Use point source ventilation on the machinery causing the odor/smoke, not just ventilating the room. If you ventilate the room, you're still breathing in all that crap as you're between the oven and the fan. We use a variable speed fan on our oven ventilation so in the winter when we're running product that doesn't cause fumes we can turn it down/off and make use of the heat, and in the summer we can dial it up to get that heat/fumes out of the shop.