Why does my workshop air feel dusty despite extraction?

Because the extraction isn't capturing all the dust at source, so some escapes into the general air - through poor capture (badly positioned hoods), a degraded system (lost suction or capture), or dust the extraction doesn't reach (hand sanding, dry-sweeping); the dust in the air means the capture is incomplete. Your workshop air is dusty despite having extraction because the extraction isn't capturing all the dust at source, so some of it is escaping into the general air of the space. Extraction is meant to capture dust at the point it's created - at the tool, machine or process - before it disperses. So if the general air is dusty (a haze, dust settling on surfaces, a dusty feel), that dust has escaped the capture and spread into the room, which is a direct sign the capture isn't complete. The reasons dust escapes, often in combination: poor capture at source (the hood isn't positioned or designed to catch the dust where it's released - too far away, wrong position - so dust gets away before it's drawn in); a degraded system (the extraction has weakened - clogged filter, worn fan, blocked duct - so it captures less even while running, linked to lost suction); or dust the extraction can't reach (activities not served by any capture - hand sanding away from a hood, dry-sweeping which throws dust back into the air, disturbed settled dust). Often a dusty workshop is a mix of these. The key point is that the dusty air means the capture is incomplete, and it's worth checking why - the hood positions, the system's performance (which testing measures), and any uncovered dust sources. So because the extraction isn't fully capturing the dust at source. So because dust is escaping capture into the general air. This is general information. This is general information.

A health problem, if the dust is harmful - the dust hazing the air and settling on surfaces is dust people are breathing, and the finest, most hazardous dust (the respirable fraction) is often too fine to see, so visible dust usually means invisible fine dust too; for wood dust, silica and similar, that's a real exposure. Dusty air is a genuine health problem, not just untidiness, if the dust is harmful - which many workshop dusts are. The dust you can see hazing the air and settling on surfaces is dust that's in the air people breathe, so it's an exposure. And many workshop dusts cause serious disease: wood dust is linked to nasal cancer, respirable crystalline silica causes silicosis and is linked to lung cancer, and metal and other dusts cause respiratory disease. So visible dusty air, for these dusts, means people are being exposed to something genuinely harmful. There's an important extra point: the visible dust is only a fraction of what's airborne. The finest, most hazardous dust - the respirable fraction, which goes deepest into the lungs - is often too fine to see. So if you can see the air is dusty, there's almost certainly invisible fine dust in it too, and that fine dust is the most dangerous. This means the real exposure is likely worse than it looks: the visible haze is a sign of a bigger, partly invisible exposure. So dusty air shouldn't be dismissed as just untidy or 'part of the job' - for a harmful dust it's a visible sign of a real health exposure, including the invisible fine dust that does the most harm. It's a warning to act on. So it's a health problem for a harmful dust, not just untidiness. So a health problem - visible dust signals a real, partly unseen exposure. This is general information. This is general information.

Yes - running isn't the same as capturing; the extraction can be on while failing to capture all the dust at source, through poor hood position, a degraded system (lost suction), or dust it doesn't reach, so dust escapes into the air despite the system running - which is why dusty air is a sign to check the capture, not proof it's fine. Yes - extraction can be running and still leave the air dusty, because a running extraction isn't the same as one that's capturing all the dust. The fan being on tells you the system is powered and moving, but not whether it's actually catching the dust at source. Dust can escape capture despite the extraction running for the same reasons the air gets dusty: poor capture at source (a hood too far from or badly positioned relative to where the dust is released, so dust escapes before it's drawn in); a degraded system (the extraction has lost performance - a clogged filter, worn fan, blocked duct - so it captures less even while running, which is the lost-suction problem); or dust the extraction doesn't reach at all (hand sanding, dry-sweeping, disturbed settled dust - dust generated where there's no capture). In all these cases the system is running, but dust still gets into the general air. This is why you can't judge extraction by whether it's on: the dusty air is telling you the capture is incomplete, whatever the fan is doing. So a running system leaving the air dusty is a sign to check the capture (hood positions, the system's performance, and any uncovered sources), not a reason to assume everything's fine because the extraction is on. Testing establishes whether it's genuinely capturing. So yes - running doesn't guarantee capture, so the air can still be dusty. So yes; a running system can still fail to capture the dust. This is general information. This is general information.

Whether the extraction is capturing the dust at source (hood position - close to and over the source), whether the system's performance has degraded (lost suction or capture, which a thorough examination and test measures), and whether there are dust sources the extraction doesn't cover (hand sanding, dry-sweeping) needing better capture or work practices. If the air is dusty despite extraction, check three things. First, whether the extraction is actually capturing the dust at source: are the hoods or capture points well positioned - close to and over where the dust is created - or too far away or badly placed to catch it before it escapes into the air? Hood position is central to capture, so a badly-placed hood lets dust get away. Second, whether the system's performance has degraded: has the extraction lost suction or capture through a clogged filter, worn fan, or blocked duct? This is directly what a thorough examination and test measures - the system's actual airflow and capture - so testing is the reliable way to find out whether, and where, the performance has dropped. Third, whether there are dust sources the extraction doesn't cover: activities or spots that generate dust with no local capture (hand sanding away from a hood, dry-sweeping which throws dust into the air, disturbing settled dust). These need better local extraction, or better work practices (for example, not dry-sweeping a harmful dust but using suitable methods). Between these three - capture at source, system performance, and uncovered sources - you can find why the air is dusty. Testing the extraction is the key step for the first two, and addressing work practices for the third. So check the capture, test the performance, and address any uncovered sources. So check hood capture, test performance, and cover the gaps. This is general information. This is general information.

No - dusty air despite extraction is a sign the dust isn't being fully controlled, and for a harmful dust that means an ongoing exposure; treat it as a warning to investigate and fix (check and test the extraction, address uncovered sources) rather than a condition to live with - a workshop with genuinely controlled dust has clear air. No - you shouldn't just accept a dusty workshop as normal, even though it's easy to. It's tempting to treat a persistent haze and dust on the surfaces as simply the way things are for a workshop that cuts, sands or machines - a background condition to live with. But dusty air despite extraction is a sign that the dust isn't being fully controlled, and for a harmful dust (wood dust, silica, metal dust, and others that cause serious disease) that means people are being exposed to something that can genuinely harm them - including the finest, most hazardous dust that's too fine to see. So accepting a dusty workshop as normal means accepting an ongoing exposure. Instead, treat the dusty air as the useful warning it is: it's telling you the control isn't complete, and pointing you to investigate why (poor capture, a degraded system, or uncovered dust sources) and fix it. Treating it as normal is exactly how an ongoing exposure gets tolerated and allowed to continue. The constructive response is to act on the warning: check and test the extraction to find where the capture is failing, address any dust sources it doesn't cover, and get the general air genuinely clear. A workshop where the air is clear is one where the dust is being controlled - which is the goal. So don't accept it as normal; treat it as a warning to act on. So no - it's a warning to investigate and fix, not to accept. This is general information. This is general information.

No - the visible dust is only part of it; the finest, most hazardous dust (the respirable fraction that goes deepest into the lungs) is often too fine to see, so visible dusty air usually means there's invisible fine dust too, and the real exposure is likely worse than it looks. No - the dust you can see is not the whole exposure; it's only a fraction of it, and often not the most dangerous fraction. Here's why: dust comes in a range of particle sizes, and the finest particles - the respirable fraction, which is small enough to be breathed deep into the lungs - are often too fine to see individually. What you see as a haze in the light, or dust settling on surfaces, is largely the coarser, more visible dust. So when the air looks dusty, there's almost certainly a lot of invisible fine dust in it as well. And the invisible fine dust is typically the more hazardous part, because it's the fraction that penetrates deepest into the lungs, where it can do the most harm (respirable crystalline silica, for example, is dangerous precisely because of its fine respirable fraction). This means the real exposure is likely worse than it looks: the visible dust is both a sign of a dust problem and an under-representation of the total airborne dust, because the most harmful part can't be seen. So you shouldn't take 'it's only a bit dusty' as reassurance - a visibly dusty atmosphere signals a significant exposure that includes the fine dust you can't see. This is another reason not to accept dusty air as normal, and to control the dust properly (and test the extraction), rather than judging the exposure by what's visible. So no - the visible dust understates a larger, partly invisible exposure. So no; the finest, most harmful dust is often invisible. This is general information. This is general information.