1 - PARTICULATES are air pollutants that have mass, such as: vehicle emissions, pollen, dust mite carcasses and feces, pet dander, cigarette smoke and candle char.
2-  BIOBURDEN is biological material, living or dead,  in the air, such as: bacteria, viruses, mold spores and fungi.  These materials could cause allergies or spread diseases.
3- V.O.C.'s (VOLATILE ORGANIC COMPOUNDS) is the gas state of chemicals.  In your home they come from household materials and cleaning products.  V.O.C.'s are released from: paints, perfumes, plastic, furniture and carpets, glue to name only a few.