I think most air pollution that you see in the home could be from those that smoke in the home or from a external source. I would hope that having a good filter in the HVAC system you house may have would be a great help to reduce the amount of air pollution that is within your home.
So, we just had our heat pump and air conditioning system replaced and I learned that you should get your air ducts cleaned every few years. They were absolutely filthy and we were breathing that. The guy said no filter filters everything out of the and a lot of what isn't filtered lands in your ducts. Some of that can actually grow in there.