We have a really, really old version of one of these.  http://solutions.3m.com/wps/portal/3M/en_US/3M-PPE-Safety-Solutions/Personal-Protective-Equipment/Products/Product-Catalog/~/Powered-Supplied-Air-Respirators?N=5158350+8690968+3294529207&rt=r3      I used it a few years ago when I had powdered sulfur to load on a windy day.  The air from the hood puffed up a standard paper spray suit so I looked like the Pillsbury Doughboy, but my eyes were not burning and tears were not running down my face.  Filters for different types of hazardous materials are available.