to outdoor air pollution. Sadly, both mortality and economic impacts from air pollution have been steadily rising and will probably continue to get worse.

While some governments are taking action to address the problem, many are not. There are lots of reasons for this, but one of the most important is a systematic lack of air quality data in many parts of the world. This isn’t as surprising as it might seem once you realize that a single EPA-grade air quality monitor can cost as much as $20,000 and requires trained staff to operate. With that price tag, it’s no wonder that many countries and cities are unable to afford a robust air quality monitoring network.

Completed air quality monitor built by students at Georgetown University. The device is capable of measuring PM2.5, temperature, and humidity, and uses WiFi to transmit data to the cloud. The total cost is under $150.

This is what makes low-cost air quality monitors so important. Cheap sensors and electronics, widely available cellular networks, and inexpensive cloud-based data storage mean that it’s now possible to build basic air quality monitoring systems for far less. Of course, these devices aren’t anywhere near as accurate as EPA-grade ones, but they can still provide useful information.

This spring, students at Georgetown University’s School of Foreign Service (SFS) learned about these monitors first-hand, by building and testing fifteen of them. With very little engineering or computer science background, the students wired sensors, programmed a microcontroller, and conducted real-world experiments to measure air pollution in their community. STIA 315: International Air Quality Lab was one of SFS’ “Centennial Labs” on the occasion of its 100th birthday. It was also my first experience teaching at Georgetown. I’m incredibly grateful to SFS for being willing to support this experimental, highly multi-disciplinary class, and for embracing the value of hands-on STEM education. Also, the class wouldn’t have been possible without the active support of the Georgetown Maker Hub, which provided vital space, equipment, and technical know-how throughout the semester.

Finally, I’m very grateful to the excellent and intrepid students — many of whom were graduating seniors — who were willing to take the class! They did a tremendous job, and I’m proud of how much they accomplished in one short semester. Each one has written about their experience, including important lessons for anyone interested in better understanding the potential for real-time, individual air quality monitoring. For more information on the air quality monitor design and testing, the resulting data about air quality in the Georgetown area, and insights on improvements for the next generation of devices, check out the students’ write-ups below.

Further information about the air quality monitor is available on GitHub and Thingiverse.

Colin McCormick

Written by

Technologist, physicist, energy policy expert. Georgetown University, Valence Strategic, World Resources Institute, Conservation X Labs. I also play trombone.

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