HVAC can be elaborated as Heating, Ventilating, and Air Conditioning. These three main functions of heating, ventilating, and air conditioning are basically interrelated. Moreover, HVAC basically depicts the entire cooling and heating system of an air conditioner, including the air filters, humidification controls, duct work, etc.
Yes it can, your duct work is in your attic which is in a very dirty environment and is surrounded by dirt and particles from the outside air. We recommend sealing your duct work and installing a UV light that will provide clean air going through your supply duct work which goes in each room of your home. We install many brands of UV lights and have great success with our customers. Please contact us for more information.