Why does my room get extremely dusty in a few days? please help?

I don't know whats wrong wtih my room it gets extremely dusty in a few days and can get annoying cleaning every few days. I close my windows all the time, I taped my vents. I'm not sure why it gets dusty? My brother keeps like five computers in his room on 24/7, his windows are always open etc and his room has no dusty he never ever cleans his room. Please help me? I don't think its my skin either(like dead skin turns into dust) cause i use lots of lotion and my skin isnt dry..