The best set up I came across was a pump that mounted on your waist, it pumped in filtered air and kept a positive pressure under the mask. I snaked the tube up under my leathers between my shoulders. Wasn’t too cumbersome.

I’ve seen the one you’re talking about. I thought it was too much weight to be carrying on my neck all day.

But unless you’re prepared to go full hazmat you’re getting exposed to foul air.