I was diagnosed with adult onset asthma after a bout of bronchitis last year. On top of that, I have allergies to most environmentals and I live in a desert environment with dust in the air. So I am considering using a medical mask for most of my day from now on.
What is the most effective use of a mask? Can I still get benefit from it if I only wear it outside and not indoors?
I think that you can order masks online for that purpose. The main thing is that the mask should not allow the allergens to reach your respiratory tract (also the eyes should be protected if you have eye problems because of the allergy). Because the allergens are physically larger than the usual environmental pollutants, masks that block environmentall pollutants will suffice for airborne allergens. Also, common medical masks won't help you a lot.
About using it indors - if you have symptoms even when you are indors, the mask will help somewhat, but it is more practical to eliminate the cause of your problems (dermatophagoides spp. or molds).
I used to have a neighbor that had horrible allergies and would mow and garden in a full white suit that included mask, goggles, and went over their shoes as well. Hopefully you don't get a rash or any other reactions so all you would need would be a mask.
I'd look for a pollen mask instead of a medical mask. There's some reusable ones available that you can wash and they look more like bandanas than masks. Example at Walmart
Medical masks can be absorbent to prevent water droplets that may contain bacteria from getting past the mask. I can imagine how this could be bad for allergies as it might absorb and hold allergens in the mask.
As far as only wearing it outside I think that would be more appropriate than wearing it all the time. Most indoor locations are air conditioned/heated which means air passes through some kind of filter at least. You might look into regularly changing your filters at home or looking into a higher grade of filters if you're having problems inside your house as well.
