This is an important area as dust in the air of brooder sheds appears closely associated with infection with infection of young chicks.
Dust is most likely to be raised when litter is being removed or raked over. In these cases it would be worth lightly damping down the litter so dust is not raised when it is moved
Good quality litter will also help. A coarse litter of wood chips or pine wood shavings appeasers to work well litter that is already dusty may only contribute to the problem