Sonoff AirGuard PM2.5 & PM10 Air Quality Monitor | SAWF-07P

Dust is the part of indoor air you cannot see. Between traffic, generators and construction, a closed apartment in Lebanon can hold far more fine dust than it feels like. The AirGuard PM2.5 puts a real number on it, on a large screen you can read from across the room.

It measures PM2.5 and PM10 particles and refreshes every two seconds, so you see the effect of opening a window or running a purifier almost immediately. Temperature and humidity sit on the same screen, and a small light on the corner changes colour with the air quality, so you get the answer at a glance without reading anything.

When the air crosses the level you set, it can beep, change the indicator light, and send a notification to your phone. You choose which of the three you want, so it can be loud in a nursery and silent in a bedroom.

It keeps a year of readings that you can export, which is what makes it useful beyond the first week. You can see whether the air is worse in the evening, whether the new filter actually changed anything, and which room is the problem.

It runs on Matter over Wi-Fi, so it joins Apple Home, Alexa, Google Home and SmartThings directly and can trigger other devices – a purifier plug, a fan, a notification – without a hub.