Air knowledge

Understand what is in the room.

Air quality is not one number. Learn how particles, gases, moisture, biological growth and ventilation create different problems—and why they require different responses.

Start here · Three everyday readings

PM2.5, TVOC and humidity—without the jargon.

These three readings describe different parts of indoor air. One is about particles, one is about gases and one is about moisture. Understanding which number moved helps you choose the right response.

Fine airborne particles moving towards an air purifier

01 · Fine particles

What is PM2.5?

PM2.5 means airborne particles 2.5 micrometres or smaller. Smoke, haze, combustion particles, traffic pollution and fine dust can fall within this size range.

What is below it?: PM1 and ultrafine particles are still smaller fractions within the broad PM2.5 category.
Why care?: These particles can travel deep into the lungs. A higher reading calls for source control, reducing outdoor entry and effective particle filtration.

Understand PM2.5 and haze →

Visible indoor emissions illustrating airborne gases and irritants

02 · Airborne gases

What is TVOC?

TVOC means total volatile organic compounds. It is a combined signal from many airborne gases that may come from paint, adhesives, new furniture, cleaners, fragrances and cooking.

What does it tell me?: A rising reading can point to a new emission source or insufficient ventilation; it does not identify one chemical.
Why care?: Some VOCs can irritate the eyes, nose and throat. Remove or reduce the source first, then ventilate where appropriate.

Understand formaldehyde and VOCs →

03 · Moisture

What is humidity?

Relative humidity is the amount of water vapour in the air compared with what the air can hold at that temperature. It is shown as a percentage, or % RH.

What range matters?: Keep indoor humidity below 60%. Persistent readings above that level are a reason to find the moisture source.
Why care?: Excess moisture favours condensation, mould and dust mites. Very dry air can also feel uncomfortable to eyes, skin and airways.

Understand humidity and dampness →

Do not read them as the same problem. A particle filter can lower PM2.5 but does not dehumidify the room. Moisture control does not remove VOC sources. A TVOC sensor is useful for trends, not as a laboratory identification of individual gases.

Particles + allergens