One of the coolest things about working in a lab that makes its own hardware and software is the ability to get to find situations to test those products, and I was super happy to be able to getting to test a unique use case for the Touchstone indoor environmental quality sensor we’re working on: monitoring air quality during construction. I recently bought a three-story row house here in Chicago, and before moving in we wanted to do some cosmetic changes – a fresh coat of paint in the third floor bedrooms, brand new carpeting on the third floor as well as on 45 stairs (yes, that’s a LOT of stairs!), and new hardwood flooring on the first floor. All of these projects would be off-gassing various VOCs (volatile organic compounds), and it felt like a great time to bring in a Touchstone to monitor how high these levels got and how quickly they would dissipate. Finally, it also gave the team a chance to test user experience with installation – I am the least tech-savvy member of the bunch, so making sure the instructions were easy to follow was key.

Raspberry Pi SetupTouchstone protoype setupSetup was easy, thanks in part to some of the trickier bits being done by the team before I went to my new house. The setup includes a Raspberry Pi (which I’ve used in other applications, like setting up a welcome kiosk for our Information Services department), a USB stick that allows the Raspberry Pi to talk to the Touchstone, and the Touchstone itself. I also brought with me a Verizon MiFi hotspot, since our internet would not be connected for another week and the system needs internet to communicate to the software component called Grafana. Grafana is a way to display data directly from the Touchstone itself – while we are working on our own software, we are using Grafana to track data for research purposes.

I set up the Raspberry Pi and MiFi in my kitchen on the second floor, and then the Touchstone in the hallway on the third floor.

I set these up the day that painting started, 8/11/17, with final touchups of paint happening on 8/17/17. The units have stayed plugged in since, allowing us to see how the levels “settle” over time. It’s been hands off since installation, except for when we got our internet connected in the house, when I switched the Raspberry Pi over from the MiFi network to its final network home. That process was pretty easy, and the instructions the team wrote were clear and allowed me to do the switch with ease.

What did we learn about VOCs in that time period? As expected, total VOCs went up during construction, stayed elevated during the “worst” parts (when we had paint drying, carpet installing, and the hardwood floor going in simultaneously), and then dissipated rather quickly once we took steps to rid the air of VOCs. We also were able to tell when people were most active near the Touchstone itself, since CO2 levels would raise, which I thought was a funny way of measuring the progress of the carpeting install.

touchstone grafana data

The straight line from the 19th to the 21st is when the unit was offline between taking down the MiFi access point and getting our new internet installed. The 15th was the most active day for installation; the spike on the 18th likely corresponds to the actual move-in date, where lots of cardboard was being tossed around, lots of people were moving around, and any carpet fibers that were buried even after a vacuuming were being kicked up.

We mitigated VOCs in two major ways – creating cross breezes through window airflow, and by constantly running our indoor whole-house fan. We had the air conditioning on during the day – it was about 85-90 degrees during that week, and with workers bustling about we wanted to keep them comfortable – but since we were not living in the house yet, opening the windows at night to let out vapors was an easy and fast solution.

Some things to keep in mind with the graph above – we are tracking four different things that all actually do not usually exist on the same scale as each other, so the end values can’t really be judged without looking at individual points and comparing them to known ranges. But for a quick visualization, this works out great, and being able to track trends is an important part of monitoring indoor environmental quality.

Now that I’m moved in, I am planning on relocating the Touchstone after unpacking to a place that gets a lot of use, like the kitchen or living areas. That way, I’ll be able to directly see the impact had in the areas I “live” in the most. If I do see trends in VOCs or high CO2 levels, I can consider putting some pet-friendly plants that I am researching for part two of our Pocket Guide to Cleaner Air series. While indoor environmental quality sensors won’t diagnose specific issues, they are a valuable tool in tracking your home’s health, just like your Fitbit helps to track metrics about fitness, and we think these metrics will lead to happier home occupants.