Office Building Odour Complaints: When the Filter Is Only Part of the Story

Office odour complaints can be frustrating because the smell is often strongest in one area, yet the source may be somewhere else entirely. In a corporate building, the filter can be part of the answer, but it is rarely the only thing to check. A good investigation looks at the filtration system, outdoor air intake locations and any internal sources that can release odours into occupied spaces.

Start by identifying the odour pattern

Before changing filters or altering the HVAC settings, gather a clear picture of when and where the odour appears. This helps separate a ventilation issue from a local source inside the building.

Ask a few practical questions:

• •Does the odour appear only in certain rooms, or throughout the whole building?
• •Is it stronger at the start of the day, after lunch, or later in the afternoon?
• •Does it change when the air handling plant starts, stops or ramps up?
• •Is the smell near desks, printers, toilets, kitchens, loading docks or plant rooms?
• •Does the odour worsen when windows are open or when outside conditions change?

If the smell is widespread and linked to operation of the air conditioning, the ventilation path and filtration deserve close attention. If it is concentrated in one zone, an internal source is more likely.

Check whether the filter is doing the right job

Filters can capture airborne particles that carry dust and other contaminants, but they will not fix every odour complaint. A filter that is loaded, damaged, incorrectly fitted or too coarse for the application may allow more odour-bearing particles to pass through than intended.

Look for these signs:

• •visible dust bypass around the frame or holding rack
• •damaged media, torn seals or collapsed filter sections
• •loose fitment caused by the wrong size or poor installation
• •high dust loading that restricts airflow and reduces system performance
• •unusual dust release during start-up or when the plant cycles

If you are unsure of the size, you can use how to measure an air filter to confirm dimensions before ordering replacements.

It is also worth checking whether the filter type matches the building’s needs. Some systems use general dust filters, while others need finer filtration depending on the indoor environment and equipment layout. If the building has specialised zones, such as print-heavy floors or areas with sensitive tenants, our products can help you compare suitable options.

Don’t rely on the filter alone

A well-fitted filter is important, but odours may still enter the system if the air handling plant is drawing in air from the wrong place or mixing in exhaust air from nearby sources. That is why an odour complaint should be treated as a system issue, not just a consumables issue.

Review outdoor air intake locations

Outdoor air intakes can unintentionally draw in odours from car parks, waste areas, delivery bays, kitchens, smoking areas, nearby exhaust fans or street-level pollution sources. If an intake is too close to one of these areas, the building may experience intermittent odours that seem to come from nowhere.

Inspect the intake location and ask:

• •Is the intake near a loading dock, refuse storage area or service road?
• •Could exhaust from nearby plant, kitchens or toilets be recirculating back into the system?
• •Has the surrounding site changed since the system was installed?
• •Are there obstructions, debris or bird nesting activity around the intake?
• •Does the odour line up with prevailing winds or particular times of day?

If the intake location is questionable, the solution may involve repositioning the intake, improving separation from odour sources or adjusting the ventilation design. Site requirements should be confirmed with the mechanical services engineer or building owner, especially where AS 1668.2:2024 is relevant to the ventilation arrangement.

Look for internal sources of odour

Many building odours are generated indoors rather than brought in from outside. Printing areas are a common example. Toner, paper dust, adhesives, solvents and heated equipment can create a noticeable smell, particularly in enclosed or poorly ventilated rooms.

Other internal sources can include:

• •waste rooms and bin storage areas
• •kitchens, tea rooms and dishwashing areas
• •cleaning product storage
• •wet carpet or hidden mould growth after leaks or condensation
• •plant rooms with overheating equipment or insulation breakdown
• •toilets or drainage issues

A useful step is to walk the building when the odour is active. Note exactly where it is strongest and whether doors, partitions or return air paths may be spreading the smell. In some cases, the issue is not that the filter is failing, but that the source room needs better local exhaust, better housekeeping or improved separation from the main air path.

Printing areas deserve special attention

If the smell is strongest near printers or copier banks, check whether those machines are in a shared office zone or a small enclosed room. An enclosed printing area without adequate exhaust can allow odours to spread through return air or open doorways. Moving equipment, improving local extraction or increasing physical separation may help more than changing the main building filter alone.

Make the HVAC system part of the investigation

If the filter, intake and internal sources all seem possible, work through the system methodically. Start with the simplest visible checks and then move to airflow and pressure conditions.

Useful checks include:

• •confirming the filter type and fitment against the equipment requirements
• •checking pressure drop where gauges are fitted
• •looking for damaged seals, loose frames or access door leaks
• •confirming outdoor air dampers are operating correctly
• •checking that return air pathways are not drawing from odour-prone rooms
• •reviewing whether the system has recently been altered or cleaned

Inspection frequency depends on the system, site conditions and dust load. Follow the filter and equipment manufacturer instructions, and monitor pressure drop where gauges are fitted so you can see when the system is drifting out of range.

If the building has recurring problems, commercial filter servicing can help keep the filtration side of the system in good condition, while filter servicing is useful when you need support with replacement planning and fitment checks.

When the filter type needs to change

Sometimes odour complaints point to a filtration grade that is no longer suitable for the building’s use. That does not mean every problem needs a finer filter, but it does mean the current arrangement should be reviewed in context.

A few points to keep in mind:

• •G3/G4/F5-F9 are EN 779 classes, still widely used in Australia, but the standard has been superseded by ISO 16890.
• •MERV, EN 779 and ISO 16890 do not convert directly, so avoid assuming one rating equals another.
• •For higher-efficiency applications, HEPA H13 is at least 99.95% efficient and H14 is at least 99.995% efficient at the most penetrating particle size under EN 1822.

Choosing the right filter depends on the system design, fan capacity, installed space and the nature of the contaminants. In some cases, a better pre-filter arrangement can protect the main filter and improve odour control without changing the final stage.

If the filters need to match an unusual size or housing, custom air filters may be the best way to get the right fit.

A practical way to solve odour complaints

When a building occupant reports a smell, the fastest path to a useful answer is to treat it as a structured troubleshooting task. Start with the complaint pattern, inspect the filter and housing, review intake location, then check internal sources such as printing rooms, waste areas and kitchens. That approach helps you avoid changing parts blindly when the real issue is airflow, intake placement or an overlooked odour source.

If you are managing a building in Brisbane or elsewhere in Australia and need help selecting, replacing or making the right filters, Total Air Filtration can assist. We are a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, and you can call 07 3800 3448 to discuss your needs or request a quote.