There are loads of air pollution sensors out there - the things that make SmogOff different are that they are calibrated to a council air quality reference station, and have a real time display of the data so people walking by can get an idea of the pollution levels. Like several other systems, SmogOff is open source so others can freely copy the design and/or continue to develop them.
Our previous cloud-shaped design while very lovely was a bit awkward to use - it needed fully dismantling to recharge the battery and get the data off. It would also have been very difficult for someone to build their own if they wanted to. So, we were looking for funding for a long time to improve this. Meanwhile we were being contacted by community groups who wanted to use the sensors and who we were having to put off until we found a way to make the improvements. In late 2024 we lucked out and got some funding to work with 3 of the community groups who'd been in touch - Let's Talk Clean Air In Whalley Range (Manchester), Bike Worcester (near-ish Birmingham), and Lanner Parish Council (Cornwall).
The electronics have been made smaller and neater, and we've redesigned the housing so it could fairly easily be replicated by others who might want to build one. There's a nod to the previous cloud design which we're sad to lose, but hopefully the improvements to usability are worth the reduction in cuteness.
Each SmogOff has a small paperwhite screen on the front displaying real time pollution levels. We have set thresholds on these so if both particulate matter and NO2 are under the WHO 2021 Air Quality guideline annual average exposure limits (5 and 10µg/m³) respectively, a smiley face is displayed (alternating with the actual data values), if both are over the limits a sad face is displayed, and if one is above but the other is below the limits a neutral face is displayed. The smiley face screen alternates with a screen showing the raw values for PM2.5 and NO2.
Now the re-design is done, they've just been shipped out to the community groups. We'll be having a training session soon to show them how to use them, and working with them to design their own experiments in their communities. We're also working on the documentation so people can build their own. Our fab collaborator Dr. Jo Garrett will also be working with the community groups to see how they get on with it all, running interviews at various stages throughout their data collection process. Once it's all done and they have the data they need, the plan is to get the sensors back so we can lend them out to other groups (if they aren't stolen or smashed up... which is part of the experiment!).
This latest work on SmogOff has been funded by the University of Exeter's Civic University Agreements fund.