Yeah, you can get the cheapo 30 cents mask, or get a real respirator and control the air you consume.If the house is worthy of a respirator, perhaps you should walk away.

And lastly, if you are going to be vacuuming or sweeping when cleaning up after mice, make sure to wear a N100 rated dust mask or respirator to avoid breathing in dust that is contaminated with hantavirus. 

When you take a pulse, pressure, respiration's they are yours.

PS - Home Depot has a good respirator (not mask) that's designed for mold.  

I dawned my respirator and started spreading powdery death. 

They also wear respirators. 

When local authorities advised the use of N95 respirator masks and encouraged people not to go outside unless they had to, we followed suit and handed out face masks to our tenants and passed along the advisory to stay indoors during the days when the air quality was poor.4.

I give my guys respirators and pull all the sheetrock down, then hit it with bleach. 

If I  have to tell my future tenants that they must wear a respirator all day, in order not to huff diesel and gas fumes, that's gonna be a problem.

That means, usually, N95 paper resirator dust masks (you get them cheap in bulk on Amazon) and a standard half-face painter's respirator with removable cartridges.