Newer, simpler, more robust version of SMOG, temperature, humidity and pressure sensor: https://blog.jokielowie.com/en/2018/01/do-it-yourself-simple-smog-sensor/
In several countries, there is now a kind of citizen-science initiative where citizens can work together with the official environment government agencies to help collect data, for example:
- in the Netherlands: RIVM https://www.samenmetenaanluchtkwaliteit.nl/
- in Belgium: http://ik-adem.be/
- in Germany: http://luftdaten.info/
Would be nice to forward your data to one of these (if there is such an initiative in your country).
The inexpensive sensors used here are probably not as accurate in absolute terms compared to the official measurement equipment, but they can make up for that in the density of the measurement grid.
I think that - especially the guys from Germany do it much better -
using the same sensor. My goal is to make in the simplest way possible, and then go from there to more complicated projects. This particular sensor is actually quite good, but requires < 70% humidity to work correctly.
This quick project is for sure very cheap and perfectly suitable for indoor use. I’m running it also successfully for outside - but with very short tube (ca. 10 cm), which makes up a bit for not heating up the incoming air. At least the data is not far off the regular state gov approved SMOG station.