Collection: Air Quality Monitors

How to choose an air quality monitor

For dust mite allergy households, indoor air monitoring comes down to four things: humidity, particulate matter, ventilation, and (sometimes) VOCs. Here's what each metric tells you and what to look for in a monitor.

1. Humidity is the priority for dust mite households

Dust mites thrive at relative humidity above 50%. They can't drink water — they absorb moisture from the air. Drop the RH below 50% and the population stops growing; below 40% and it starts to die back. ASCIA and international allergy bodies consistently recommend keeping bedroom humidity below 50% for dust mite control. Australia's east-coast climate — Sydney, Brisbane, the Gold Coast — routinely pushes outdoor RH above 70% in summer, and indoor RH follows unless you actively manage it.

2. PM2.5 and PM10 — what's in the air you breathe

PM2.5 is fine particulate matter — particles 2.5 micrometres or smaller. Sources include cooking, candles, fireplaces, smoking, and outdoor pollution infiltrating through windows. The WHO 2021 guideline is 15 µg/m³ averaged over 24 hours.

PM10 covers larger particles up to 10 micrometres — visible dust, pollen, mould spores. Most monitors capture both PM2.5 and PM10 with the same laser-scattering sensor.

For allergy households, PM readings also confirm your air purifier is doing its job — if PM2.5 stays low when the purifier runs and climbs when it's off, that's your evidence.

3. CO₂ tells you about ventilation

Outdoor CO₂ sits around 420 ppm. When a closed bedroom climbs to 1,500–2,000 ppm overnight, it's a sign the room isn't exchanging air with outside — and humidity is usually building up alongside. The fix is ventilation, not filtration: open a window, run an exhaust fan, improve HVAC airflow.

Look for monitors with an NDIR CO₂ sensor — the industry-standard method. Avoid monitors that "estimate" CO₂ from VOC readings; those are unreliable.

4. TVOC for chemical sensitivities and new furniture

Total volatile organic compounds include formaldehyde (classified by IARC as a Group 1 known human carcinogen), benzene, and solvents from new furniture, fresh paint, cleaning products, and personal care items. VOC spikes are typically short-lived and respond quickly to ventilation.

For most allergy households, TVOC is a nice-to-have rather than essential. For parents bringing new cots or mattresses into a nursery, or for chemical-sensitive households, it's worth the upgrade.

5. Sensor quality matters more than feature count

Two monitors can show wildly different readings of the same air. The reason is almost always sensor quality. The shortcut: monitors using Sensirion sensors for CO₂, humidity, and VOCs are reference-quality. NDIR sensors are the right choice for CO₂. Laser-scattering is the right choice for PM2.5 and PM10. If a manufacturer doesn't specify the sensor type or origin, treat that as a warning sign.

6. Where to place it

• Breathing height — 1 to 1.5 m above the floor
• In the room you use most — the bedroom is the priority for dust mite households
• Away from direct airflow — not under an air-con vent or in front of a fan
• Away from heat and cooking surfaces — distorts temperature and PM readings
• Away from windows — outdoor infiltration will dominate the readings

Once you've measured, what next?

Monitoring is step one. Acting on the readings is step two:

• High humidity (>50% RH) → dehumidifier or AC dry mode
• High PM2.5 → HEPA air purifier sized to the room
• High CO₂ → open a window or improve ventilation. Filtration won't help.
• High TVOC → ventilate; consider a carbon-filter air purifier if chronic
• Persistent dust mite symptoms despite controlled humidity → look at allergen-proof bedding covers and HEPA vacuuming

Read the full buyer's guide →

Air quality monitors are measurement devices, not medical devices. They don't diagnose or treat anything — the readings help you make informed decisions about ventilation, filtration, and dehumidification. For diagnosed asthma, allergies, or chemical sensitivities, please discuss your environment with your GP or specialist.