If there’s one thing that feels like it’s gotten worse in my lifetime, it’s air quality.
Colorado’s air quality last week was dismal, filled with smoke from Canadian wildfires, making Denver’s air quality among the worst of any major city.
This is what happened to air quality four miles from my house:
And here’s the air quality index (AQI) in my bedroom:
You can see spikes from cooking. And you can see the moment (2023-05-19T22:25 MDT) I swapped out the aging filter on my little LEVOIT air purifier, holding particulate in check, returning indoor air quality to baseline.
Why care about air quality?
Acute exposure to air pollution makes you acutely dumber.
This was the conclusion of MIT researchers back in 2022 when they looked at the effect of air quality on chess.
They combed through 30,000 chess moves, evaluating them with the Stockfish chess engine, comparing 121 players against themselves under different air quality conditions (which they monitored with foobot sensors).
The researchers concluded that an increase as small as 10 µg/m³ PM2.5 causes a 2.1% increased likelihood of player error.
Measuring air quality
Reference particle mass counters cost thousands of dollars. And even so-called low-cost air sensors like the ubiquitous PurpleAir will set you back $200.
But the same sensors used inside the PurpleAir, the PlanTower PMS5003, can be found for as little as $15 on AliExpress.
The Plantower sensor, however, is far from a reference device. But studies suggest it’s directionally correct. And, with after-the-factory calibration, it can match readings from more expensive reference meters1.
The Plantower PMS5003 features in AirGradient’s DIY printed circuit board (PCB), which combines air quality, temperature, and CO2 sensors with a cheap ESP8266 for internet. I ordered ten of these PCBs from PCBWay back in 2021 for about $30.
I’ve since modified AirGradient’s example code to support pushing data to Home Assistant via MQTT. From there, sensor data gets sucked up by Prometheus, so I can monitor it via Grafana.
This system gives me a full view of my indoor air quality. And it’s a needlessly complicated way of reminding me to change out my air filter 😬.