What we like
- Displays a particle reading alongside temperature and humidity
- Offers PM2.5 and PM10 modes with local sound and light alerts
- A year of history and export available through eWeLink
What could be better
- Does not measure CO₂; IKEA ALPSTUGA adds it at a lower listed price
- Needs continuous USB-C power and clear rear vents
- Alexa lacks numeric particle readings and humidity over Matter
Good for watching particles, with a clear omission
SONOFF AirGuard PM2.5/PM10 makes sense when you want to watch particle readings during cooking or compare the room before and after running an air cleaner. Its screen keeps the selected particle concentration visible, with temperature and humidity below it. That is more immediate than another sensor whose information is hidden in an app.
At a listed $39.90 in SONOFF's US store on September 9, 2026, with tax marked included and shipping extra, it is reasonably priced for that focused use. But it does not measure CO₂. A low particle reading does not tell you the carbon dioxide level, so do not buy it as a substitute for the AirGuard CO₂ model.
For a general room monitor, that omission makes the cheaper IKEA alternative especially relevant. For a particle display with Wi-Fi and configurable alerts, AirGuard still has a useful role.
Several readings at a glance, but one particle mode
The monitor offers PM2.5 and PM10 modes, with manufacturer-specified updates every two seconds. Its display shows the selected particle measurement alongside temperature and humidity. It does not show both particle concentrations together, despite having both modes.
The buzzer and colored indicator are useful when you want the monitor to attract attention without checking a phone. eWeLink provides alert thresholds, light brightness and scheduled quiet periods. Being able to quiet the alerts matters for a device intended to remain in the room all day.
The hardware is less flexible about placement. It needs continuous 5 V USB-C power, and the rear vents must remain clear. The 70 × 103 × 26 mm body is designed to stand on a desk or shelf; SONOFF advises against mounting it flat against a wall. A visible cable is part of the purchase.
Alexa leaves too much of the data behind
SONOFF's current Matter table lists numeric particle readings, temperature and humidity in Apple Home, Google Home, SmartThings and Home Assistant. Apple humidity requires iOS 26 or later. Alexa receives temperature and an air-quality level, without the numeric particle concentration or humidity.
We would not choose this combination for an Alexa dashboard that needs precise particle values. The screen still shows the measurement, but the main reason for connecting that sensor would be missing from the selected platform.
For a longer record, eWeLink stores up to a year of particle, temperature and humidity history and supports export. That is useful for examining patterns over time. The history and detailed alert settings are eWeLink features, rather than a promise of identical charts and controls in every Matter app.
Choose the display, or choose broader coverage
IKEA ALPSTUGA, listed at $34.99, combines CO₂ and PM2.5 with temperature and humidity. It requires separate USB power accessories and a Thread border router for connected use, and its screen shows one selected reading at a time.
ALPSTUGA is the stronger feature-value choice if you want both CO₂ and particles and already have Thread. AirGuard earns its place when the simultaneous display, PM10 mode, Wi-Fi connection or eWeLink alerts and record are the features you will use. Paying for AirGuard should be a deliberate choice of those benefits, not an assumption that every air-quality monitor measures the same things.
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