Last time we talked about the dust, pollen and small particles in the air that can cause irritation. They can generally be captured with the right type of filtering media. A sub-class of airborne irritant is bio-aerosol. Examples of that would be mold pores, air-borne viruses etc. They are airborne particulates that can cause sickness for the occupants. Depending on the specific particle size, a high MERV filter media may be able to capture some of it. However, if the occupants have low immunity, there are products available with a ultra-violet light option to kill some of the germs.
The third class of irritants is odors that come from household cleaning products, paint, smoke, pets etc. Conventional filter media will not be able to help much because the particles are too small. If it is a common problem the homeowner should consider a carbon or chemical filter to remove the odor.
It is also important to note that the two irritants above exist as symptoms of problems that occur in the house. To truly rid of the problems effort must be made to identify the source of the irritants and address it if at all possible. As a home performance contractor Sandium have the resource to place a monitoring device in your home to track the air quality over a period of time. That way we can identify the problems in a scientific way and come up with a plan to address them.