As succinctly as possible, 3D printers are in the same area as gas stoves. They definitely put off lots of small particles into the air, but the science isn't clear enough for outright FDA regulation. If you use a stove all day, say at a restaurant, then of course that needs to be ventilated, and the same is true of a 3D printer. If you don't use either 24/7, then it's a judgement call. There are few studies on the actual damage from plastic fumes because who wants to subject a bunch of families to plastic fumes? Sure, breathing in melting plastic is bad for you, but how bad exactly when dispersed throughout a house"?
We take two approaches to air quality management. Venting is cheap and effective since it relies on the fact that the lung-damaging particles are so small they drift along with the air. By keeping negative pressure on the enclosure, the particles are swept along through the vent to the outside, giving the best possible indoor air quality. This is approach taken by our large industrial lasers. There's actually a 1 ft x 5 ft hole in the front of the laser to give the largest volume of air flowing through the laser and to the outside.
If you can't vent to the outside, there are a variety of qualities of air filtering.Using a filter is less safe because the air is returned into your breathable airspace, but may be good enough for many situations. We provide a carbon filter that removes enough VOCs that we can't measure them, but may not remove smaller particles that only a HEPA filter can handle. Good quality air filters capable of getting both sizes of particles run $500 dollars and up and are a speciality unto themselves. Should you want to go with an industrial grade air filter we can custom design and attachment for you.
We believe our two solutions cover 95% of the needs out there, especially for non-commercial 3D printer usage.