Services - Additional Detailed Sampling and Testing

Microbial Air Sampling

Spore Trap Air Samples

Air Monitoring is performed when the presence of mould is suspected in a particular area of the structure (e.g. a microbial volatile odor was detected or an area was known to have been previously wetted).  The purpose of such Air Monitoring was to determine the location and/or extent of mould contamination. 

When Indoor Air Monitoring is performed, an Outdoor Air Sample is also collected.  The Outdoor Control Air Test is very helpful in evaluating whether thereis an internally generated mould problem.  Such a problem may exist if Indoor mould tests Report mould levels that are either (a) higher than the Outdoor Control Air Test or (b) present Indoors but absent from the Outdoor Control Air Test.  Depending on the Exterior weather conditions, a Control Sample from an Indoor ‘Non-Complaint’ area may also be used as the Interior Reference.

Air Samples are collected via a Zefon Bio-Pump. This type of sampler uses an Air-O-Cell (AOC) cassette, which is a Spore Trap that captures Viable (living) and Non-Viable (dead) mould spores. Air is drawn through the AOC at 15 litres per minute for 5 minutes, impacting mould spores from the air onto an adhesive cover slip. The AOC cassettes are submitted to an Independent Laboratory.  The impacted cover slips are then mounted on a microscope slide with stain and examined by a Mycologist.  Both spores and hyphal fragments are counted on a fraction of the collective surface (5%) using horizontal traverses.  The count is then converted to a concentration based on the volume of air sampled and expressed as spores or structures per cubic meter of air. 

Viable Air Samples

Viable Air Sampling is performed when the presence of mould is suspected in a particular area of the structure (e.g. a microbial volatile odor was detected or an area was known to have been previously wetted) but could not be identified through a Visual Inspection or Bulk Sampling. The purpose of Viable Air sampling is to definitively identify mould spores by genus and species.  The information obtained through Viable Sampling contribution significantly to the overall picture and interpretation of exposures to mould spores.

Viable Air Samples are collected using an Anderson N-6 impactor. This type of sampler draws air through the impactor at a flow rate of 28.3 litres per minute for 3 to 5 minutes. The particles drawn in are deposited onto the surface of a collection medium (petri dish). The petri dish(es) are submitted to an Independent Laboratory.  The petri dish(es) are incubated in a special incubator that is high in humidity and void of all ambient light and at a Temperature suitable for fungal growth. The incubation period is a minimum of 7 (seven) days for mould cultures to reach their maximum identification growth. After the incubation period, the fungal samples are removed and identified down to genus and to species, where possible, through Visual Identification under the microscope by a Mycologist. Results are provided in colony forming units (CFU’s) per cubic meter of air.