What a Gas Sensor Detects in a Workshop With Solvents or Adhesives

When a workshop uses solvents, adhesives, thinners or other chemical products, the air can contain more than just dust. A gas sensor is designed to detect vapours and gases in the air, while a particle monitor only measures airborne solids and liquid droplets. Knowing the difference matters when you are choosing ventilation, filtration and monitoring for the space.

What a gas sensor is looking for

A gas sensor detects specific airborne chemicals or groups of chemicals, depending on the type of sensor fitted. In a workshop with solvents or adhesives, that may include volatile organic compounds, solvent vapours, or other gases released during mixing, spraying, curing or cleanup.

A gas sensor does not “see” dust, overspray particles, sawdust or general airborne dirt in the same way a particle monitor does. Instead, it responds to the presence of gases or vapours that may be part of the work process, or may build up when ventilation is not moving air properly.

In practical terms, a gas sensor is often used to answer questions such as:

• •Is the room building up solvent vapour during use?
• •Is there a noticeable chemical smell because vapours are present, or because airflow is poor?
• •Is the ventilation system removing gases as intended?
• •Are there areas where vapours may collect, such as low points or enclosed corners?

The sensor type matters. Some units are aimed at a single gas, while others are broader and indicate total volatile organic compounds or similar categories. If you are not sure which chemistry is relevant to your workshop, it is worth speaking with the mechanical services engineer, building owner or equipment supplier before selecting a monitoring approach.

Why particle-only monitoring is not enough

Particle-only monitors are useful, but they answer a different question. They show the level of airborne particles, not the presence of gas or vapour.

That means a workshop can have a low particle reading and still have chemical vapours in the air. It can also have a high particle reading from sanding, grinding or overspray while gas levels stay low. These are separate parts of the indoor air picture.

This distinction is important for workshops where chemical use is part of the job, because particle filtration and gas detection are not interchangeable:

• •Particle filtration targets solids and droplets carried in the air.
• •Gas detection targets vapours and gases that pass through standard dust filters.
• •Ventilation control helps dilute and remove both, depending on the system design.

A dust filter can capture particles, but it will not remove solvent vapours unless the system includes the right gas-phase media or another dedicated treatment method. If your site uses both particulate and chemical processes, it is often useful to think in layers: capture particles, move vapours out, and monitor each separately.

Common workshop sources of gas readings

Gas readings in a workshop do not always mean a fault. They may simply reflect normal operations where chemicals are part of the process. Typical sources include:

• •Solvent-based cleaning and degreasing
• •Adhesive application and curing
• •Paints, primers and coatings
• •Sealants and resins
• •Parts washing or wipe-down stations
• •Fuel, exhaust or combustion sources nearby

Some of these products release vapours while they are being used. Others continue to off-gas for a period after application, especially in enclosed spaces or when airflow is limited.

A gas sensor can help identify whether vapours are present before they become obvious by odour alone. That said, odour is not a reliable measuring tool. Some vapours smell strongly at low levels, while others may be less noticeable. A clean-smelling workshop does not necessarily mean the air is free of gases or vapours.

How to read gas results alongside filtration data

Workshop managers and contractors often look at filter condition, pressure drop and ventilation performance. Those readings are valuable, but they tell you something different from a gas sensor.

If your system has pressure gauges fitted, monitor pressure drop to understand when filters are loading up. Follow the filter or equipment manufacturer instructions for inspection and replacement, and adjust checks to suit the site conditions and dust load. That approach is more useful than relying on a fixed calendar schedule.

When you combine readings, the picture becomes clearer:

• •Rising particle levels may point to poor dust capture, process changes or a filter issue.
• •Rising gas readings may point to vapour build-up, poor extraction or inadequate air movement.
• •Stable particle readings but high gas readings suggest the dust filtration is doing its job, while vapour control needs attention.
• •High particle readings but low gas readings suggest the opposite: dust is the main issue, not vapour.

If the workshop has a central ventilation system, it may need both suitable particle filtration and a separate strategy for gas-phase contamination. In some systems, that may involve activated carbon or another gas media stage. In others, local exhaust ventilation may be the more practical path. The right answer depends on the process, the space and the equipment design.

Choosing the right monitoring and filtration approach

Before changing filters or adding a gas sensor, identify what you are actually trying to control. A workshop that sands timber and occasionally uses adhesive does not need the same approach as a spray area, degreasing bench or fabrication space with regular solvent use.

Useful questions to ask include:

• •What chemicals are in use, and when are they released?
• •Is the concern dust, vapour, or both?
• •Is the room mechanically ventilated, naturally ventilated, or a mix of both?
• •Are there local extraction points at the source?
• •Is the current filtration stage designed for particles only, or does it include gas media?
• •Are there filter pressure gauges already installed?

If you are specifying filtration for a commercial or industrial workshop, it is worth checking how the system has been designed against site requirements and AS 1668.2:2024, then confirming the final arrangement with the mechanical services engineer or building owner. That is especially important where chemicals, enclosed spaces or process equipment are involved.

For filter selection, the material and rating need to suit the application. G3/G4/F5-F9 are EN 779 classes still widely used in Australia, although ISO 16890 is now the current standard framework. MERV, EN 779 and ISO 16890 do not convert directly, so avoid assuming a simple one-to-one match. For high-efficiency filtration, HEPA H13 is at least 99.95% and H14 is at least 99.995% efficient at the most penetrating particle size under EN 1822.

Practical signs your workshop may need better gas control

A workshop may be under-controlled for vapours even when the dust filtration looks fine. Signs to review include:

• •Persistent chemical odour after use
• •Staff relying on opening doors or windows to clear the air
• •Vapours lingering around benches, corners or low areas
• •Sensor readings that remain elevated after the process stops
• •Filters that are changing colour from dust loading, but no change in gas readings

If your space is experiencing any of these issues, look at the whole system rather than only the filter element. A better filter alone will not solve a vapour problem if the site needs extraction, source capture or gas-phase media.

Some filters are designed to be washable - check the product instructions. Others are not, and cleaning them incorrectly can damage the media or reduce performance. The right choice depends on the product and the application, not just the frame or size.

If you need to match a replacement filter to existing equipment, accurate sizing matters. Our guide on how to measure an air filter can help when you are checking dimensions before ordering. For ongoing upkeep, see our filter servicing and commercial filter servicing pages.

Getting the right filters for chemical workspaces

Total Air Filtration is a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, established 2009. We work with industrial buyers, workshop managers and mechanical contractors who need filters that suit the system, the site and the type of air contamination involved.

If your workshop uses solvents or adhesives and you are not sure whether you need particle filtration, gas detection, or both, we can help you work through the options and supply or make the right filters for your setup. Call 07 3800 3448 or request a quote.

You can also view our products or explore the industries we supply to see the kinds of applications we support.