You can try without doing an intake port, as you said you have a vent open from what I'm assuming is the heating system. Either way I think a bathroom box fan is an easy solution here, you can tinker with the rest.

As others said the big thing is getting a larger volume of air moving. A quick Google shows an electric air pump moves about 20 CFM where a cheap bathroom fan does around 50 or more. So triple, ish.

Someone else in the comments already did the math for how long it takes to clear a room with different CFMs but I think it's pretty clear an electric air pump is just not gonna cut it.