For both new and existing homes, health is directly linked to the air quality of the house. A house with poor air quality is known as a "sick" house.

Poor IAQ can lead to a variety of issues for both the occupants and for the home itself. Occupants may become ill from mould and air born pollutants and the house may retain moisture that can lead to structural damage.

Pay particular attention to signs of poor IAQ in existing homes, and when working on a new home be aware of the products being used and the work being done. Ensure proper procedures are being used and that there is adequate ventilation in the spaces where off-gases and air born pollutants/toxins may be present on the job site.

IAQ in a home is directly related to moisture and humidity levels, and any newer products in the home that have the potential to off-gas and release chemicals into the air.

IAQ is also effected by the airtightness of the home and how often the stale indoor air is replaced by fresh outdoor air.

New homes are tighter, and have less natural air changes which means pollutants and toxins and moisture may remain in the home longer. Also, more manufactured products are used in home construction which can off-gas and release harmful pollutants and toxins into the home, especially if the air/vapour retarders are not installed properly.

The Moisture / Mould Connection

The presence of dampness can lead to mould growth which results in health problems.

Uninsulated and cold surfaces (windows, outside corners, closets on outside walls, carpet on concrete) often become damp and over time begin to grow moulds.

MOISTURE is the key to MOULD GROWTH

Moulds produce odours, spores and mycotoxins causing headaches, respiratory problems, asthma and allergic reactions. Mycotoxins from dangerous moulds can be very dangerous to infants. Moulds are nature's way of breaking down organic matter.

Factors that affect germination and growth of mould are:

• Food
• Temperature
• Oxygen
• Water

Mould growing inside a house may affect IAQ and the health of the occupants. Eventually, mould will also recycle within the house affecting the durability of the house.

Mould Clean-up - For minor amounts ONLY

The following steps should be taken to clean up small amounts of mould:

• Discard mouldy items
• Clean and decontaminate site
• Eliminate the moisture sources
• Warm any cold surfaces
• Maintain regular cleaning
• Eliminate standing water
• Maintain appropriate RH within the home

NOTE: Any large amounts (more than 1/2 sq.ft.) of mould should be cleaned by a professional at the earliest opportunity. It would also be appropriate to request that a professional be brought in to determine the cause of mould and perform any actions required to remove and prevent mould in the future.

You should NEVER install insulation over existing mould or evidence of water/moisture ingress.

Mould does not grow on glass fiber insulation, it grows on organic material, in the case of batt insulation this normally means dust and dirt.

The IAQ strategy:

1. Remove or eliminate
2. Seal or isolate
3. Ventilate - stale air out fresh in
4. Filter (particles and gases)

Strategies for controlling mould:

• Find the moisture, find the mould
• Remove mouldy building materials
• Discard mouldy items
• On solid non-porous surfaces clean up mouldy areas with unscented detergent and water (or specialty product like conbrium, etc.) then clean up with a HEPA vacuum. On porous surfaces such as wood, the use of specialty products, procedures and specially trained technicians may be required. In extreme cases where the product cannot be removed or replaced it may be necessary to use a method called iceblasting in order to kill the mould.
• Correct the sources of moisture - roof leaks, foundation leaks, plumbing leaks, moisture buildup from daily living
• Keep relative humidity low enough to prevent condensation on windows
• Use bathroom and kitchen exhaust fans and consider installing better ventilation
• Consider using a dehumidifier in the basement in warmer weather

Common Contaminants on the Job Site

Pollutant	Description	Sources	Symptoms
Formaldehyde	Colourless gas; has pungent odour in high concentrations	Synthetic fabrics in furnishings, rugs, drapes, glue or processed wood products, smoking UFFI	Nose, throat, and eye irritation; carcinogen.
Volatile Organic Compounds (VOCs)	Usually not visually detectable but often have a detectable odour	Pesticides stored in the house, hobbies, crafts, adhesives, solvents, cleaning products, building materials	Nose, throat, and eye irritation
Respirable Suspended Particulates (RSPs)	Microscopic particles that are suspended in the air	Unvented and inadequately vented gas appliances, kerosene heaters, construction materials, dust, smoking by-products	Nose, throat, and eye irritation, respiratory infections, bronchitis
Carbon Dioxide (CO2)	Colourless and odourless gas	Improperly maintained or vented combustion devices, smoking, occupants	Headaches, fatigue, increased heart rate
Carbon Monoxide (CO)	Colourless and odourless gas	Spillage from combustion appliances, fireplaces, air intakes from attached garages, smoking	Nausea, headaches, blue fingernails, disorientation (can kill)
Ozone (O3)	Colourless and odourless gas	Improperly installed or maintained electronic air cleaners, copy machines, computer printers, ozone generators	Coughs, chest discomfort and irritation of nose, throat, trachea
Radon (Rn)	Colourless and odourless gas	From soil through cracks in basement walls or floor; weeping tiles open to house air; dirt floor	Linked to lung cancer
Nitrogen Dioxide (No2)	Colourless and odourless gas	Combustion product, exhaust back-draft, flue/chimney leaks, cracked furnace heat exchangers, unvented kerosene and gas space heaters	Nose, throat, and eye irritation; shortness of breath, respiratory infection, emphysema

What to look for in New Homes - Evident Smells:

• VOC's: paints, glues and solvents
• Formaldehyde: furnishings, drapes, carpeting
• When working in new construction it is important for you to wear the appropriate protective equipment and have adequate ventilation to ensure your health.
• Mould does not grow on glass fibre but will grow on

What to look for in Existing Homes - Evident Smells:

• Old house smells (earthy, musty, mouldy, damp newspapers, etc.) imply biologicals that are linked to dampness and moulds
• Wood smoke, creosote and oily fumes are some of the many indicators of combustion spillage and must be corrected
• If these conditions exist you should consider requesting the owner have a specialist investigate and possibly mitigate the situation prior to the installation of insulation
• Tightening a home that already shows signs of mould or other indoor air contaminates may lead to a significant decline in the indoor air quality and the health of the occupants