Here is a filtration system for the QIDI Plus 4 which install on the port of the Chamber Circulation Fan where the original carbon system is located. This filtration system uses a HEPA filter and acid free activated carbon pellet to help reduce VOC and fine particle emissions from the printer. It's not a perfect solution but it's much better than what QIDI offers as a solution.

The HEPA filter used is the one compatible with the iLife V3's and V5's robot vacuum cleaners. These filters are easily found and are not expensive.

Here are some Amazon links depending on which country you come from.

Canada: https://a.co/d/6nJDwxg

USA: https://a.co/d/5kqMt2F

For other countries just do a search for HEPA filters for V3S and you will easily find them.

For activated charcoal pellets, use only acid-free charcoal. Using carbon that has been treated with acid can damage your printer by rusting the surrounding metal. Here is a supplier on Amazon who is certified acid-free:

Canada: https://a.co/d/bCy9hJZ

USA: https://a.co/d/gx8MZuJ

The print was made with ASA. Avoid using PLA or PETG because the printing chamber heats up high enough to distort the part. You can use ABS or any filament with higher heat resistance. You can print the model straight up without supports. Fill the container with charcoal pellet and slide the HEPA filter over it. I recommend putting tape on the two holes behind the filter and above the fan to create better suction.