Volatile organic compounds are chemicals that contain carbon, hydrogen and oxygen and are gases at room temperature. The volatility, polarity, water solubility, and reactivity of a VOC affect the choice of sampling methods.

To assess the influence or relevant importance of various factors in determining the indoor VOC concen- trations it is helpful to use a “source-pathway-receptor” conceptual model. The source is the cause of the presence of the VOC. The pathway is the route the VOC takes to a receptor and a receptor is a person, animal, plant, property or eco-system that is exposed to the VOC. Each factor plays a role in determi- ning the final VOC concentration within the indoor air environment.

In general this conceptual model will also help identify any VOC control strategies that may ultimately be required. Indoor VOC concentrations may be controlled by three basic strategies:

• Source control is the avoidance or elimination of materials that emit VOCs;

  • Ventilation is the lowering of VOC concentrations by replacing air in specific spaces with air (fresh air) that has a lower concentration of VOC (for example, dedicated exhausts in garbage rooms or the pressurization of public corridors);
  • Cleaning includes filtration and ultra (UV) radiation. Filtration is the physical capture and dispo- sal of VOCs. Ultraviolet radiation is the chemical alteration of a VOC compound with the inten- tion of creating different and less harmful compounds. A sampling program may be required to demonstrate the effectiveness of any control measures that have been implemented.