text: factors affecting the release and concentration of dust in pig houses?   emmm...think logically: when we call someone a pig, we imply that he is already dusty or dirty. hence, the presence of pigs in pig-houses is the factor that itself stimulates dust concentration.   release pigs from their 'iron cage' of political inactivity, give them essential human rights and you will see a jubilant smile on the dusty face of a pig. the human-like smile...