Apart from the reply you've already received, most the bad stuff like plastic nanoparticles in the air and many hard to detect VoCs are also rather blatantly an issue with PLA and other filaments.

People focus too much on smell as the only indicator.

That's largely a myth.

This review [1] cites the absolute highest amount of emitted styrene in the studies they are reviewing to be 113 μg/min. Using [2] for simplicity with styrene's molar mass (104.15 g/mol), we get to a printer creating at most 0.024 ppm of styrene per minute per m3 of unchanged air. For comparison, the "work exposure limit (WEL) for styrene is currently 100 parts per million (ppm) averaged over an 8-hour day" [4].

In other words, as long as you have some air exchange in the room, you'd be orders of magnitude away from the safe work exposure limit on styrene.

It also makes sense, considering that it's a microscopic amount of molten plastic, whereas injection moulding factories work with vats of the stuff.

[1]: https://www.sciencedirect.com/science/article/pii/S135223102...

[2]: https://teesing.com/en/tools/ppm-mg3-converter

[3]: https://en.wikipedia.org/wiki/Styrene

[4]: https://www.hse.gov.uk/plastics/faqs.htm

Most filters have limited effective life for VOC, and "safe" use is measured in a few hours at most. Venting outdoors into a fern/decorative-plant filled yard is the preferred option for both FDM and Resin printers. Most activated charcoal filters just reduce the smell, and do nothing about the the harmful parts even with HEPA14 filters etc.

Chopped CF filled FDM filaments are mostly a scam, but there are few PETG and ASA viable options:

https://www.youtube.com/watch?v=w7JperqVfXI

https://www.youtube.com/watch?v=m7JAOi4JnBs

https://www.youtube.com/watch?v=vAL_p0yYKIc (Fibre Seeker 3)

One challenge designing a metal-printing process was making it safe for people without prior lab-safety training. Some 3D additive processes are simply just not practical for careless "yolo" consumers. =3