For the past two months, i've been doing Zwift rides in my basement, as it is relatively cool (73F max) and quite dry (55% RH). In fact, it's actually more comfortable than conditions outside, especially with the Lasko Pro Performance blower (see picture below)


Trouble is, the part of the basement was recently redone, where some bricks were laid done and set (previously, they were loose). The contractor who did this was less than professional, and managed to deposit a film of brick dust everywhere (you can see it in the picture above) from the sanding of the bricks. I think he's actually oblivious to the harms of cutting and sanding of bricks, as he didn't use a respirator! However, I still need to deal with the consequences of his work.

Unfortunately, I didn't realize just how serious things were until I checked the bucket of the dehumidifier, and that's when I realized the entire inside of the dehumidifier was coated brick red. Since his work, I've spent ~6 hours in the basement cycling, without using any respirator protection. I would like to get a better sense of the following

A). How much have I breathed in during those 6 hours. Remember that I have two fans. While the dust did settle, i'm concerned about whatever amount that may have been kicked up
B). Could I use a N95 respirator during exercise? May not be comfortable to wear, but neither is exercising in humidity.
C). Anything else I should do in the mean time?

Thanks in advance