Industrial straw and strawless pig housing systems (7500 pigs in each one) were compared in respect to emissions of odorogenous and toxic compds. The highest av. concns. in air were obsd. for 2-Me pentane, PrOH, PhH, 1-BuOH, cyclobutanol and MeSH (above 100 mu g/m(3)). The system without straw litter showed lower air pollution hazard than the straw housing system.