They are a bit on the more expensive side, but I have set up a few shops and garages which have a series of inlet and outlet powered louvers which are controlled by a CO sensor or set of CO sensors in the shop.
Once the CO level gets above a preset level, the louvers open up and turn on exhaust fans, once it drops below a lower preset level, the louvers close and the exhaust fans turn off.
For a shop that was 80 x 140, we had 4 48" x 48" louvers on either side of the shop... I I imagine 4 36" louvers w/ exhaust fans would be sufficient for the purpose of your shop, though it would definitely be more expensive than just hooking up exhaust vents.