[SML] damping echo with blankets

[Pilates For Bodies]

Hello,  we recently shot a video in a ballet room. The echo in this
room was terrible, so we rented five big bags of blankets from a
moving company, and we hung them around two sides of the room.   About
25 blankets in all  A couple days later, I came down with asthma.
This is first time I have every had asthma.  It lasted a couple days.
I can't say for sure, but I think it could be related to the dust in
the blankets. So, I was wondering if there was any material you can
think of that is readily available, cheap and wouldn't have this
health hazard.  Thanks, chris