Carbon filters for odor control is often needed to be installed on the air outtake and attached to light hoods to pull hot air outside. I have several friends that have found that by exhausting air outtake through their furnace, water heater, or sewage stink pipes is the easiest solution.
Room Volume= Length x Width x Height
The rate of air exchange is measured in cubic feet per minute (CFM). For every cubic foot that is blown out of your room an equal amount of cubic feet of air must be brought in. Low air pressure will cause your plants to grow poorly, and anyone working in that room for that matter. Airflow should be met with the least possible resistance whenever possible. Turns, bends, and reductions in ductwork will reduce the CFMs, so try to keep the duct moving in straight lines whenever possible and use the widest pipe or flex ducting.
When a vent pipe is not easily installed, you can use existing ventilation in your home. Regardless of what you tap into, backflow is the main concern. Back flow preventers can be installed between where you tab in the appliances exhaust to keep all air moving in the right direction. Hot air will rise up and inline fans might be needed.