No intake.. what happens?

Basic Growing Info
1

Hi,
I saw this easy build on spacebuckets

[Album] Space bucket launching into flower - Album on Imgur https://imgur.com/gallery/k4OBlhttps://i.imgur.com/XHid4ps.jpeg?fb(image larger than 700 KB)

It appears there Is no intake at all. How can the plants grow so well, and is there anyway to just put a carbon sheet and have it absorb the smell as it goes out? The fan might be pulling from the spacers, even though they fit tight.

Also, what is the screw in led equivalent of his bulbs, 20w?