Moulds and Other Allergens
These biological chemicals can arise from a host of means, but there are two common classes: (a) moisture induced growth of mold colonies and (b) natural substances released into the air such as animal dander and plant pollen. Moisture buildup inside buildings may arise from water penetrating compromised areas of the building envelope or skin, from plumbing leaks, from condensation due to improper ventilation, or from ground moisture penetrating a building part. In areas where cellulosic materials (paper and wood, including drywall) become moist and fail to dry within 48 hours, mold mildew can propagate and release allergenic spores into the air.
In many cases, if materials have failed to dry out several days after the suspected water event, mould growth is suspected within wall cavities even if it is not immediately visible. Through a mould investigation, which may include destructive inspection, one should be able to determine the presence or absence of mould. In a situation where there is visible mould and the indoor air quality may have been compromised, mould remediation may be needed. Mould testing and inspections should be carried out by an independent investigator to avoid any conflict of interest and to insure accurate results; free mould testing offered by remediation companies is not recommended.
There are some varieties of mould that contain toxic compounds (mycotoxins). However, exposure to hazardous levels of mycotoxin via inhalation is not possible in most cases, as toxins are produced by the fungal body and are not at significant levels in the released spores. The primary hazard of mould growth, as it relates to indoor air quality, comes from the allergenic properties of the spore cell wall. More serious than most allergenic properties is the ability of mold to trigger episodes in persons that already have asthma, a serious respiratory disease.
Mould is always associated with moisture, and its growth can be inhibited by keeping humidity levels below 50%. Moisture problems causing mould growth can be direct such as a water leaks and/or indirect such as condensation due to humidity levels.
Famous quotes containing the word moulds:
“The little toy dog is covered with dust,
But sturdy and stanch he stands;
And the little toy soldier is red with rust,
And the musket moulds in his hands.
Time was when the little toy dog was new,
And the soldier was passing fair;
And that was the time when our Little Boy Blue
Kissed them and put them there.”
—Eugene Field (18501895)