[m4r1k]

I'm also an AirGradient user. AirGradient prioritizes accuracy and it's fully OSS. The sensors are fully replaceable; not if but when they eventually lose accuracy. I'd argue that monitoring PM2.5 levels indoors is even more crucial than outdoors. In our home, we have good air recirculation and HEPA filters in every room. Since we began keeping indoor air clean, our spring allergies (and general allergy issues throughout the year) have become much less severe. IMO AirGradient is the best way verify current levels and ultimately ensure the filtration works. https://imgur.com/a/UIkkANL