The shop vac is not a dust collection system. Yes, it has a hose. You point it at the sawdust and the sawdust disappears. But the particles that damage your lungs are too small to see, and the shop vac leaves most of them in the air, where they float for hours while you congratulate yourself on the clean floor.
Fine wood dust — particles under 10 microns — is classified by IARC as a Group 1 carcinogen. Same category as tobacco smoke. Group 1 means sufficient epidemiological evidence of cancer in humans. For woodworkers, that's nasal and paranasal sinus cancer from sustained exposure. Not a precautionary classification. Actual data from people who built things for a living.
The shorter-term problem is sensitization. Once your airways react to a species — usually after years of fine-dust exposure — you can develop a reaction at concentrations that would have been irrelevant before. Some people develop occupational asthma. The window between "no symptoms" and "can't work around wood" can close without much warning. By the time it's obvious, the sensitization is established.
There are two dust problems in a woodworking shop. Most people solve one and miss the other.
The first problem is chips and coarse dust at the machine. You can see it. It settles. A dust collector connected to the tool at the point of chip generation handles most of it. Size it for the shop: 1.5–2hp single-stage for a small shop running one tool at a time, 800–1,200 CFM if you're running a table saw, jointer, and planer in sequence. The critical number is CFM at the tool, not at the collector. Long runs of 4" hose bleed velocity through friction. More than 15 feet of flexible hose and you're losing meaningful airflow. Go to a 6" main with 4" drops, use blast gates, and run them closed at the tools you're not using.
The second problem is fine dust in the ambient air — the fraction too small to see, too light to settle, too fine for most chip collector bags to catch. A standard 30-micron bag captures volume. It does not capture the particles that matter. The fine fraction passes through the bag and back into the shop air. This is what most shop dust guides either ignore or bury in the last paragraph.
The solution is an ambient air filter running during work and for 30–60 minutes after: a fan pulling shop air through progressively finer media. The minimal version is a box fan with a MERV-13 furnace filter taped to the intake. Not elegant. Works. A purpose-built unit with staged filtration — coarse pre-filter, HEPA-rated final filter — buys filter longevity and reliability, not fundamentally different performance. Aim for four to six air changes per hour for your shop volume. Mount it at ceiling height, toward the far end from the main dust source, because coarse chips have already settled and the ambient filter is after what's still floating.
Before either of those: the respirator.
An N95 worn during sanding, routing, and cutting fine-grained hardwoods is the most cost-effective respiratory protection in the shop. Under $5 a mask. No ducting. Filters 95% of airborne particles down to 0.3 microns — including the fine fraction the chip collector misses.
A dust mask is not an N95. The paper fold-flat with the single staple filters large particles. It does not filter fine dust. They look alike and feel alike in the shop. They are not equivalent. This distinction matters.
Wear the N95 during the operations that generate fine dust fastest: sanding at every stage, routing, cutting fine-grained hardwoods on the table saw or bandsaw. These are also the operations where chip capture underperforms most, because the fine fraction becomes airborne before the collection port can pull it in.
One BC shop note: when you fire up a propane heater or wood stove, the convection currents from the heat source keep fine dust in motion longer than in a cool, still space. Heat makes the dust problem worse. The discipline — chip collection running, ambient filter on, respirator for fine-dust operations — matters more when the shop is actively heated, not less.
The shop vac earns its place sweeping the floor. It is not a respiratory protection system. Neither is a window left open, or a dust mask worn most of the time, or planning to deal with it properly after the next tool purchase.
Chips settle. Fine dust floats. The stuff you can see is not the stuff that matters.