What is mold?
Definition of Mold: A multi-cellular, microscopic vegetable plant which forms cobweblike masses of branching threads from the surface of which tiny fertile threads project into the air bearing the part of the plant from which spores develop. Mold may be of brilliant colors or black and white, depending on the type. Molds can develop on leather, cloth, paper, etc., especially in the presence of relatively high heat and relative humidity. See also: FUNGI ; MILDEW.
Molds are simple, microscopic organisms that are present almost everywhere, indoors and outdoors. Mold, like mushrooms and yeasts, are fungi and are needed to break down dead material and recycle nutrients in the environment. For them to grow and reproduce, they only need a food source. Molds are growths that form on organic materials by several different types of fungi. It grows on surfaces in masses that resemble thick layers of cobwebs. There are many types of mold, and they come in many different colors including: black, brown, white, blue, red and green. Molds produce tiny spores to reproduce. The fertile threads of the mold often stand up from the surface to release their spores into the air. These spores, once they are airborne, can remain in the air for long periods of time. They are carried by the air currents, or by attaching themselves to insects or animals.
When mold spores land on a damp surface indoors, they may begin growing and eating whatever they are growing on in order to survive. Mold can grow on wood, carpet, food and paper. The spores of mold are always present in the air and on objects. When the temperature and moisture in the environment are suitable for growth, the spore bursts and grows into a thread-like filament called "hyphae." They use the object they are growing on as a food source, form a mass, and within a short time begin to produce spores. At maturity, spore sacs burst and release spores which begin the reproductive cycle all over again.
Mold grows in areas of the home that are overly moist, have high humidity, low light levels and poor ventilation/circulation. Growth is generally more rapid in the summer than the winter because of the increase in heat and humidity. High temperature, poor air circulation, dim light and accumulated grime assist and accelerate the growth of mold once it has sprouted, but only high humidity and moisture can start and sustain mold growth. If the relative humidity level drops below 70 %, the temperature below 70º F and the object that the mold is growing on loses its high moisture content to the atmosphere, the mold will stop growing and become dormant. But the spores will still remain viable on the host material and become active and start growing again if the humidity and temperature becomes more favorable. However, there are a few common molds that can grow at temperatures as low as 50º F and humidity as low as 45%. Temperatures well above 100º F will kill mold and mold spores, but the exact temperature required to kill specific species of mold is not well established.
How am I exposed to indoor molds?
Every person is exposed to some mold on a daily basis without evident harm. You will commonly find mold spores in the air inside homes, and most of those found indoors come from outdoor sources. Mold spores cause health problems mainly when they are found in large quantities and people inhale many of them. This happens when there is active mold growth in the home, office, or school where people live or work. People may also be exposed to mold by touching contaminated items or eating contaminated food.
What symptoms are commonly seen with exposure to mold?
Molds cause health effects through inflammation, allergy or infection. Allergic reactions, like hay fever, are most common following mold exposure. Typical symptoms reported by people exposed to mold can include, alone or in combination:
- Respiratory problems like wheezing, difficulty breathing, and shortness of breath
- Nasal and sinus congestion
- Itchy, burning, watery or reddened eyes
- Irritated nose or throat
- Rashes or irritation of the skin
Occasionally headaches, memory problems, mood swings, nosebleeds, body aches and pains, and fevers are reported in these cases, but their cause is still not understood.
How much mold does it take to make me sick?
People who are allergic to mold don't all react in the same way in their sensitivity to it, both to the amount and the types that they react to. For some people a relatively small amount of mold spores can cause an asthma attack or bring about other health problems, while others have symptoms that occur only when the exposure level is much higher.
In any case, indoor mold growth is unsanitary and unwanted. If you can see or smell mold in your home, take the steps to find and eliminate the extra moisture and to cleanup and remove the mold.
In some molds, besides their allergic properties, certain types may produce byproducts that have toxic properties. The toxic properties are not always produced, and depend on many different factors both known and unknown. But when the toxins are present, they occur in both living and dead mold spores and might be in the materials that have been contaminated with molds. Remember, when the mold dies and dries up, the spores can become airborne by air currents or handling.
Mold exposure is not healthy for anyone in buildings, so it is always best to find and fix elevated moisture conditions quickly before mold grows and health problems start.
There are some people who are at an increased risk for more severe symptoms, and who might become sick more rapidly than others:
- People with current respiratory problems such as allergies, asthma or chemical sensitivities
- People with weak immune systems from HIV, chemotherapy patients, etc.
- Young children and infants
- And the elderly
Any person that has health problems that they think is due to mold should seek the advice of a medical professional.
Can I prevent indoor mold?
Prevention is a diligent task. You must make repeated inspections for signs and sources of moisture inside, and take steps to eliminate the source(s) of water as soon as possible. The Rh factor, which means your relative humidity, can often be controlled with humidifiers and dehumidifiers. Many things contribute to an increased Rh level, cooking, showers, plants, and drying laundry indoors to name a few. And newer homes are often more airtight and trap water and moisture. One tip to help prevent moisture buildup in the house is to not open your basement windows in the summer. When the warm outside air meets the cool inside air, condensation can form on the basement walls.
To control the moisture level, there are several things that you need to check.
- Be sure that exhaust fans are vented outside, the attic and crawl spaces are ventilated and humidity levels in these areas kept below 50%.
- Evaporation trays in air conditioners, dehumidifiers and refrigerators should be cleaned frequently, and humidifiers should be cleaned according to manufacturer's directions and refilled with fresh water daily.
- Completely clean and dry water-damaged carpets and materials within 24 hours, or consider removing and replacing them. The damaged carpets can harbor mold and bacteria and it is difficult to rid them of those contaminants. The best bet would be to remove them from the building. If leakage or flooding occurs, it is vital that you act quickly.
- Stop the source of the leakage or flooding
- Remove extra water with a wet vacuum or mopping
- Whenever you can, remove the wet items to a dry and well ventilated area to speed up drying. Move and pull up rugs and other areas of wet carpeting as soon as possible.
- Increase the air circulation by opening closet and cabinet doors, moving all furniture away from the walls, and running portable fans.
- Do not use the home's central blower if any flooding has occurred in it or any of it's ducts. Also, do not use fans if mold has already started to grow, if it has been more than 48 hours since the flooding occurred.
- Run any window air conditioners or dehumidifiers at a lower humidity.
- Do not use heaters or turn up the heat in any confined areas as the higher temperatures increase the mold growth rate.
- If water has soaked into the walls, you may need to open the wall cavities, move baseboards, and possibly pry open the wall paneling.
While there is no reasonable way to eliminate 100% of indoor molds and mold spores, you can control mold growth by controlling moisture.