Mold and Indoor Air Quality
Molds can be found almost anywhere; they can grow on virtually any organic substance, as long as moisture and air are present. Mold can grow on wood, paper, carpet, foods and insulation in homes. When excessive moisture accumulates in buildings or on building materials, mold growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed. It is impossible to eliminate all mold and mold spores in the indoor environment. Mold growth can be controlled indoors by controlling moisture indoors.
Molds produce tiny spores to reproduce. Mold spores float through indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. As molds grow they produce metabolic gasses called MVOCs (microbial volatile organic compounds). MVOC gases that produce the characteristic musty smell associated with mold. The health effects of MVOCs are largely unknown at this time. There is evidence that mold can trigger asthma episodes in sensitive individuals with asthma. People with asthma should avoid contact with or exposure to molds. Some other resources on asthma and mold can be found at:
- EPA's Asthma web site http://www.epa.gov/asthma/index.html
- Allergy & Asthma Network/Mothers of Asthmatics http://www.aanma.org/
- American Academy of Allergy, Asthma & Immunology http://www.aaaai.org
- Canada Mortgage & Housing Corporation "Fighting Mold - The Homeowner's Guide" http://www.cmhc-schl.gc.ca/en/co/maho/yohoyohe/momo/momo_005.cfm
Ten Things You Should Know About Mold
If your community has a mold issue in your school, you should get a copy of the Indoor Air Quality (IAQ) Tools for Schools http://www.epa.gov/iaq/schools/index.html or the asthma companion piece for the IAQ Tools for Schools Action kit, Managing Asthma in the School Environment at http://www.epa.gov/iaq/schools/managingasthma.html
In climates with high humidity combined with winter weather conditions, homes can fall victim to household mildew. Large snowfalls prevents the ground from freezing deeply, or a mild winter can fail to freeze the ground, allowing for easy water penetration. Any rain or melting snow, followed by a humid summer can be a perfect condition for mold and mildew growth.
The terms "mildew" and "mold" are for the most part interchangeable. In some cases they are used in the same phrase: "mold and mildew". The terms are used to describe the physical appearance of common fungi seen growing on objects both inside and outside buildings. This includes solid surfaces such as walls, floors, ceilings, as well as fruits and vegetables (fruits and vegetables are usually referred to as "moldy"). Mold growing on a shower curtain or bathtub is generally referred to as "mildew". Mildew is a term also used by plant scientists to describe plant diseases such as powdery mildew of roses and lilac. There is a difference between the scientific use of the word mildew as it applies to plant pathology and mildew in buildings and on clothing. Mildew on clothing may be and often includes the same mold types that that grow on building materials that we might describe as moldy. Note mildew is commonly used to describe fungal or mold growth in bathrooms and clothing. It is usually a distinction without a difference.
Air can absorb moisture. It's like a sponge and warmer air can hold more water vapor than cold air. When the temperature of the air drops, its ability to hold moisture is lessened until the air reaches the dew point. Droplets of water will form on any surface that is at or colder than the dew point of the surrounding air.
Warm, moist air within a house is attracted to all cold surfaces, including windows, mirrors, exterior corners of a room and inside closets. The buildup of condensation creates the perfect environment for mold spores to thrive.
Mold and mildew can flourish in high humidity, several easy-to-follow preventative tips will keep surfaces, furniture, clothing and other possessions from looking like moss-covered logs. Some the following measures to keep mold levels in you home lower are:
- Keep doors and windows shut during periods of high humidity.
- Circulate air as much as possible through the house. Use portable fans if possible.
- If practical, use a dehumidifier for the house.
- Make sure rainwater or snow melt will drain away from the house. Poor drainage and poor air circulation next to the house will encourage mold and mildew growth. Winds can bring mold spores right in through an open window.
- Unfortunately, mold and mildew are not just summer afflictions. In winter, moisture can collect within a home as a byproduct of burning fossil fuels (such as gas stoves, kerosene heaters or gas fireplaces), cooking, using clothes dryers or taking long showers without venting the stream to the outside.
- When cooking, use lids on pots and pans.
- Make sure air is able to circulate in each and every room. Keep closet doors open.
- Diligently clean the house and its surfaces at least once, preferably twice a year.
- Make sure compost piles are well away from the house. These can produce huge quantities of mold spores than can enter the indoor environment when the wind blows.
- Once mildew appears it is recommended to take quick action. All affected surfaces should be washed with a hydrogen peroxide, chlorine-based or fungicidal cleaner. Do not mix chlorine bleach with detergent cleaning solutions.
CASE STUDIES:
In Alaska there are tribal communities who have done work with indoor mold issues. Of these, the Ketchikan Indian Community and the Kenaitze Indian Tribe are two communities who have addressed the issue of indoor mold in homes.
This project began in February 2008 and will continue for a period of two years. The project began with an initial survey to tribal members on concerns about indoor air quality. After querying the data; it was found that tribal members biggest concerns were the mold/moisture problems in their homes. The program was implemented in the IGAP workplan and it started with a collection of baseline data on the indoor air quality in 14 homes and dwellings. Homes were picked by due to the amount of complaints that were coming from the home owners or dwellers.
Environmental Staff then developed a Quality Assurance Project Plan (QAPP) to initiate baseline data collection of indoor air quality and indoor air parameters to be measured were defined. These parameters are:
* Relative Humidity,
* Carbon Dioxide (CO2);
* Carbon Monoxide (CO);
* VOC’s (Formaldehyde),
* Wet Bulb,
* Dew Point;
* and Temperature.
Other parameters measured and tested: lead and allergens: dust, dander and actual mold.
After all data is collected and analyzed, baseline data that is collected will be for KICHA to help with small remediation’s with the utilization of funding from Housing and Urban Development (HUD). Some remediation may include replacement of windows, supplying de-humidifiers, and or installation of new fans.
The Ketchikan Indian Community also has a an outreach program for mold/moisture to Tribal members that provides information via quarterly newsletters and at Tribal functions. The Kenaitze Indian Community in Kenai, has identified environments with poor indoor air quality from a variety of sources and has conducted education and outreach defining Sick Building Syndrome (SBS). SBS describes a situation in which building occupants experience acute health and comfort effects that appear to be linked to the time spent in a building, yet no illness or cause can be specifically identified. The complaints can be localized in a particular room or widespread throughout the home or building. Poor indoor air quality can lead to increased health problems causing reduced productivity due to discomfort or increased absenteeism from work.
Their outreach gives a general overview of the most important maintenance and housekeeping items that tribal members can do to improve the health and durability of their homes. The following were their recommendations in a community newsletter.
- Clean and disinfect appliance drip pans regularly to reduce contaminant growth and exposure.
- Keep your basement or crawlspace dry to avoid mold, mildew, and rotting problems.
- Clean dirty air filters. A dirty air filter will be ineffective in cleaning the air and will spread contaminants throughout the house.
- Keep your furnace or other fuel burning appliance maintained and have it checked regularly to avoid combustion air contaminants.
- Repair broken or leaky pipes to keep mold from growing in concealed spaces.
- Inspect chimneys and vents for soot stains, cracks, or improper fits that could leak combustion gases.
- Reduce humidity levels with proper ventilation.
They also define good indoor air quality in the Tribal community as a healthy indoor environment where the surroundings contribute to productivity, comfort, good health and a sense of well being. They stress to members that there are many benefits to good indoor air quality, the most obvious is the health of the building occupants. Rusty Swan is the housing director contact at the Kenaitze Indian Community.
In early March 2003, the Cold Climate Housing Research Center (CCHRC) was contracted by the HUD Office of Native American Programs to do a rapid survey of mold problems in alaska native housing. By mid-March 2003 they had contacted 73 of 88 regional or village housing authorities in Alaska. In total, they documented over 1700 apartments or homes that had some level of mold problem. They determined that the mold was in varying stages from mild mildew around windows, in kitchens or in bathrooms to severe mold development that would require the destruction of the building. HUD recognized the seriousness of this issue and is providing training to housing workers at Tribal Housing Authorities around the Nation. The CCHRC identified and educated Tribal Housing Authorities that adequate ventilation is one of the keys, along with good moisture control, to maintaining a healthy, mold-free homes.