One of the easiest things to do is to regularly change the filters in your heating/cooling systems. You may also want to consider humidifiers/dehumidifiers as they can maintain humidity at a very even level which greatly impacts comfort.
A second step would be to have our NATE-certified professionals come to your home to perform an air quality check. We offer a variety of Daikin products including whole-home air purifiers, ventilators and ultraviolet lights that can help your family breathe easier.