Thanks everyone for advice. Iīve obviously read the LE threads about ventilation using the "Search"
and among various suggestion I have choosen this one, which seemed pretty simple and working for some of you...it didnīt work for me, thatīs why Iīm asking... here is the picture...
Thanks for the suggestion about drinking and breathing - it is true, one is so concentrated...and it may also be my case
My troubles are definitely not caused by lack of fresh air as I have a window on the opposite side of the room, serveral metres from the exhaust...
