The question comes down to what the landlord represented to you and/or what is in the lease. If the landlord had represented (or told) you that the space had the proper ventilation and/or that the landlord would install it--but that  was not true--then if that representation was one which it was reasonable for you to rely upon, you may be able to void the lease owing to the misrepresentation. (Though note: if you had the opportunity to inspect the space, you may be expected legally to have done your homework and "due diligence" and verified such an important representation yourself; i.e. it would not be reasonable to rely just on what the landlord said.) Or if the lease promised the proper ventilation system, then if that is not present or installed, that is a breach of the lease which may let you terminate the lease.However, without a representation by the landlord or a lease provision about ventilation, you would seem to have no grounds to get out of the lease. If you leased the space without making sure of ventilation and without the landlord promising it, that is, unfortunately, your problem, not the landlord's, and you would be obligated to the lease.The landlord is not obligated to put in the ventilation system unless it was part of the negotiations or lease; it's your business, not the landlord's, so the landord does not need to subsidize it.