The rule generally is to pull air through ducting.

This is how I and all the growers I know do it too.

MY ventilation ducting is simple flexible home dePOT duct with booster fans duct-taped to it, lol... looks a little halfassed but works fine. The intake has the fan IN the growroom sucking down a duct from elsewhere, and the exhaust has its duct booster fan at the outer end of the duct.

The fans and ducting are about $40 for each set- 8 feet of hose, a booster fan, and the electrical power cord to convert it (takes less than 5 minutes) to a plug-in rather than hard-wired fan.