You are looking for a mask to filter particulates, an N95 HEPA mask or should be sufficient, they are usually pink or purple in color. You are correct that a dust mask is insufficient.
If you have a beard, or as I do just think these are more comfortable then you can use a PAPR (pronounced papper) or Powered Air Purifying Respirator.
Here are some examples of the facepieces.
3M™ GVP-Series Loose-Fitting Facepiece L-Series
3M™ Hood BE-10-3 (Formerly 522-01-11R03) White, Regular, Tychem® QC
These hoods are hooked to an air supply, either a pack on your belt that uses filters similar to the ones you wear on your face and blow the air into your mask, or a connected to an air supply that supplies Grade D air to your mask.
Here is an example of a complete system including the air purifying belt pack.
3M™ Breathe Easy™ Butyl Rubber Hood Powered Air Purifying Respirator (PAPR) System, Respiratory Protection FR-57N10, with NiMH Battery and 3M™ Cartridge FR-57/453-03-02R06 1/cs
A better option IMHO mainly because it blows cool air in your face, but it does require a compressed air source.
3M™ Versaflo™ Air Regulating Valve Assembly V-300/37019(AAD)
You can also use an air pump designed to supply the mask instead of compressed air. It plugs into the wall 120 volt and is sitting in an area of clean air and pumps it to the mask.
All of these work without the mask sealing agaist your face, they provide positive pressure inside the mask so outside air doesn't get sucked in. They will constanly blow air outside the mask to prevent contaminates from entering the mask.