| Sample Location Zone Category |
Definition |
| Zone A |
Samples are obtained at vapour entry points into a building (e.g., breach in foundation, sump hole). Samples are used to identify areas of point- source vapour emissions into impacted structures and/or for investigative/health screening purposes; typically, an instantaneous grab sample, though sample volume may need to be metered to avoid overwhelming the analytical system. |
| Zone A-1 |
Soil gas samples. Samples are obtained from temporary or permanent subsurface probes; typically an instantaneous grab sample, though sample volume may need to be metered to avoid overwhelming the analytical system. Care must be exercised to avoid short-circuiting the sample pathway by the use of a high sampling vacuum or flow rate. Care must also be exercised to avoid or prevent entrapment of groundwater. |
| Zone B |
Samples taken in unoccupied (and unfinished) areas on building levels in contact with the soil. Little personal exposure is expected. This sample could be an instantaneous grab or time integrated sample. |
| Zone C |
Samples taken in occupied finished part of the building level in contact with the soil. Some personal exposure could be expected, depending on the extent of the area’s use. This should be a time-integrated sample. |
| Zone D |
First floor living area. Personal exposure level depends on percentage of time occupied and whether sleeping quarters are located on this level. Time-integrated samples are appropriate. |
| Zone E |
Second or higher floors. Occupied during sleeping or other hours. This zone needs to be considered if there is a major contaminant situation, if there is a direct-air connection with the level of entry or if it is occupied by an unusually sensitive receptor. Time-integrated samples are appropriate. |
| Outside/Ambient |
Used to assess the influence and impacts of outdoor air quality on indoor air quality. Also can be used as an additional quality control sample because background ambient air concentrations of volatile petroleum hydrocarbons are at well-documented average levels at most locations. Time integrated samples are appropriate. |
