Type of Dust Mask or Respirator

[mymenagerie]

I'm sure this has been discussed prior... I'm new to forum and couldn't find it: When cleaning coop I use a dust mask, but understand there are different "kinds" or filtration levels. Which one is best? Is a respirator necessary? Does anyone know what a 10 year old could use (regular masks don't fit her face, so I don't allow her to help)? Thank You!

 

[robin416]

None of the masks available in the stores fit me either. I ordered small NIOSH rated masks from a company off the net. They work great except they are hot and being so unltra filtered make it a little harder to breath.