Yes, PVC is very dangerous. But I must disagree on wood. The lignin, which is the major component of wood, burns to carbonmonoxide (which is really toxic and does not smell). It creates aromatic hydrocarbons and lots of fine particulates which can harm your lungs. That means: if you become exposed a lot to the fumes from lasercutting wood, you will become very sick. So be very careful if your hands turn to light red color or if you feel dizzy. If the hand become light red then its carbonmonoxide poisoning. In that case you have to immediately call the ambulance. Other fumes can cause acute asthma. Longtime exposure can cause other really heavy problems. Here is the source of my information: (in german language)

http://www.scilogs.de/fischblog/untersch-tzte-gesundheitsgefahr-durch-holzrauch/

That means: If you cut once in a week and you are working with the window opened then it's maybe okay. But if you do it daily, then it's definitely not okay working without fume extractors. 

However, thank's for the advice with Delrin (also known as POM), this I didn't know before.

How about a soldering fume extractor as base for your filters? It does make a lot less noise than a vacuum cleaner - alternatively a PC fan in a tube?

Not enough pressure. If the cutter is really hard on work, sometimes a flame is shooting out of the material. The fume extractor must be strong enough to get all exhaust out of the box quickly and kill any flames as fast as possible to protect the laser and the lens. That means that a standard soldering fume extractor is not enough. Fortunately there is people growing wheed. I found some pipe blowers, pipes and char coal filters for nice price in the wheed home growing scene. You can't buy that stuff cheaper anywhere.

Worth noting that if you stick with acrylic and wood, then the fumes don't really have any negative health effects. It's still unpleasant, though!

Things like Delrin give off formaldehyde though, and shouldn't be cut without a commercial grade fume extractor. Things like PVC / vinyl give off chlorine gas and will kill you, and even worse, damage your cutter's optics and _really_ shouldn't be laser cut.