My powered mask stopped hayfever and other respiratory symptoms when mowing long grass

Spent 2 long hours of mowing tall grass this afternoon. Didn't seem to be much dust as the grass was wet from heavy rain over the last 3 days. At first I didn't use the CleanSpace. However after 30 minutes I had a terrible attack of sneezing and coughing with watery eyes.  I returned to the house and got the CleanSpace and wore it the rest of the afternoon. Wow!   Stopped sneezing and hayfever symptoms completely. Brilliant!