Interior Air Quality (IAQ)
Children, the elderly and those with weak immune systems, or who suffer of asthma, allergies or respiratory diseases, may be more vulnerable to an exposure to biological or chemical pollutants found in the interior air. Reactions may vary according to the degree of exposure and general health of the person; asthma, allergic reactions, irritations, headaches, nausea, acute or chronic intoxication. Canadians spend about 90% of their time inside (at home, work or in leisure), the interior air quality (IAQ) is therefore a priority.
It is possible to establish a link between health and place of living when certain conditions are observed:
- The same symptoms are manifested in several individuals occupying the building;
- The symptoms begin or increase after moving into a new building; following a major water leak, renovation work, or following the purchase of furniture, rugs or other materials that can emit chemical substances. These symptoms appear in a place where poor ventilation, in a specific location or following a change of season.
- The symptoms disappear or diminish after the person concerned leaves a given place during a period of 1 to 2 days.
The occupant often has an idea of the type of contaminant to which they are exposed to. They can therefore guide an IAQ expert that could:
- Diagnose the problem;
- Identify the cause;
- Recommend appropriate corrective measures
The factors to be considered during an investigation are in relation to:
- The behaviour of the occupants of the building
- The presence of certain chemical products
- A ventilation problem
- The presence of excessive humidity or stagnant water
- The presence of devices using fuel (heating or various motors or tools)
The three principal types of contaminants observed in buildings are:
Chemical (volatile organic compounds (VOC), formaldehydes, carbon monoxide, etc.): an inspection is necessary for the diagnosis, measurement of physicochemical parameters are carried out (CO, CO2, VOC levels), the objective being to determine the source of the contamination).
Particulate (asbestos fibres, fibreglass, silica sand, etc.): specific air tests are carried out, notably for asbestos. The source is often traced back to the construction materials present in the building
Biologic (mold, yeast and bacteria): being that the contaminant is a living organism, the investigation is more complex. In this case, the objective is to investigate and characterize the air inside the building to confirm the presence of a fungal contamination (mold and/or yeast) and/or bacterial.
No exposure limit has been established by the law in the case of mold. Therefore, the recommendations are based on current industry rules and practices. In general, these recommendations are based on the protocol of New York, the directives of the Canadian Mortgage and Housing Corporaption (CMHC), of the Canadian Centre for Occupational Health and Safety (CCOHS), and the Institut National de Santé Publique du Québec (INSPQ).
Mold is a micro-organism similar to mushrooms and yeast and is part of the fungi group. Mold is ubiquitous and is part of natural decomposition processes. Its growth is dependent on the organic material available to be decomposed, on the temperature and the degree of humidity.
Mold reproduces by sporulation as soon as its living environment becomes unfavourable. After the spores are produced, these will spread in the environment and can create new mold colonies.
According to the INSPQ, the inhalation of these spores can cause health problems. However, mold is not harmful. In fact, according to the Canadian Centre for Occupational Health and Safety (CCOHS), in our area, there are about 100 000 different types of mold and were are exposed to them on a daily basis. Therefore, the effect of mold on health depends on a multitude of factors such as individual sensibility, age, previous exposure and/or existing predispositions that are specific to each individual.
According to the INSPQ, the investigation of a fungal contamination should be based on the two following principal objectives:
- Verify, and locate if possible, the existence of a fungal contamination in the hopes of intervening as fast as possible to decontaminate the building and correct the situation that is propagating the contamination;
- Verify the presence of health problems in the occupants of the building related to a fungal exposure, and if possible orient them as fast as possible, according to the severity of the case, to the resources of the health system.
1- Interviews and questionnaires to establish a sampling strategy, the type of sampling and the methods of investigation to be used.
2- Inspection of the building and its contents to detect visible mold and to determine water infiltration sources or specific locations to be investigated.
3- Direct reading of physicochemical parameters to determine if humidity, temperature, ventilation conditions are favorable to the development of mold, yeast and/or bacteria. The level of carbon dioxide (CO2) The level of carbon monoxide (CO) The level of relative and specific humidity in the air Air temperature Humidity of the material Thermographic inspection with the help of a thermal infrared camera.
4- Sampling to determine the type or species of the biological material collected.
- Air sampling by impaction on agar media
- Sampling of the material in bulk
- Sampling by impaction on a cassette (spore trap)
- Samling with sponge
- Samling with adhesive tape
- Samling of deposited dust