If you can smell the kiln room, you're breathing it

That sharp smell during a glaze firing isn't “just the kiln working.” As clay and glazes climb past 1,000°F, they release fumes — sulfur compounds from the clay body, decomposition products from glaze materials and colorants, and fine particulates. If you can smell it, those compounds are in your breathing air, and a firing cycle runs for hours.

The symptoms are the warning system most potters learn the hard way: headache, nausea, or eye and throat irritation during or after a firing. If any of those show up, the ventilation isn't doing its job — stop and fix the setup before the next firing.

The standard fix is a downdraft vent: a system that mounts under the kiln, draws air down through the firing chamber, and ducts it directly outdoors — not into the attic, not into the garage. Most kiln manufacturers sell vent kits sized for their models, and a vent also improves firing consistency.

Until one is installed, fire in a separated space (garage with the door open — never a sealed living area), keep the kiln room closed off from the house during firing, and don't hang out in the kiln room: check on it and leave. And non-negotiable either way: working smoke and carbon monoxide alarms in the kiln area.