Qidi Q1 pro doesn't come with a carbon filter but Qidi does provide a model to print one on their support page. This filter is suppose to be mounted inside of the rear panel which requires removing the rear panel to change the carbon. I designed a rear bracket to hold their filter on the back side of the panel and a fan shroud that goes inside the rear panel to assist in directing air out of the rear vent.

Print the parts in a filament that will withstand higher temperatures such as ABS.  Use organic supports on the rear bracket and print in the same orientation as it is when mounted to the printer.

You will also need some mounting screws for the shroud and rear bracket. I used self tapping m3x8 for the shroud and m3x16 threaded for the rear bracket. 

The Qidi filter can be found on their wiki tech page.