Indoor air often contains higher concentrations of hazardous pollutants than outdoor air. In general your home has none of the protections that nature has to clean pollutants out of the air. So other then waiting for late spring and early fall to vent the air in your home, what can you do?
The first thing you need to do is take a look at the sources of pollutants in your home. Some include every day chemicals such as cleaning products and pesticides. However their other sources such as cooking, bathing materials, and any issues associated with heating or air conditioning your home.
Regular maintenance of your heating and AC system will help knock these off as issue spots in your home. Every 10 years or so it’s also good to have your vents cleaned and it’s best to have this done by professionals.
Regarding the other sources of contaminants in your home. Well, take a two front approach. First, make sure you your daily do diligence in making sure vents are on when using cleaning products and that everything is stored properly when not in use. Outside of that, consider getting a properly rated HEPA filtration system.
Of note, you can get HEPA filtration systems that are stand alone units, or ideally link into your existing ventilation system. Personally I am a fan of the later method as you knock out particles before they enter your duct work, which helps keep them cleaner longer, plus your air conditioning and heating system circulates air through out your home, so on central location can take care of your whole home which is better and cheaper then individual units in each room.