It is the peak of spring allergy season here, as well as other great stuff like air pollution. So I just wanted to share the results of today's testing of my wearable air purifier for asthma. I am lucky to have wooded hills out of my door, so I do not have to scare people while walking there.
The device is two powered respirators merged together to get air flow of 400 LPM. For folks who are not as fat/big as I am, one powered respirator would probably be OK. The thing weighs 10 kilos, but it felt easier to walk with the backpack and enough air flow than in an unpowered respirator mask (or, of course, no respirator at all).
In addition to the two powered respirator cartridges, it also has a activated charcoal scrubber (the big can in the picture) -- for the ozone in the air, and to remove the additional smells that powered respirators themselves introduce (quite ironic).
I tested the efficiency and air flow with the sensors I have. Ambient particle counts went all to zero. Ambient ozone was 35 ppb, and that went to zero as well ( and yes, my ozone sensor has 1 ppb sensitivity 
).
The issue with the exhalation valve (which Gareth commented upon last time) remains. I haven't tried the scuba mask valve yet. For a 45 min walk up 100 m and back it was OK.
Asthma attack from air freshener at work
Has anyone stopped taking medication after symptoms of Allergic Asthma decreased? 
asthma making me nervous to do cardio exercise 
Does regular exercise really give you an advantage if you have an asthma attack?
