Fire Extinguishers as CO2 and Cooler

hey guys, im just wondering since its summer time and temps get to 100 where i am, is it possible to use CO2 fire extinguishers to supplement CO2 and possibly cool off temps a bit .. i got a great deal from a friend who refills them so im basically getting close to a free refill whenever i need it

the plus side is having high CO2 increases plant resistance to heat so im doing kinda 3 in 1, supplement CO2, cooling air temp, increasing plant tolerance to heat..

so does anyone know if they are purely CO2 or have some toxic material in it too, and if it is possible, does anyone know the cooling capacity BTU of dry ice which is basically what will be used

Can your friend fill a normal CO2 tank that you can fit a regulator on? I wouldn't blast it in there as you will get toxic levels and the plants won't be happy. Any amount of CO2 release that would acutally cool the area will have too high a CO2 PPM.

ive found some tutorials on installing a regulator on a fire extinguisher so i guess it can be done... thought i can blast it and drop some temps though.