Brian, It's an interesting topic, and you should for sure not decide to reject this idea for your thesis because you feel that it is only a partial solution. You are not responsible for fixing the whole world, and your relatively small intervention might snowball by bringing to light the problem. This might stimulate others to think about other aspects of the problem. Certainly, poor people are not going to turn down work, even if there is a long-term health risk associated with a job, so the point is to make an impact in a way that is practical.
If I were you, I would be spending more energy thinking about how you can actually create a product that will achieve your goals. What will be different and better about your product as compared to other things that already exist? Are you talking about making a new kind of respirator that is particularly well-suited to protecting against off-gassing from industrial processes that call for melting metals? I'm sure such products already exist. Why aren't they currently being used in this environment? Is it that people don't know its dangerous, they don't care, or they don't have the money, or something else? These are the kinds of questions you need to be asking yourself right now. Is there some local material that could be used to make the equipment very cheaply? Would it be plastic, and if so, do you have the skills necessary to produce a prototype here at Parsons? Would this involve making molds and then producing resin castings? You are getting to the point in the process when you need to make some very practical decisions, based on an honest appraisal of what you want to be working on for the next 8 months. steven