This question was inspired by the Q&A from Cathy who wanted to know about affordable alternatives to HRVs.
We recently bought a house with a bathroom fan unit we can set to run constantly or when humidity reaches a certain level. There's a separate fresh air intake on the side of the house that flows into the HVAC system, and the fresh air gets minimally filtered through the furnace air filter.
We're looking for a unit that would provide us with better filtration, such as a carbon-activated filter that would take out VOCs from outside (we live near an Interstate highway). Some of our neighbors also have their lawns treated regularly in the summer, and we don't want to be drawing those toxic chemicals into our home. We've asked a couple of local HVAC contractors, but they didn't have any suggestions.