Measurement reference · Indoor environments

Understanding Indoor Air Quality Measurements

Different measurements can provide different pieces of information about an indoor environment. No single number represents overall indoor air quality.

What each indicator contributes

Different Measurements. Different Questions.

This reference explains common parameters, their influences and their limits. It is an educational guide rather than a verified list of BioSweep measurement capabilities.

PM2.5

Fine airborne particles

What it is: A size-based category of very small particles suspended in the air.
What it may help indicate: Changes in fine-particle levels that may help direct a source investigation.
Common sources / influences: Cooking, smoke, outdoor particles entering the property and other indoor activities.
Why context matters: The room, activity, outdoor conditions and measurement method affect interpretation. A particle reading does not identify its material or source.

Explore airborne particles

PM10

Larger airborne particles and dust

What it is: A particle-size category that includes fine particles as well as larger inhalable particles.
What it may help indicate: Airborne dust and particle patterns that may be relevant to the concern being investigated.
Common sources / influences: Outdoor dust, movement in a room, disturbed settled dust and building or HVAC conditions.
Why context matters: PM10 and PM2.5 overlap; they are not separate totals to add together. Airborne measurements also do not describe all dust settled on surfaces.

Understand particle size categories

CO₂

Occupancy and ventilation context

What it is: Carbon dioxide, a gas released by occupants as they breathe and also by some other sources.
What it may help indicate: In suitable occupied spaces, patterns can help investigate how occupancy relates to ventilation.
Common sources / influences: Number of occupants, time spent in the room, outdoor air supply and any other CO₂ sources.
Why context matters: Placement and timing matter. CO₂ does not measure all indoor pollutants or, on its own, establish the overall quality of the air.

Understand CO₂ and ventilation

VOCs / TVOCs

Indoor chemical indicators

What it is: Volatile organic compounds are a group of chemicals that can enter indoor air. TVOC is an aggregate indicator whose meaning depends on the method.
What it may help indicate: Changes that may help direct questions about products, materials, activities and ventilation.
Common sources / influences: Paints, finishes, furnishings, cleaning products, stored chemicals and activities in the property.
Why context matters: A broad VOC indication does not identify every compound or its concentration. Questions about a specific chemical may require a targeted method.

Explore VOCs and potential sources

Relative Humidity

Moisture conditions

What it is: The amount of water vapor in air relative to what it can hold at that temperature.
What it may help indicate: Conditions relevant to comfort, condensation and a moisture investigation.
Common sources / influences: Outdoor air, cooking, washing, leaks, ventilation and air-conditioning operation.
Why context matters: Interpret alongside temperature and surface conditions. Room humidity alone does not locate a leak or confirm hidden mold.

Explore indoor humidity

Temperature

Environmental context

What it is: The thermal condition of the air at a particular place and time.
What it may help indicate: Context for comfort, HVAC operation and interpretation of relative humidity.
Common sources / influences: AC settings and schedules, sunlight, occupancy, equipment and room location.
Why context matters: The same property can have different room and surface temperatures. A comfortable air temperature does not establish that other air-quality concerns are resolved.

Formaldehyde

A specific indoor pollutant

What it is: A specific gaseous chemical that may be relevant when investigating certain indoor materials or sources.
What it may help indicate: A suitable targeted method may help investigate a particular formaldehyde concern.
Common sources / influences: Some composite-wood products, adhesives, finishes and other emitting materials; conditions and ventilation also matter.
Why context matters: A general VOC reading is not a formaldehyde result. Appropriate equipment or specialist testing must be confirmed for the required question.

Connect the evidence

Measurements Are Only Part of an Assessment

A measurement is most useful when its method, location, timing and surrounding conditions are known. It may need to be interpreted alongside observations of the property and its systems.

Property conditions
HVAC operation
Ventilation
Occupancy
Moisture
Visible contamination
Outdoor conditions
Timing

A field indicator may help identify a question for closer investigation. It does not, on its own, establish the source of every concern or provide a medical or regulatory conclusion.

Explore a property-led assessment

Ask how a result was obtained

The Method Matters as Much as the Label

Two devices displaying the same parameter may use different methods, settings or reporting conventions. The instrument's suitability, condition and use need to match the question being investigated.

For a specific chemical, hidden source or formal testing purpose, a different method or specialist analysis may be needed. Confirm this before treating a general indoor monitor as the answer.

Read about field measurement and laboratory testing, or explore how to interpret an IAQ finding.

Further reading on the measurement principles

These references explain general measurement principles; they are not statements of BioSweep's capabilities or UAE compliance criteria.

An appropriate next step

Which Conditions Need a Closer Look?

Start with the property concern and the question you want answered. Confirm the relevant parameters, available methods and intended deliverable before arranging an assessment.

Discuss What You Need Assessed