Air Quality and Safer School Streets

Frome Town Council have asked for our help in monitoring the effect on air quality of their Safer School Streets trial. This is due to run for 18 months from April 2024, with the aim of encouraging active travel and reducing car use, particularly around the school run.

FTC would like to site several (perhaps about a dozen?) sensors in the areas covered by the trial to see how the air quality is affected by the hoped-for changes in behaviour. This needs to start as soon as possible in order to build up a ‘before’ picture.

There are 2 parts to this:

  1. Relocate some of the existing monitors that are no longer needed in their current locations, and
  2. Build some more: FTC would like us to quote for building 10 more from scratch.

For 1, I’ve contacted several of the hosts from our monitor-building workshop, to see whether they’d like us to relocate their monitor. This has yielded 2 or 3 monitors for relocation.

For 2, we need an up to date list of components with prices (10-off) and lead times for ordering them. If the resulting cost is OK with FTC we would then need to go ahead and build them, either ourselves or in the form of another workshop.
(Oakfield School have a keen and active STEM club and they have already been doing some air-quality-related projects, so they might be interested in getting involved.)

We could also do with some help with visualising and interpreting all this data. Possibly the publicity around Safer Streets will tempt a data scientist and/or air quality expert out into the open!

I’ll chase down the monitors for relocation. Any offers of help in other areas – updating the costs, building/upgrading monitors, printing off the plastic parts, participating in a workshop, etc. – gratefully received!

For example, what the heck is going on in Keyford today?
Screenshot from 2023-12-02 17-16-33|690x441

Screenshot from 2023-12-02 17-15-44

'tis the season for log-burners!

Indeed. Except this seems to have kicked off around 1am, and quieted down over lunchtime. Intriguing!

Happy to print and build. I also have a spare sensor

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Maybe The Crown burned the lunch?

Happy to run a workshop at the school if that’s the way we go.


No, it’s the other way round: Maybe whoever had been piling old tyres onto their bonfire since 1am took a lunch break :grin:

I could try helping with the visualisations and data interpretation. I might just need a bit of guidance.


That’d be great!

I know someone in Keyford, I could ask her if she noticed a bonfire or wood burner smoke. Where exactly is the sensor located?

Happy New Year everyone. A couple of updates:

  • I’ve collected a couple of monitors that were no longer being used. Once they’ve been updated they can be re-deployed for Safer school Streets

  • Katie at FTC is keen to get some more monitors built, so as a first step we need an up-to-date BoM and estimated cost.

From Katie:

"Just wanted to touch base with you with regards to ordering new parts, lead times etc. I’m keen to get things moving, especially if there might be a bit of a wait. We are still hopeful that the scheme will start on 15th April and so, would be great to get some data before then. The Somerscience Festival, in which Oakfield pupils hope to participate, is on 6th May, so I’ll need to give them something definitive soon.

“Anything I can do to assist with gathering existing sensors or ordering parts, please let me know.”

Hello all!

Firstly, thanks so much for your kind offers to help with printing, building and workshops. Much appreciated! The STEM club at Oakfield Academy are a great bunch. They’re really thirsty to learn and very excited about this project.

As Al mentioned, I’m really keen to get going with this asap. We really need to have a good bank of data prior to the Easter holidays to make the project worthwhile for Our School Streets evaluation.

Is someone please able to advise on how we order parts, the cost and the lead time?

Many thanks in advance,


Hi Katie,

Sorry for the delay in getting back to you, I’ve been reasonably busy lately.

I’m working based on my understanding of an aim is for 10 devices for this project.
After going through some returned devices, reusing parts & gathering components we already have, several complete or near complete devices (some needing 3D prints, powers adapters, some missing more components).

I’ll aim to get up to date costing of components/consumables for the remaining build this week.

I don’t believe we’re missing any components that are only available on long lead times, but will need to confirm. The 3D printed parts have some delay due to the time taken to print, but it’s hours per print, not days, so more dependent on availability of reliable printers & filament.

If there are any parts on offer, or looking like there is a lead time, I’ll order them ASAP.

I also still need to test/program/setup the data side for all of these as they’re completed, so they’re ready to be deployed.

I think last time we did components at cost, with no direct charge for work done, but a suggested contribution to help keep Tech Shed running.


In the meantime, a bit of info which may help with activities for students:
We use to store our data, so (aside from our visualisations on there will be raw data available if needed.

Depending on what level the STEM club are at, they may be able to use opensensemap’s API to pull in data for their own projects.

Hi @KatieFTC

I’ve ordered all the parts to meet 10 units, with the exception of 3D printer filament.

Latest delivery is currently on the 26th Feb - if it looks like that date will be missed, were may have to order from more expensive suppliers with UK stock, but I’m hopeful we’re covered.

Do we have sites selected to host the sensors?


Has anybody considered using optical methods for detecting pollution? I saw this instrument. It keeps tracking the sun, and measures the absorption spectrum of polluting gasses. System Description - Aerosol Robotic Network (AERONET) Homepage I had a look at the manufacturers website, and from what I can glean, it has a number of photosensors at specific wavelengths. So the spectral resolution is not very detailed. But seems to be what the customer is happy with. The standard model has 9 bands in the range 340 nm to 1640 nm

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This module measures 410 nm to 940 nm in 18 bands: SparkFun Triad Spectroscopy Sensor - AS7265x (Qwiic) (SEN-15050) — Cool Components Add a couple of servos for azimuth and elevation movement, and a 4 quadrant sun tracker, plus ESP32 or whatever, and that would do?

From Katie, FTC:

Curtis Shaddick who runs the STEM club at Oakfield has suggested Friday 15th (ideally) or Friday 22nd March for a workshop from 3-4pm to build sensors. Do either of these work for you? I can attend either (or both) with you.

Please indicate your availability to attend:

  • Friday 15th March, 3-4pm
  • Friday 22th March, 3-4pm
  • can’t manage either
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Is the air quality sensor able to distinguish between types of particles? For example, can it distinguish between smoke particles and pollen or fungal spores?
Can it detect water mist / fog?