ALL ABOUT MOULD -PART 2

                                                                   How Mould Grows

Critical Requirements: There are four critical requirements for Mould growth –Mould spores, food, proper temperatures and considerable moisture. Removal of any one of these items will prohibit Mould growth.

1.       Mould Spores.  Ranging in size from 3 to 40 microns (human hair is 100-150 microns), Mould spores are everywhere. There is no reasonable, reliable and cost-effective means of eliminating them from environments that humans inhabit. So, trying to control Mould growth through the elimination of Mould spores is not feasible.

2.       Mould Food.  Almost any substance that contains carbon atoms (organic substance) will provide sufficient nutrients to support Mould growth. Even the oil from your skin that is left when you touch an otherwise unsuitable surface, like stainless steel, or the soap residue left from a good cleaning will provide sufficient nutrients to feed some Moulds. The most common materials found in homes like wood, paper and organic fibers are among the most preferred of Mould nutrients. Thus, eliminating Mould food from the environment is a virtually impossible task.

3.       Appropriate Temperatures.  Most Moulds grow very well at the same temperatures that humans prefer 77-86° F (25-30°C). In addition, temperatures close to freezing are not cold enough to prevent Mould growth nor are desert-like temperatures. Therefore, it is not feasible to control Mould growth in our home environment through the control of temperature.

4.       Considerable Moisture.  Barring Xerophilic Moulds, most other Moulds require the presence of considerable moisture for growth. Various species of Mould have different moisture requirements. The vast majority of Mould species require water levels equivalent to moisture content corresponding to a relative humidity of at least 70 percent. In fact, the great majority of serious, large Mould outbreaks inside buildings occur where porous, cellulose-type materials have literally been kept wet by liquid water or sustained condensation.

Human beings prefer humidity below the critical relative humidity for Mould growth. Thus, of the four basic requirements for Mould growth, moisture is the only Mould growth requirement to control in environments that humans inhabit.

Common household Moulds have a characteristic "musty" or "earthy" smell, and growing colonies of Mould can also be visually observed in many cases. Most people are familiar with Mouldy bread or Mould growth on cheese or other food products that have been kept too long, so the "green fuzzy" characteristic of most Mould growth is familiar. And those who have lived in Florida have heard the expression "green shoe syndrome" which refers to the fact that Mould is particularly fond of leather products left unused for periods of time in dark humid places. In Assam, India, shoes turn green if not used once every 4-5 days!

Although most active Mould colonies appear greenish to black (typical of Mould growing on bathroom tile grout) in color, the characteristics of Mould colonies growing behind vinyl wall covering in buildings takes on   very different characteristics. These Mould outbreaks typically result in pinkish to yellowish staining of the wall covering. They are quite important because they indicate serious, detrimental moisture accumulations within the gypsum wallboard behind the wall covering that cannot be removed by your air conditioning or dehumidification systems. Where these problems appear, they usually require the assistance of a professional (ibid).

Practices That facilitate Mould Growth

The following practices aid in the growth of Moulds inside homes located in hot, humid climates, e.g., Florida. Mould growth on the outside of homes is not covered here.

Air Conditioner Operation: Setting the fan mode switch of your air conditioner thermostat in the ON position. When set to the ON position the blower fan runs continuously and the moisture which has condensed on your air conditioner's (AC) evaporator coil during cooling is re-evaporated and blown back into your home before it can drain off the coil and out of your home. This causes the relative humidity in your home to be significantly greater than if the AC thermostat fan mode switch is set to another position. Even in the "auto" position, some ACs run the blower for 1-3 minutes after the compressor shuts off.

AC Sizing: Oversizing of ACs is common. The more an AC is oversized, the poorer its humidity removal performance, especially at higher thermostat settings. This is because, during each air conditioning on cycle, the moisture removal does not reach full capacity for about the first three minutes of operation. The more the system is oversized, the shorter the on-cycle during which moisture is removed. Thus, if a home is properly sized with a 2-ton AC and a 4-ton system is installed, the 2-ton machine would do a much better job removing moisture even though the 4-ton machine had twice the nameplate humidity removal capability.

Space Pressurization: It is important that homes in hot, humid climates be pressurized slightly with respect to outdoors. The reason is simple. If homes are depressurized with respect to the outdoors, then hot, humid outdoor air will be pulled through the very small air pathways that exist in all building envelopes (walls, ceilings, floors, etc.). To get from the outside of the home to the inside, this air often follows circuitous pathways, e.g., the air may enter the wall system high on the exterior where an outdoor light fixture is mounted and exit the wall system low on the indoors where an electrical outlet is located. If the home has an AC, the gypsum wallboard will be relatively cold — often colder than the dew point temperature of the humid outdoor air that must flow along that gypsum wallboard to that indoor electrical outlet. In Florida, it is not uncommon for summertime outdoor air dew point temperatures to be greater than 80° F! When this occurs, the colder gypsum wallboard condenses the moisture out of the air that is flowing along its rear surface on its way to the electrical outlet that is serving as its pathway into the air conditioned home. As illustrated in the figure below, this can result in moisture accumulation within the wallboard, which, in turn, can result in significant Mould growth.

Shut Interior Doors: Interior doors are kept shut when the AC is on. This results in space pressurization problems in the home (ibid).

Comparison of Wall Systems Moisture Contents

                       

The diagrams in Fig. 9, based on detailed computer simulations that model the combined impacts of heat, moisture and air transport illustrate the importance of this air flow phenomena. The wall on the left bounds a space that is pressurized with respect to the outdoors and the one on the right bounds a space that is depressurized. The 2 Pa (Pascal) pressure gradient is very, very small — there are 101,325 Pa in one atmosphere. Clearly, it is the direction of the pressure gradient rather than its magnitude that is critically important here. You very much want your home slightly overpressurized in hot, humid climates so that dry, cool indoor air is pushed out of the home through the walls (figure on left) rather than have hot, humid outdoor air sucked into the home through the walls (figure on right). Fortunately, it is relatively easy to pressurize a home — all that is necessary is that slightly more air be brought into the home than is exhausted. This normally requires a positive mechanical ventilation system (ibid).

Other items that cause depressurization in homes:

·         Exhaust fans (bathroom, kitchen, attic, crawlspace, etc.)

·         Clothes dryers

·         Supply duct leaks

Sundry items that foster Mould in homes

You can't Mould-proof your home, but you can make it Mould-resistant. Look out for:

·         Leaking Pipes. The worst leaks are those that go undetected because they are hidden out of view, like inside a wall. By the time you discover them, Mould has usually started to grow already.

·         Leaks in the Roof. A roof that leaks into the attic might not be discovered until it's already led to Mould growth. Check the attic regularly for leaks.

·         Wet Clothes. Clothes left in a pile waiting to be washed for more than a day and clothes left wet for over a day after being washed may also foster Mould.

·         Drying your clothes. Drying your clothes in a dryer instead of outside on the line releases a large amount of moisture into your home if the drier is not vented outside the house. Clothes drying inside on indoor clothes lines or racks will also create a buildup of moisture inside unless the room is well ventilated.

·         Damp Basement. Basements often contain higher amounts of moisture or humidity than other rooms because they are usually not well ventilated. Basements are also often colder meaning more condensation occurs which leads to dampness and humidity. Also any water from leaks in your home will often end up running down to the basement since it is lower than all the other rooms. Not only is Mould more likely to grow in basements but because they are usually neglected Mould growth may not be discovered until it is well set in.

·         Flooding. This is a dangerous after effect of a calamity. Your house will be very wet for a long time during a flood, taking days or even weeks to dry out. Since Mould only needs a suitable surface to be wet for 24 hours before it can grow this means there is a huge risk of Mould growth.

Some dangerous toxic Moulds require more extreme conditions than common Moulds do, such as Stachybotrys Chartarum, which requires material to be very wet for several days to grow. Your home is at great risk of being infested with dangerous toxic Moulds (ibid).

·         Water at the house's foundation. Water building up in the yard and ground around the base of your house can cause frequent water problems for the foundation of your home. If the ground around your home slopes towards the house rainwater will end up building up at the foundation. If this causes constant problems you might even need to do some landscaping to modify the slope of the ground so water drains away from the house. Alternatively ditches and drains can be dug to channel water away from the home.

·         Lack of Sensors. Install a digital temperature and relative humidity (RH) sensor and observe your indoor relative humidity. During the hot summer, with the AC on, the RH should not exceed 55 percent during the day on a regular basis. If it does, you probably have problems either with leaks in your duct system or with your air conditioner unit itself – it could be too large, improperly charged or have insufficient air flow across the coil. Consult a qualified AC expert.

The highest relative humidity in your home is likely to occur during mild weather when your AC is not needed during the day. In tropical climate, the outdoor relative humidity reaches very near 100 percent on most nights, regardless of daytime temperatures. If your home is open to the outdoors during these periods, the materials in your home will adsorb moisture from this very humid air, regardless of the temperature (ibid).

If this moisture is not removed during the following day, the moisture of the materials in your home can stay at or above 75 percent for extended periods and Mould is likely to grow on these surfaces. If you have RH levels exceeding 70-75percent for extended periods, and find it difficult to control Mould growth on surfaces in your home in spring, fall and winter, you may need to invest in some type of dehumidification system. Consult a qualified mechanical system expert.

·         Whole-House Ventilation Fans — Opened Windows: Ventilation fans induct moisture when it is humid outdoors, especially if you have noticed Mould growth in your home or you are having trouble controlling the relative humidity in your home. In addition, windows open for long periods when it is humid outside (e.g., during nights and evenings) will create unnecessary bother if you are experiencing Mould growth problems in your home.

·         Vinyl Wall Covering: Impermeable interior surfaces like vinyl wall coverings can result in severe

Mould problems in hot humid climates. Moisture coming from outdoors can accumulate within

the gypsum wallboard behind the vinyl wall covering. This normally occurs as a result of house depressurization where outdoor air is being sucked into the home through the very minute air pathways that exist in all normal wall systems.

As stated, outbreaks of Mould often occur beneath the wall covering on the surface of the gypsum wallboard, normally characterized by pinkish to yellowish "splotches" on the vinyl wall covering. The moisture accumulation also can be severe enough to cause the gypsum wallboard to badly deteriorate and become "mushy." If you have noticed these symptoms, a building science professional should be called in. Positive pressurization of your home is one method of minimizing the potential occurrence of this problem.

·         Return Air Pathways: It is important that there be sufficient air flow pathways for the supply air that is delivered to each room of a home to return to the AC’s air handler unit (the box with the blower fan). Otherwise, the part of the home containing the main return to the air handler unit will be "starved" for air, resulting in depressurization of this space with respect to the outdoors. If this occurs, outdoor air will be drawn through the small pathways that exist in the exterior building envelope. In hot, humid climates, these air flows can result in the accumulation of moisture within the gypsum wallboard, especially if it has vinyl wall covering. This, in turn, can result in the rapid and abundant growth of Moulds —the cellulose (paper) on gypsum wallboard makes an excellent, preferred Mould food.

If room doors are kept open, there will be sufficient return air pathways. However, if rooms doors are closed, the rule-of-thumb is that there should be about 50 square inches of "free" air transfer area for each 100 cubic feet per minute (cfm) of supply air to the room. The term "free" means a simple, clear hole in the wall between the room and the remainder of the home. If, for appearance and privacy reasons, this hole is to be covered by grilles on each side of the wall, then the overall return air pathway area needs to be increased by about 40 percent to account for the air flow resistance of the grilles, or about 70 square inches per 100 cfm of supply air flow.

·         Bathrooms: In most bathrooms, tiles in and around showers and tubs are regularly wet. As a result, most bathrooms grow Mould and require regular cleaning. A weak solution of water and common household bleach can be used to regularly clean these areas and keep them free of Mould. Silent exhaust fans are also recommended to remove excess moisture when somebody is bathing or showering.

·         Exterior Water Management: Redirect water away from the home's exterior — redirect sprinklers so that they don't spray on the walls. Landscape with hills that direct water flow away from the home to forestall Mould.

·         Water Damage: Water damage from major water intrusion in homes should be dried within 24 hours if at all possible. For severe flooding and severe water damage for more than 48 hours, a trained restoration professional should be consulted regarding cleanup procedures.

·         Small Leaks: Even small water leaks will cause Mould problems. Rainwater leaks from improperly flashed windows, wall and roof penetrations and plumbing leaks should be promptly repaired. Periodically inspect under sinks and vanities for signs of water leakage. Use your nose and smell for "musty" or "earthy" odors – they usually indicate the presence of Mould. Fix all water leaks promptly.                                                           

·         Moisture Condensation: Single-pane, metal-frame windows generally condense water on the inside in winter. It is good practice to remove this condensation before it can run off and be absorbed by porous materials like wood casing or gypsum wallboard. Condensation can also occur on other surfaces in homes. If condensation is noticed on interior surfaces in summer, it may indicate a number of problems, including inability to control indoor humidity, AC supply registers aimed directly at interior surfaces, duct leakage problems and pressure imbalances or all of the above. Contact a professional to help diagnose the cause.

·         Closets: Fungi like the dark and closets are rarely supplied with conditioned air as a standard part of AC systems. As a result it is not all that uncommon to have Mould or mildew occur in closets, especially on leather. Leave the closet doors open to provide more conditioned air circulation inside.

·         The Kitchen. One reason why is because there's lots of moisture in the kitchen, e.g., water from running taps, steam from boiling water, fridges and dishwashers, etc. Another reason is there's always plenty of food in the kitchen for Mould to start to grow on.

·         Lack of Ventilation and Stagnant Air. Poor circulation throughout the home sustains dampness or potential moisture, especially in attics, basements, crawlspaces and laundry rooms. Overly “tight” homes designed for energy efficiency can have Mould problems due poor circulation.

Prepare for Melting Snow

Water is always eager to make its way into our living spaces. One crack is enough to cause a serious problem in any indoor environment. As temperatures increase after a snowy winter, homeowners should be aware of vulnerable areas such as rooftops, windows, and other possible ports of entry.

Basements are typically the area of a structure most at risk for water damage because they are located below grade and surrounded by soil. Soil releases water it has absorbed during rain or when snow melts, and the water can end up in the basement through leaks or cracks. Water can even migrate through solid concrete walls via capillary action, which is a phenomenon whereby liquid spontaneously rises in a narrow space, such as a thin tube, or via porous materials. Wet basements can cause problems that include peeling paint, toxic Mould contamination, building rot, foundation collapse, and termite damage. Even interior air quality can be affected if naturally occurring gasses released by the soil are being transmitted into the basement.

Potential Signs of Mould

If you have Mould growing in your house, it will be a gracious visitor and indicate its presence. Some common signs to watch out for are:

Ø  Smelling a Mould Odor

§  When you have Mould growing hidden away in your house, often a Mouldy smell might be the only clue that it's there. Don't ignore Mould odors if you can't see any Mould. You should thoroughly inspect your home before any Mould problems get worse.

Ø  Seeing Signs of Mould Growth

§  Visible Mould growth might seem like an obvious sign of Mould. However many people don't notice small amounts of Mould growth or they think it's just soot or dirt. Sometimes people simply ignore visible Mould in their house. If you can see Mould growth, even if it's only small, you should take action immediately to remove the Mould. Small Mould patches can spread and the fact that there is any Mould shows that the conditions in your home are right for Mould to grow. If you don't take care of Mould it will soon become a bigger problem. Visible Mould growth could also be a sign that there is a much larger Mould colony growing hidden away from view.

Ø  Signs of Water Problems

§  If you have had any long term moisture problems in your house it's usually inevitable they will lead to Mould beginning to grow. So if you know you've had some water problems in your home then it's a pretty good sign you could have Mould. Some signs that you have a moisture problem include water stains or discoloration on walls, floors or ceilings in your house. Seeing these could be a clue that there is Mould growing within or behind the material.

§  Another sign of a moisture problem is surface abnormalities like peeling, bubbling or cracking of the paint or wallpaper. If your walls are bowed, bulging or warped it probably means moisture has got into them. Yet another clue is the surface of walls or other materials feeling damp.

Ø  Water Leaks

§  The above signs of water problems in homes are usually created by leaks. If you already know that you have had a water leak (such as leaking pipes or a leaking ceiling) then just that knowledge by itself, even if you don't see signs of water damage, is a good sign that you might have Mould growing in your house around the area where the leak was.                                   

§  Mould growth from leaks can often be hidden. If the leak was behind a wall or other surface then any Mould will probably be hidden behind the surface too. Even if the leak was not behind a surface there could still be Mould hidden out of view behind a wall or other surface from water which seeped through.    

§  On the exterior of the house there are areas that appear to be “wet” or do not dry out for days after rainy weather. There could be some water in the walls or cavities that are holding water indicating a leak and nowhere for the water to escape.    

Ø  Past Flooding

§  If your house has been flooded in the past then it's likely that Mould would've started to grow. Any Mould would probably be growing in places where flood water remained the longest such as in the basement. Floods can often create Mould growing out of view behind walls or under floors.

Ø  Condensation

§  If you see a lot of condensation in your home then it's a sign that you have a high amount of moisture and hence a sign that you could have a Mould problem. Condensation will occur on surfaces such as glass windows or metal pipes. Mould could be growing where the condensation builds up and collects. Rusting indoor pipes are a sign that you could have a lot of condensation in your house.

§  Besides the fact that condensation creates a buildup of moisture for Mould to grow on, condensation can also be a sign that you have a humidity problem in your home. A high humidity level can feed Mould, another sign that you might have a potential Mould problem.

Ø  Paint

§  When there is a lot of moisture, paint may start to come off surfaces. Paint, or wallpaper, may be peeling, cracked, bulging or bubbling, if moisture is building up behind it.

Ø  Rust

§  Rust in the home is a sign of a moisture problem. You might see rust on nails or metal pipes, meaning you have high humidity, condensation, a water leak, or some other water problem.

Ø  Warping

§  When moisture gets into wood, drywall and other materials it can cause bowing. If you see warped walls, or other surfaces, you probably have a moisture problem.

Ø  Deterioration

§  Water problems can deteriorate materials in your home. Seeing building materials which have deteriorated from moisture can be another sign of Mould.

§  Blocked Gutters

§  When it rains, you may see water building up on the ground near your house. This is usually caused by blocked gutters, or ground sloping towards your house.

§  It can be a sign of indoor moisture problems, because the water can seep into the walls or the foundation. Blocked gutters can also cause water to run down into the roof, or down the walls.

Ø  Allergy Symptoms, Headaches or Memory Problems

§  Sneezing, runny nose, red eyes - if you just can’t seem to kick the allergy symptoms no matter what the season the problem could be inside your home not outdoors. When Mould is growing in your apartment it can cause severe allergic reactions when it’s inhaled or touched. If you’re allergic to Mould serious health concerns like asthma attacks can occur. If you’re allergy symptoms are worse at home than they are outdoors or at other locations then it’s quite possible you have a Mould problem.

§  The biggest cause for concern when it comes to Mould is mycotoxins. These are produced by toxic strains of Mould and can cause serious health problems. Symptoms include dizziness, headaches, short attention span, memory loss and trouble concentrating. This essay will look at toxins in detail later. For the moment, the pecking order is Stachybrotys, Aspergillus,

Acremonium and Alternaria.

§  Lots of House Plants - House plants require consistent watering, which increases moisture levels inside. Bonzai lovers, beware!

Some Moulds that Affect Humans

Acremonium and Alternaria: Both these species, though not considered the most dangerous types of Mould, do give off toxins that cause ill health effects or allergies in people. Acremonium is often found growing very close to the Stachybrotys Mould – the most dangerous type of Mould found so far.

Aspergillus: Studies show this specie of Mould is the second most dangerous Mould type next to Stachybotrys.

Mould spreads quickly. Do remember that Mould spreads – quickly. The best time to take care of a Mould problem is immediately after finding it. The longer remediation is put off, the more will Mould grow – as will the job of removing Mould. If you wait too long it can be impossible to remove all the Mould. Moreover, even if there is just a slight trace of one toxic Mould type, and a large amount of a not so dangerous Mould – each gives off spores and both reproduce at a fast pace. It won’t be long before the area is overrun with toxic Mould looking for a new area to permeate.

Who is Most At Risk?

Certain individuals are more at risk for developing complications when exposed to dangerous household Mould. If you fall into one of these groups you need to be aware of your risk:

Ø  People with allergies:

·         Although this seems obvious, it’s important to consider how they are exposed to Mould. People with allergies to dust will realize that Mould may trigger an attack. However, what if you aren’t allergic to dust, are you safe around Mould? Surprisingly, no. Many people are allergic to Mould that is ingested instead of inhaled. This means that for a person without a dust allergy they can have a serious reaction if they eat something containing Mould. Foods such as mushrooms, dried fruits and soy sauce can cause this reaction.

Ø  People with compromised immune systems:

·         Our immune systems work to ward off illness and allergies. If a person has been through chemotherapy, is living with HIV or has an inherited autoimmune disease, they are more likely to react to being exposed to Mould. Mould is a very strong allergen and for someone without their immune system to protect them, they can quickly develop complications.

Ø  People with lung disease:

·         Just as a person with a compromised immune system may be more prone to complications caused by Mould, the same is true of those with an underlying lung problem. Mould, when breathed in, can become lodged within the lungs. For someone with a lung condition, this can lead to a worsening of their symptoms or in some cases infection.

ALL ABOUT MOULD-1

ALL ABOUT MOULD: PART 1

Mould is a fungus that grows in the form of multicellular filaments called hyphae. Moulds are part of the natural environment, actually part of the fungi fief−which makes it neither plant nor animal, but something in between. Outdoors, Moulds play a vital part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, Mould growth should be avoided. This can be achieved by ensuring that indoor air is healthy.

The World Health Organization (WHO) stresses that healthy indoor air is a basic right. People spend a large part of their time each day indoors: in homes, offices, schools, health care facilities, or other private or public buildings. The quality of the air they breathe in those buildings is an important determinant of their health and well-being. The inadequate control of indoor air quality, therefore, creates a considerable health burden. Indoor air pollution – e.g., from dampness and Mould and other agents – is a major cause of morbidity and mortality worldwide.   

There is clinical evidence that exposure to Mould and other dampness-related microbes increases the risks of rare medical conditions. Toxicological evidence obtained in vivo and in vitro supports these findings, showing the occurrence of diverse inflammatory and toxic responses after exposure to microorganisms isolated from damp buildings, including their spores, metabolites and components.

The prevalence of indoor dampness varies widely within and among countries, continents and climate zones. It is estimated to affect 10–50% of indoor environments in Europe, North America, Australia, India and Japan. In certain settings, such as river valleys and coastal areas, the conditions of dampness are substantially more severe than the national averages for such conditions.

The amount of water on or in materials is the most important trigger of the growth of microorganisms, including fungi, actinomycetes and other bacteria. As the relations between dampness, microbial exposure and health effects cannot be quantified precisely, no quantitative health-based guideline values or thresholds can be recommended for acceptable levels of contamination with microorganisms. Instead, it is recommended in the main that dampness and Mould-related problems be prevented.

Knowledge of indoor air quality, its health significance and the factors that cause poor quality are key to enabling action by relevant stakeholders – including building owners, developers, users and occupants – to maintain clean indoor air. Many of these actions are beyond the power of the individual building user.

Well-designed, well-constructed, well-maintained building envelopes are critical to the prevention and control of excess moisture and microbial growth, as they prevent thermal bridges and the entry of liquid or vapor-phase water. Management of moisture requires proper control of temperatures and ventilation to avoid excess humidity, condensation on surfaces and excess moisture in materials. Ventilation should be distributed effectively throughout spaces, and stagnant air zones avoided.

Fungi are heterotrophic, i.e., they do not produce their own food like plants do. They must get their food from their environment. They get their food by secreting digestive enzymes to dissolve organic and inorganic food materials. They then absorb the soluble products from digestion. In nature, Mould helps decompose or break-down leaves, wood and other plant debris. Moulds become a problem when they go where they are not wanted and digest materials, such as fixtures in our homes.

Fungi are coenocytic organisms composed of masses of tubes or filaments, called hyphae. A coenocyte is a cell or organism with many nuclei which are not separated by cell walls. Moulds are a large and taxonomically diverse number of fungal species where the growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism. The hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls (septa) may delimit connected compartments along the hyphae, each containing one or multiple, genetically identical nuclei. The dusty texture of many Moulds is caused by profuse production of asexual spores (conidia) formed by differentiation at the ends of hyphae. The mode of formation and shape of these spores is used to classify Moulds. Many of these spores are colored, making the fungus much more obvious to the human eye at this stage in its life-cycle.

Mouldy Tomatoes

Moulds are considered to be microbes and can be found in the ranks of Zygomycota (zygote fungi) and Ascomycota (sac fungi). In the past, most Moulds were classified within the Deuteromycota, i.e., imperfect fungi which do not fit into the commonly established taxonomic classifications of fungi based on biological species. Apart from desired biodegradation of natural materials, Moulds also play important roles in biotechnology and food science in the production of various foods, beverages, antibiotics, pharmaceuticals and enzymes. Some diseases of animals and humans can be caused by certain Moulds: disease may result from allergic sensitivity to Mould spores, from growth of pathogenic Moulds within the body, or from the effects of ingested or inhaled toxic compounds (mycotoxins) produced by Moulds (ibid). They can thus be allergenic, pathogenic or toxigenic.

Biology

There are thousands of known species of Moulds which include opportunistic pathogens, saprotrophs, aquatic species and thermophiles. Like all fungi, Moulds derive energy not through photosynthesis but from the organic matter in which they live. Moulds secrete hydrolytic enzymes, mainly from the hyphal tips. These enzymes degrade complex biopolymers such as starch, cellulose and lignin into simpler substances which can be absorbed by the hyphae. In this way Moulds play a major role in causing decomposition of organic material, enabling the recycling of nutrients throughout ecosystems. Many Moulds also secrete mycotoxins which, together with hydrolytic enzymes, inhibit the growth of competing microorganisms.

Moulds reproduce through small spores, which may contain a single nucleus or be multinucleate. Mould spores can be asexual (the products of mitosis) or sexual (the products of meiosis); many species can produce both types. Mould spores may remain airborne indefinitely, may cling to clothing or fur or may be able to survive extremes of temperature and pressure.

Although Moulds grow on dead organic matter everywhere in nature, their presence is visible to the unaided eye only when Mould colonies grow. A Mould colony does not consist of discrete organisms but of an interconnected network of hyphae called a mycelium. Nutrients and in some cases organelles may be transported throughout the mycelium. In artificial environments such as buildings, humidity and temperature are often stable enough to foster the growth of Mould colonies, commonly seen as a downy or furry coating growing on food or other surfaces.

Few Moulds can begin growing at 4 °C (39 °F), the temperature within a typical refrigerator, or less. When conditions do not enable growth to take place, Moulds may remain alive in a dormant state depending on the species, within a large range of temperatures before they die. The many different Mould species vary enormously in their tolerance to temperature and humidity extremes. Certain Moulds can survive harsh conditions such as the snow-covered soils of Antarctica, refrigeration, highly acidic solvents, anti-bacterial soap and even petroleum products such as jet fuel.

Xerophilic Moulds use the humidity in the air as their only water source as their water requirement is very low; other Moulds need more to far more moisture (ibid).

Mould and Decay: Seeing strange colored spots on wooden objects in your house can be disconcerting. Therefore, differentiating between Mould and decay is very important − Mould fungi simply discolor wood, whereas decay fungi actually weaken the wood structure.

Mould on wood

Decaying wood

 Several features distinguish Mould growth from decay. Mould often appears as black, green or brown fuzzy or powder patches. Spores can also be gray, purple or red. Mould growth can easily be brushed, planed or washed off, and the wood beneath the discoloration is most often sound.

Decay may appear as unnatural brown or bleached areas in early stages of fungal infection, and it can be difficult to recognize. Brown-rot, the most destructive type of decay fungi, is characterized by darkening and shrinking of wood, with eventual crumbling in the advanced stage. White-rot, another common family of decay fungi, may cause wood to lose its color or appear bleached. The wood will not shrink or crack but will feel spongy in the advanced stage.

Positive Physiological Effects

Food Production− Some Moulds are essential for food production, particularly in the Orient. A.sojae is used to ferment a soybean and wheat mixture to make soybean paste and soy sauce. Koji Moulds break down the starch in rice, barley, sweet potatoes, etc., a process called saccharification, in the production of sake, shōchū and other distilled spirits. Koji Moulds are used in preparing Katsuobushi.

Red rice yeast (Fungi that can adopt a single celled growth habit are called yeasts) is a product of the Mould Monascus purpureus grown on rice, and is common in Asian diets. The yeast contains several compounds collectively known as monacolins, which are known to inhibit cholesterol synthesis. A study has shown that red rice yeast used as a dietary supplement, combined with fish oil and healthy lifestyle changes, may help reduce "bad" cholesterol as effectively as certain commercial statin drugs.

Some sausages, such as salami, incorporate starter cultures of Moulds to improve flavor and reduce bacterial spoilage during curing.  Penicillium nalgiovense, for example, may appear as a powdery white coating on some varieties of dry-cured sausage. Other Moulds that have been used in food production include:

·         Fusarium venenatum – quorn

·         Geotrichum candidum – cheese

·         Penicillium spp. – various cheeses including Brie and Blue cheese

·         Rhizomucor miehei – microbial rennet for making vegetarian and other cheeses

Pharmaceuticals: Apart from antibiotic penicillin, several statin cholesterol-lowering drugs are derived from Moulds, as is the immunosuppressant drug cyclosporine, used to suppress the rejection of transplanted organs. 

Negative Physiological Effects

Health − Mould spores are common in household and workplace dust; however, when present in large quantities, they can present a health hazard to humans, potentially causing allergic reactions and respiratory problems. This topic will be elucidated later.

Moulds, Mycotoxins and More

The five most common types of Mould in households are Alternaria, Aspergillus, Cladosporium, Penicillium and Stachybotrys and will feature repeatedly in this essay.

2.  Aspergillus. Aspergillus is usually found in warm, extremely damp climates, and in house dust. This Mould produces mycotoxins which is toxic, causing lung infections like aspergillosis. The majority of cases occur in people with underlying illnesses such as tuberculosis or chronic  obstructive pulmonary disease (COPD), but with otherwise healthy immune systems.

3. Cladosporium. Cladosporium is a very common outdoor fungus that can find its way indoors and grow on textiles, wood and other damp, porous materials. This Mould triggers hay fever and asthma symptoms.                                       

4. Penicillium. Penicillium is a very common species found on wallpaper, decaying fabrics, carpet, and fiberglass duct insulation. It is known for causing allergies and asthma. Some species produce mycotoxins, one being the common antibiotic penicillin.

5. Stachybotrys. Stachybotrys chartarum (also known as Stachybotrys atra) is an extremely toxic “black Mould” which produces mycotoxins that can cause serious breathing difficulties and bleeding of the lungs. This Mould can be found on wood or paper.

Mould, Bacteria and Mycotoxins: Many health effects are caused by exposure to the interior environment of Water Damaged Buildings (WDB). The complex mixture of contaminants present in the air and in the dust in WDB form a toxic chemical stew. There are so many possible sources of these toxic compounds found in WDB that can lead to the variety of symptoms caused by Mould illness, no single compound can be identified as the sole cause of the inflammatory responses or the illness seen in affected patients. Since no one thing can be deemed as solely responsible for the sickness, the sole cause becomes the WDB itself.

A list of some of these dangerous compounds and an explanation of each follows infra. Please note that this toxic chemical stew is a very complex mixture that truly wreaks havoc in the body. Patients should understand what is making them sick, so they can avoid exposure in the future.

o   Fungi - A single-celled or multicellular organism. Fungi can be true pathogens that cause infections in healthy persons or they can be opportunistic pathogens that cause infections in immunocompromised persons.

o   Bacteria - Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life).

o   Actinomycetes - A group of gram-positive bacteria (order Actinomycetales) that produce various bioactive agents.

o   Mycobacteria - A large family of bacteria that have unusually waxy cell walls that are resistant to digestion.

o   Mould - Mould refers to multiple types of fungi that grow in filaments and reproduce by forming spores. Mould may grow indoors or outdoors and thrives in damp, warm, and humid environments. Mould can be found in essentially any environment or season.

Spore – A spore is a tiny microorganism produced by Mould that is not visible to the naked eye. Mould spores are very hardy and can survive under conditions in which Mould cannot grow, such as in dry and harsh environments. These spores travel through outdoor and indoor air. When Mould spores land on a surface where moisture is present, Mould can start to grow.

Mycotoxins - toxic chemicals that are present on spores and small fragments of Mould and fungus that are released into the air.

Endotoxins - also called Lipopolysaccharides (LPS), are cell wall components of Gram negative bacteria. They are shed into the environment of WDB upon death of the bacteria. LPS cause inflammatory responses via signaling pathways in the body, releasing inflammatory cytokines. LPS aggravate existing lung disease (asthma, HP), can cause inflammation of the lungs and are synergistic with mycotoxins.

Inflammagens - an irritant that elicits both edema and the cellular response of inflammation (ibid).

Where Do I Begin?

You display symptoms that baffle doctors. You suspect Mould in your home. What next? If the symptoms are severe, consider leaving the environment to see if you feel better. If your symptoms improve, testing your home for Mould is the next logical step. It's important to test your home before cutting into any drywall or lifting any carpet. Disturbing the Mould spores can worsen a situation.

Preliminary testing can be done with a simple moisture meter obtained from a local hardware store.

Place the probes in a suspected wall to see if hidden moisture is present. There are several options for testing. Mould plates found in hardware stores do not "pull" the air and therefore provide only a limited picture of your air; a toxic Mould issue can easily be missed when using this product. Initial testing can include an Environmental Relative Mouldiness Index (ERMI) test, which involves a dust sample. A laboratory will do the necessary testing. The cost associated with Mould testing is often a stumbling block, but it can save you thousands of dollars later. Precautionary testing before buying a home may prevent even greater financial loss.

No Mold growing in a home is good Mold—period. Whether the Mold is white, black, green, maroon, turquoise, gold, or brown, it is still Mold, and at some point it may produce spores or gases known to create adverse health conditions to human beings and pets.

 

Other than a lab test, you can do an air test, which is less optimal than a dust or tape sample. However, when taken in conjunction with dust samples, it can still be a valuable tool. Another option is a combination of carpet dust samples, air samples, and tape lifts done by a hygienist. If you believe litigation will be involved, it is important to hire a hygienist.

Questions to ask before you hire a hygienist:

1.       Do you believe Mould is harmful? The answer must be yes.

2.       What constitutes a "safe" level of Mould? In an air sample, Mould counts should be equal to or below outdoor counts. There should be no stachybotrys. Not one spore. Aspergillus should be present only at negligible levels. The standard in Belgium requires no more than 2.5 percent aspergillus in the total count. In the USA, there is no official standard for acceptable Mould spore levels. “Clean” residential buildings are typically 230/m3 + 630/-230. Buildings with evidence of flooding are typically much higher: 2200/m3 and Mould-damaged buildings are typically extremely high in comparison: 36,000/m3.

3.       Can I see the report? Do not rely on a hygienist's word. It's important to see your counts for yourself, especially when assessing the levels of aspergillus.

Where do you begin medically? You can take the visual contrast sensitivity test or a urine test. It can be difficult to find a physician who understands toxic exposure. The American Academy of Environmental Medicine has a list of doctors who may be familiar with toxic Mould.

If you have a primary doctor willing to consider Mould exposure as a cause of illness, ask for specific lab work such as c4a, vascular endothelial growth factor, melanocyte-stimulating hormones (melanotropins or intermedins) and leptin. Or ask for the full set of lab tests. Alternative health care offers a wide range of diagnostic and detox options, as well.

The Mould journey is a daunting one, but knowledge is power. It is better to deal with Mould than ignore it. Some stories are extreme. Some have a happier ending, where Mould was suspected, testing was done, and remediation was performed successfully. No one got sick, because the Mould was dealt with quickly and thoroughly. In some cases Mould was suspected, testing was done, and nothing harmful was found (ibid).

If there was/is Mould in your house, before launching an all-out attack against them, consider the Four Factors of Mould.

1.       The Fungal Biomass: This is the Mould you see. Mould comes in every color, texture, and style imaginable. A Mould Test Kit is the only sure way to know what kind of Mould is growing. The color

and appearance can be difficult to differentiate because of the variety of Moulds. When the media use the terms “Black Mould” or “Toxic Mould,” they are usually referring to Stachbotrys. Both media terms are misleading, because many Moulds are black and many Moulds produce toxins. Further, Stachbotrys is not always black, but is sometime green, gray, or brown, depending upon its food source.

                                                                                                                                                                                                                                                                                            

Ø  Stachybotrys can produce extremely toxic mycotoxins, suspected carcinogens and immuno-suppressive. Exposure to these mycotoxins occurs through inhalation, ingestion, and dermal exposure. Long term exposure has shown that Stachybotrys and Chaetomium can destroy the myelin sheath, leading to autoimmune disease. These are the only two fungi that can also be linked to Multiple Chemical Sensitivity.

Ø  Penicillium fungi are commonly found in soil, food, cellulose, grains, paint, carpet, wallpaper, interior fiberglass duct insulation, and decaying vegetation. This fungi has been linked to common illnesses such as ear infections, pneumonia, and urinary tract infections. Penicillium infections are most commonly exhibited in immunosuppressed individuals. An indication of infection is the appearance of papules that resemble acne on the face, trunk, and extremities.

Ø  Fusarium is a common soil fungus and inhabitant on a wide array of plants. This fungi is often found in humidifiers, water-damaged carpets and a variety of other building materials. Human exposure may occur through ingestion of contaminated grains and possibly through the inhalation of spores. Fusarium are frequently involved with eye, skin, and nail infections.

Ø  Cladosporium is pigmented dark green to black in the front and black on the reverse with a velvety to powdery texture. One of the most commonly isolated from indoor and outdoor air, Cladosporium is found on decaying plants, woody plants, food, straw, soil, paint, textiles, and the surface of fiberglass duct liner in the interior of supply ducts. These fungi cause skin lesions, keratitis, nail fungus, sinusitis, asthma, and pulmonary infections. More commonly, it is a more causative factor for intrinsic asthma.

2.       The Odor / Volatile Organic Compounds:

Volatile Organic Compounds or VOCs are organic chemical compounds that have high enough

vapor pressures enter the atmosphere. This means they are in the air we breathe. VOCs are a  byproduct of Mould growth. When Mould digests organic matter, such as drywall, it releases VOCs into your home. When the Mould blooms and releases spores into the air, those particles can also contribute to the Mouldy smell. In short, if you can smell a mildewy or Mouldy odor, there is Mould contaminating your air.

3.       Mycotoxins:

Ø  The dangerous by-product of Mould, the thing that makes you sick, is called a mycotoxin. A Mycotoxin is a toxin produced by mushrooms, Moulds, and yeasts. Where there is more fungal growth, there are higher mycotoxin levels. Toxins vary greatly in their severity. Some fungi produce severe toxins only under specific conditions, while some are lethal, some weaken the immune system without producing symptoms specific to that toxin, some act as allergens or irritants, and some have no known effect on humans. This topic will be dealt with at length later.

Ø  Mycotoxins may cause a variety of short-term as well as long-term adverse health effects. These range from an immediate toxic response and immune-suppression to potential long-term carcinogenic effects. Symptoms include dermatitis, recurring cold and flu-like symptoms, burning sore throat, headaches and excessive fatigue, diarrhea, and impaired or altered immune function. The ability of the body to fight off infectious diseases may be weakened resulting in opportunistic infections. Because these symptoms may also be caused by many other diseases, misdiagnoses of mycotoxin exposures are common. Occupational or building-related exposures to mycotoxins through inhalation are slowly being recognized as a major indoor air quality problem. Generally, removal of causative agents, the Mould and mildew, is necessary.

4.       Spores:

Ø  Mould spreads by creating reproductive cells called spores and sending them into the environment. They are all around us and you cannot avoid being exposed to them.

Ø  Mould spores attach to people’s skin, clothing, shoes, shopping bags and belongings. Other ways spores can enter your home invisibly are: through open doors and windows, through your home’s heating, ventilation and air conditioning system, or on anything that comes from outside.

Ø  Once spores enter, they can settle onto carpeting or other surfaces inside your home. You cannot keep spores out of your home, but regular home cleaning and maintenance often can prevent Mould problems before they arise. When Mould spores enter your home, they need moisture to begin growing, digesting and destroying. Mould can grow on almost any surface, including; wood, ceiling tiles, wallpaper, paints, carpet, sheet rock, and insulation. Mould grows best when there is a lot of moisture from a leaky tap, humidity, or flood. There is no way to rid your home of all Moulds and Mould spores. You can control Mould growth by keeping your home dry.

Mold is an opportunistic pathogen, which means it will take advantage of any conditions favoring its growth. Its spores can travel to neighboring rooms, land there, and not grow at all. They can sit there dormant for months or even years. Then one day the right combination of temperature and humidity will activate them, allowing them to germinate and start growing. That's why, during the remediation process, proper containment is a must to prevent cross-contamination.

 

   

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[1] Taxonomy is the science of naming, describing and classifying organisms and includes all plants, animals and microorganisms of the world.

RADIAL TIRES

RADIAL TIRES

Advantages of a Radial Tire

A radial tire (actually, a radial-ply tire) is a particular design of vehicular tire. In this design, the cord plies are arranged at 90° to the direction of travel, or radially (from the center of the tire).

All tires are reinforced with a series of cord plies, which accords a tire flexibility and strength. This network of cords that gives the tire its strength and shape is called the carcass. All common tires have a carcass of cords of polyester, steel, or other textile materials, inlaid with several layers of rubber, a practice started over 50 years ago.

Earlier, the fabric was built up on a flat steel drum, with the cords at angles of about + 60° and −60° from the direction of travel, criss-crossing over each other. They were called cross-ply or bias ply tires. Radial tires lay all of the cord plies at 90 degrees to the direction of travel (that is, across the tire from lip to lip). This design prevents plies rubbing against each other as the tire flexes, reducing the tire's rolling friction, allowing vehicles with radial tires to achieve better fuel economy than with bias-ply tires.

With only radial cords, a radial tire would not be sufficiently rigid on contact with the ground. The entire tire is further stiffened by additional surrounding belts oriented closer to the direction of travel, but usually at some "spiral" angle. These belts can be made of steel, polyester, or Aramid fibers such as Twaron or Kevlar. 

Radial tires separate the tire carcass into two separate systems and provide advantages like:

·         The radial cords in the sidewall allow it to act like a spring, giving flexibility and ride comfort.

·         The rigid steel belts reinforce the tread region, giving high mileage and performance.

·         The tire absorbs shocks, impact and bumps.  The result is better ride and operator comfort.

·         Greater productivity. More of your machines power is actually used.

·         Reduction in tire replacement, given the longer service life of radial tires.

·         Less ground contact and damage.

·         Excellent cost benefit ratio, i.e., more cost-effective.