you could you put a carbon filter on the intake and out take.They are light proof and it will keep the air coming in clean and the air going out clean
Thats how i keep my light in to prevent stunting growth in flower.HTG has some 60$ ones that work good
or you could build your own
Ryoko Builds a DIY Activated Carbon Filter - 30 Minutes, $30 Dollars - The Garden's Cure