Mold – The Hidden Threat

“Mold is not a problem in our apartments.  It’s not a problem in Shanghai.” This was the response of my apartment complex building supervisor when I asked about what he knew about mold.  When I pressed further and asked who he could refer me to for mold problems, he shrugged and answered, “We don’t know anyone.”  Sound familiar?  There is little awareness of mold as a health hazard in China and therefore it is difficult to find specialists to test for it or advise on how to remove it.  Yet, consider:

  • The World Health Organization (WHO) recently released guidelines on indoor air quality in which mold was addressed as one of the three highest risk areas to public health
  • Indoor air pollution from biological agents in indoor air related to damp and mould increases the risk of respiratory disease in children and adults by 50%[1]
  • The EPA has listed mold as one of the key triggers leading to asthma attacks (~20% of asthma prevalence)[2]

Household Mold Threats in China

What is it?

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 or break-down leaves, wood and other plant debris.  Molds become a problem when they go where they are not wanted and digest materials such as our homes.  In some cases, however, mold may not be visible but may have a musty odor. If allowed to grow, mold can contribute to poor indoor air quality.

Mold requires three things to grow:

  • Oxygen
  • Moisture
  • Food material (can be just about anything – leather, fabric, paint, wood)

Washing, cooking, air humidifiers, unvented clothes dryers, condensation and leaks from the outside all produce the kind of indoor moisture that mould needs to grow. Also, poor ventilation contributes to higher humidity levels and leads to condensation, which also allows mold to grow.

Why is this a problem in China?

Despite common belief, mold does in fact grow in China!  As long as oxygen, moisture, and a food source are available, mold will take root.  Many foreigners are accustomed to looking for mold in walls, under carpets, and in basements.  However, these are not the usual suspects in China, where the construction material of choice is cement, bare floors are common, and few people deal with a basement.  Yet, the prevalence of humidifiers, the tightly sealed construction of new apartments, and poor ventilation mean that mold still is very much alive.  The largest part of the problem is that the low attention to mold issues and incorrect remediation results in a higher degree of unwitting exposure.

Contact Us to check household mold in China

What is the health impact?

In order to reproduce or when disturbed, molds release small “spores” into the air and these spores are small enough that people can actually breathe them in.  Our reaction to the spores is what causes illness.  Mold has a probable link to a wide variety of symptoms, depending on species type and each individual’s personal reaction.  Common symptoms may include:

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

Although healthy adults may not react to mold, WHO research has found that damp and mold increases the risk of respiratory disease in children and adults by 50%[3].  Further, mold combined with dust mites may account for 20% of asthma prevalence[4].  At special risk are those who already have allergy sensitivities or asthma, lung disease, and also those with weakened immune systems such as the elderly, or with leukemia or AIDS.

A small number of molds produce toxins called mycotoxins. When people are exposed to high levels of mold mycotoxins they may suffer toxic effects, including fatigue, nausea, headaches, and irritation to the lungs and eyes.  In some cases, most famously with what was is popularly called, “toxic black mold,” mycotoxins can lead to fatalities.

In addition to the health impact, mold can be very costly for homeowners if not quickly and effectively resolved.

How do I test for it?

We usually only do a mold investigation when a client exhibits symptoms that are associated with mold such as allergies or breathing problems or has visually seen or smelled mold.

Ask yourself these questions:

  • Do you ever find yourself more tired at home than you did before you left work?
  • Do you see more signs of cold or flu symptoms amongst your family?
  • Is there any particular area or room that smells musty or “earthy” even though you keep a clean home?
  • Do you have high moisture in your home from humidifiers, internally vented clothes dryers, frequent showers, little ventilation or lots of plants?
  • Can you see stains or discolorations on floors, walls, window panes, fabrics, carpets and other indoor surfaces?

Mold can also grow unseen.  Since construction in China is largely concrete, fortunately, drywall mold growth is not a major concern.  However, we have seen mold growing behind baseboards, inside of cabinets, and under carpeting.  In one case, we found mold growing inside an air conditioning vent inside a gym, which was blowing spores to all gym users inside the conveniently humid environment!

The goal of mold sampling is to help determine whether the particulates present in the indoor environment are elevated enough to negatively affect or cause allergic symptoms with the individuals that occupy the indoor environment.  If the individuals are experiencing allergic symptoms, you then have to ask whether or not the symptoms are associated with the elevated particulates in the indoor environment of a specific building or room. If symptoms abate a few hours after leaving a building, it is likely associated with the building and the circumstances call for further investigation, especially if the symptoms are severe or are experienced by many people.

If a problem is found, how can I remediate?

The number one thing that you can do to counter the growth of mold is to prevent or reduce the presence of persistent dampness on interior surfaces in your home.  Of the items that mold needs to grow, moisture is the only one that we can really control.  Mold is much easier to prevent than to remove!

  • Stop water leaks, whether from outside or plumbing. Keep water away from concrete slabs and basement walls.
  • Increase ventilation, especially along the inside of exterior walls. Use a fan if there are no windows available
  • Make sure that warm air flows into all areas of the home. Move large objects a few inches away from the inside of exterior walls to increase air circulation.
  • Install and use exhaust fans in bathrooms, kitchens, and laundry rooms.
  • Clean and dry water damaged carpets, clothing, bedding, and upholstered furniture within 24 to 48 hours, or consider removing and replacing damaged furnishings.
  • Vacuum (HEPA filter-equipped machine) and clean your home regularly to remove mold spores.
  • Check around your windows for signs of condensation and water droplets. Wipe them up right away so mold can’t start to grow

Generally, if mold is only found on a non-porous surface smaller than about 1 square meter, you can remove it yourself.  Furniture, large porous materials, or items that cannot be washed should be discarded.  Note: do not paint over mold, as mold will eat the paint.

Source: Washington State Department of Health

We are frequently asked whether landlords are obligated to remove mold.  Unfortunately, we have found that in China, there is no legal requirement for landlords to either inform new tenants of historical mold problems nor to remediate.  Most of our clients have had some success in getting landlords to take action.  The danger, is that many landlords, even well-meaning, worsen the problem by using incorrect clean-up techniques such as:

  • Scrubbing mold, releasing spores everywhere
  • Not sealing the contaminated area, leading to spores entering the HVAC system and circulating through the residence
  • Not providing clean-up workers eye or breathing protection
  • Painting over the mold, which provides mold with even more material to grow

For porous materials or a large area, our typical recommended approach is to use a biocide that is fast-acting, effective against the mold identified, is cost-effective, and perhaps most importantly, does not leave chemical residues (leaves a salt residue only).  We have also recommended the prevention of mold reoccurrence with the application of special coatings.

We recommend you contact us in the following situations:

  • Family member(s) are exhibiting allergic reactions in your home but not elsewhere
  • Have recently had water damage and would like to prevent mold growth
  • Can smell mold odor but cannot locate
  • Have located mold but do not want to remediate yourself
  • Have identified mold but do not trust landlord to remediate

Contact Us about mold mildew in China


[1] WHO statistics: http://www.euro.who.int/en/what-we-do/health-topics/environmental-health/air-quality/facts-and-figures

[2] WHO report citing Melse and de Hollander, 2001.

[3] WHO statistics: http://www.euro.who.int/en/what-we-do/health-topics/environmental-health/air-quality/facts-and-figures

[4] WHO report citing Melse and de Hollander, 2001.