How to Avoid the Mold Horror Story: 12 Ways to Prevent and Treat Mold

It has been a long year in China with health and safety concerns coming to the forefront of international media, but, for many, the summer brings about a holiday and a time to travel or return home. After a great few months abroad, there is nothing worse than returning to your Chinese residence and walking through the front door to have your senses overpowered by a musty, stale smell. After the initial nasal shock, you then reach for the light switch and your fingers graze a fuzzy patch on the wall. You cringe as you flick the switch to discover…Mold.

This is mold season now mainly because of the dampness outdoors and will stay this way for another 3-4 months. PureLiving frequently deals with mold and we have prepared a few tips that come from our own experience with the pesky fungi. This is timely and not limited to any single compound, local or top end.  Mold does not discriminate!

To help you avoid the horror story described above, here is a description of mold and how it affects you, followed by a dozen tips for preventing and treating mold problems.


What is Mold?

Mold is the common word for any fungus that grows on food or damp building materials.  It often looks like a stain and comes in a variety of colors.  In nature, mold helps decompose plant debris, but indoors mold can become a problem.  If allowed to grow, mold has an unpleasant odor and can contribute to poor indoor air quality and impact health.

Mold growth is driven by moisture.  Washing, cooking, air humidifiers, unvented clothes dryers, condensation, leaks from the outside, and poor ventilation all produce the kind of indoor moisture that mold needs to grow.

How Does Mold Affect You?

In order to reproduce or when disturbed, molds release tiny “spores” into the air and these spores are small enough that people can actually breathe them in.  The spores may colonize lungs and actually grow in our bodies causing infection. Spore may also release microbial volatile organic compounds (MVOCs) that have a musty, earthy odor.  Like VOCs released by manmade items and chemicals, MVOCs can cause adverse reactions in people.

Common symptoms include:Mold1

  • Eye, nose and throat irritation
  • Headaches
  • Coughing and phlegm build-up
  • Wheezing and shortness of breath
  • Allergic reactions and triggering of asthma attacks

WHO research has found that damp and mold increases the risk of respiratory disease in children and adults by 50%.  Further, mold combined with dust mites may account for 20% of asthma prevalence.  At special risk are those who already have allergy sensitivities or asthma, lung disease, and also those with weakened immune systems.

A small number of molds produce toxins called mycotoxins which can cause toxic effects, including fatigue, nausea, headaches, and irritation to the lungs and eyes.  Infants have developed bleeding in their lungs. In rare cases, most famously with what is popularly called, “toxic black mold,” mycotoxins has led to fatalities.  In addition to the health impact, mold causes physical damage, spreads quickly, and can be very costly for homeowners if not quickly and effectively resolved.

A Dozen Tips for Dealing with Mold:   Mold Removal

1. Mold needs food, oxygen, the right temperature, and moisture to grow.  Unfortunately, the only thing of these we can control within an inhibited space is moisture.  Therefore, focus on that.  Stop the moisture, you’ll stop the mold.  Don’t stop the moisture, mold will eventually return.

2. Moisture comes from any of three areas: interior moisture (humidity), plumbing within a wall, or water intrusion on the other side of the wall.  We usually find the answer pretty quickly with a moisture meter, but if you don’t have access to one, you can get a good idea with a little investigation.  If (during the winter) you frequently see condensation on the windows, you have a hygrometer that shows relative humidity in excess of 60%, or you frequently take showers or have a lot of plants, chances are it’s interior.  If the wall is against a bathroom, you know there may be piping inside, or there has been water damage, chances are it’s in the wall.  Finally, if the mold is on the inside of an exterior wall (or below a roof), go outside on a wet day after a rain.  If you find standing water, or see gaps in the foundation, or cracks and crumbling mortar/cement, water is coming in from the outside.

3. The ideal relative humidity is less than 55%.  This is determined with a hygrometer or moisture meter, which can be purchased pretty cheaply (contact us if you need one).  Humidty is relative because as temperature goes up, the air can hold more moisture (humidity goes down).  Therefore, colder rooms are more likely to have mold (ie. basements).  Turn on your exhaust fans after taking a shower and leave it on for about 10 min afterwards — this cuts down a lot on interior humidity.

4. Dehumidifiers are probably your best tool against mold if the moisture is from the inside.  Good dehumidifiers can be set on auto and left to turn on when they need to.  Air con does help dehumidify, but only about 5-10%, and uses much more electricity, so is an inefficient dehumidifier.

Watch: Dehumidifier Tutorial Video

5. If you’ve identified the problem to be outside, building management or a contractor can be helpful by sealing that and drying out the cement with a heater (don’t use anything butane or gas fired due to safety) — the little electric ones shaped like a satellite dish are a little safer and can be directed.  The wall needs to be absolutely dry before any painting or replastering.

6. Painting over mold is really bad, though building managers in China love to do it.  You get anywhere from 2 weeks to 2 months of hiding the problem.  Most paint will not kill mold — it simply gives mold more to eat.  There are anti-microbial paints — I like Fluegger wet room paint.  Expensive, but we did some testing and found this was the best.  I’ve never heard of alcohol (I would think this would evaporate quickly) but we also have had success with specialty anti-mold additives — just a small amount goes a long way.  Be careful to check the VOC levels of anti-mold paint, however.  Most trade one evil for another.

7.  Similar to covering up mold problems with paint, wallpaper is bad.  Avoid homes with Mold sporeswallpaper.  The worst is bathrooms with wallpaper.  I have come across wallpaper that when we peeled it back had a fuzzy green slime underneath.  No ventilation + tasty glue paste + moisture barrier = great conditions for mold growth.

8. Bleach is not a good solution to clean.   The best, believe it or not, is a HEPA-filtered vacuum cleaner.  This removes spores, which are easily disturbed during cleaning activities and are what causes us to have allergenic reactions.  The HEPA vacuum removes spores and traps them in a filter.   Why is bleach not a good idea?

* Bleach whitens the top of mold structure but doesn’t kill the underlying roots (hyphae).  Bleach itself is 99% water, so you end up leaving water which gives the mold more to grow
* Most of us are using the bleach on dirty nasty areas.  Bleach is deactivated when it contacts organic material so should only be used on already clean areas
* Bleach is very destructive and destroys fabric, concrete, skin, etc.  It also is not healthy to use and some people can have a negative reactions to the gas produced

9.  Better solutions — tea tree oil, borax, Sporicide, or chlorine dioxide (although shares a common part of its name, it is quite different than chlorine bleach).  Some people like vinegar, but I find this not very useful, fresh smelling, and it tends to crumble concrete.

10.  If you can’t dehumidify in a small space (like a closet), chlorine dioxide sachets are a great solution.  They are packets of a chemical powder called Aseptrol that releases non-toxic chlorine dioxide gas when humidity rises.  This is a very effective fungicide and libraries use this in their archives to keep books from getting moldy.  Boat owners also use these when they store their boats in dock.  We’ve had very good success using these and they last several months.

11.  If you have a mold problem (see mold, smell it, or have allergenic symptoms), bring an air filter into the room and keep it on high 24/7.  You are sick because of spores being expelled by the fungi and the smell is from mold VOCs (volatile organic compounds) — a chemical emitted.  Carbon filters will help reduce the smell and the HEPA filters will help remove the spores that make you sick.  This is not a long-term fix, but will at least treat the symptoms while you work on fixing the source.

12. If you are not sure if it is mold (smell it or have symptoms but can’t see spores), you can test.  Testing consists of taking a sample of air and then examining it in a specialized lab to identify the severity of spores and the type.  This can be compared against a “clean” reference room and the outdoors to determine how much effort you might need to put in proportionately into remediation.

Well, that ended up being a few more than a few. There’s a lot of info out on the Internet, but these are all based on actual experience and observation, so hope that helps.

Contact us for more information or to have your home tested today! 

Shanghai phone: +86-(21)-3469-2269
Beijing phone: +86-(10)-8595-0318


Service available in English or Chinese

Contact Us

For more information on Mold, see some of our other blog posts:
More on Mold
Mold Success Story
Mold Testing and Solutions done easy
Mold, China’s Little Secret




This entry was posted in "How to" and Tips. Bookmark the permalink.

How to Avoid the Mold Horror Story: 12 Ways to Prevent and Treat Mold

  1. Molds are part of the natural environment. In outdoors, molds play an important part in nature by breaking down dead organic matter such as fallen leaves and dead trees, etc. But indoors, mold growth should be avoided and prevented. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye (only on microscope) and float through outdoor and indoor air and contaminate areas. Mold may begin to grow indoors when mold spores land on surfaces that are wet or areas with moisture. There are many types of mold, and none of them will grow without water or moisture. So, moisture plays a great part of it.
    They attack usually on foods but they also attack non-food items like leather, wood and porcelain. Do you notice your allergic reactions are worse when you’re at home but you feel better when you go out? Well, expect it. If so then it’s especially likely you could have mold. Don’t go weary of staying in one place. Find a way for mold detection

  2. If you’re in doubt of any unpleasant growth in your house, you should simply assume there is a problem whenever you see mold or smell mold odors. Testing should never take the place of visual inspection (which is recommended) and it should never use up resources that are needed to correct moisture problems and remove visible growth.
    People used to think that molds were harmless but it isn’t. The fact is, some molds produce a toxin called aflatoxin (toxic and among the most carcinogenic substances known) that causes illness and death in people.
    Sometimes, mold growth is hidden and difficult or hard to locate and find. In such cases, carefully conducted sampling and visual inspection may help determine the location of contamination. However, mold testing is rarely useful for trying to answer questions or inquiries about health concerns. For more information, see mold testing services


Your email address will not be published.

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>