Cool. So we could get air quality apps for the phone or smartwatch?
> Discover the PurpleAir PIXEL, one of the first end devices featuring the BMV080 particulate matter sensor for precise local air quality measurement. This user-friendly device provides real-time PM2.5 readings with a quick response time, clearly displayed via LED indicators. The BMV080‘s fanless design ensures completely silent operation, making it both effective and unobtrusive.
https://www2.purpleair.com/products/purpleair-pixel
That's the form factor you'd be looking at when its included with the rest of the supporting circuitry and logic.
So... possibly might be able to get it into a smaller package if the data display is externalized (Purple Air uses LEDs).
My parents are interested in this as one of their use cases is to put it on their e-bike so that they can be made aware of worsening air conditions after they've left the house.
Cost is one, but this isn't something you can measure quickly on demand, you want to keep averaging multiple measurements over time. So unless you want to hold out your phone for minutes to get a measurement it doesn't seem practical.