1. University of Tartu
Department of Public Health
Molds and Excessive Humidity in the Living Environment
Essay in Environmental and Occupational Health
Author: Ashwath Venkatasubramanian
3rd Course, Group 10
Tartu 2015

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TABLE OF CONTENTS
Introduction.............................................................................................................................3
Effect of mold on health......................................................................................................3-4
Detecting exposure to molds...............................................................................................4-5
Reducing exposure to molds...............................................................................................5-6
Summary.................................................................................................................................6
References.............................................................................Error! Bookmark not defined.

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Introduction
Molds in the living environment can have serious health effects on humans. Molds in
the living environment have often been overlooked in the etiology of some diseases and
conditions. Due to this, new research is uncovering the true effects of mold in our living
environment. Molds are a group of fungi that grow in the form of multicellular filaments. This
group of fungi is very large. In fact, it is estimated that there are anywhere from 10,000 to
300,000 species of molds and we are far from discovering all of them. Molds are nature’s
recyclers. They cause biodegradation of natural materials, allowing for nutrients and energy to
be freed up for other plants. Molds can grow on any surface in the right conditions, some of
which are humidity and warmth. Therefore, in the living environment, molds can be found on
food, in the water and even in the walls and ceilings of the environment that one lives in/works
in. In most instances, molds are not dangerous and the consumption of some molds are even
beneficial. However, certain species of molds and molds in large amounts can cause health
problems such as asthma, serious allergic reactions or intestinal toxicity. The aim of this essay,
is to explore the deteriorating effects of mold on the human health and to overview the methods
of detection and prevention. This essay focuses predominantly on mold associated with indoor
air quality as opposed to mold on food and in water.
The effects of molds on health have not been widely studied, however, molds and poor
air quality have been clinically associated with immunological reactions and respiratory
problems. Molds produce mycotoxins as a metabolic byproduct and, as its name suggests, can
be toxic to humans and animals, even in small amounts. While it is known that outdoor air
quality can have adverse health effects on humans and animals, the evidence that they play a
role in health problems related to indoor air is extremely weak. Nonetheless, one group of
mycotoxins, trichothecenes produced by S. chartarum, has received a lot of attention. In a

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report from the Centers for Disease Control and Prevention1, indoor exposure to these
mycotoxins was suggested to be associated with acute pulmonary hemorrhage in of 10 children
at the Cleveland Children’s Hospital. The mold T. cutaneum has been shown in a 10 year
surveystudy in Japan to have anassociation with hypersensitivity pneumonitis, which is caused
by a granulomatous lymphocytic inflammation in the alveoli. The Japanese survey was
conducted of all cases of this condition throughout the country. The survey showed that cases
occurred mainly among housewives, who therefore spent most of their time in and around a
building2. This sets an example of a group, particularly at risk of developing infection or
condition due to indoor mold. Similarly, another risk group are immunocompromised
individuals, such as HIV+ patients. Opportunistic molds in the environment can result in
infectionof the patient. An example is Aspergillus, giving rise to infections also inpatients with
less severe airway disease, such as cystic fibrosis, asthma and chronic obstructive pulmonary
disease. People who are atopic sometimes get a severe infection in which aspergillosis causes
an allergic reaction giving the person wheezing, pulmonary infiltration and finally fibrosis3.
Allergies or allergy-like symptoms can be caused by mold, induced by dampness. The most
prevalent fungi associated with mold allergy are Aspergillus, Cladosporium and Penicillium.
Sensitization of certain fungi can lead to hypersensitivity reactions. Some fungal species can
bring about histamine release by other mechanisms therefore causing allergy-like in
non-sensitized people.
The first step in preventing mold buildup indoors is to carryout anexposure assessment.
Since dampness is heavily correlated with mold production, questionnaires asking about
previous leaks, flooding, wet basements, window condensation, visible fungal growthor moldy
odors are used. The extent of water damage and damp is also assessed. The questionnaires are
usually followed up with measurements of humidity in the air and moisture content of the
building materials. Humidity level over 50% can result in increased mold and dust mite

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production. In addition to measuring dampness, there are also methods to directly measure the
amount of microorganisms in the air of the environment. This can be divided into two
categories: Non-culture and culture methods. The culture-based method is based on the method
of collecting air samples or settled-dust samples. The sampling of the microorganisms is carried
out by impaction (deposition of the microorganism from the air onto a solid or semi-solid
surface), liquid impingement (using inertia to collect microorganisms into a liquid medium), or
air filtration (collection of microorganisms from the airstream via the use of a filter). After the
sample has been collected, they are cultured on culture media and incubated at a specific
temperature for 3-7 days. Finally, after the culture period, the colonies of fungi are counted
manually or image-analysis techniques are used to determine whether there is a significant
amount of microorganisms in the air. In the non-culture based methods, the sample is collected
via air filtration or liquid impingement and stained to be viewed under an electron or scanning
microscope. Additionally, the monitoring of the conditions should be carried out relatively
frequently, especially in areas with large climatic fluctuations due to seasons. However, this
might not be feasible and so the sampling should be done during the times at which individuals
are greatest at risk (e.g. monsoon season).
The two main ways to improve the living environment to eliminate predisposing factors
of mold production is to increase the ventilation and remove/subdue the sources of humidity.
Increasing ventilation, results in the dilution of pollutants, allergens, toxins in the air.
Therefore, by reducing the concentration of the pollutants, the risk of developing a condition is
reduced as well. There are three main types of ventilation: Natural, mechanical and hybrid.
However, the best out of the 3 would be either mechanical or hybrid, due to practicality and
reliability. The only con of the two aforementioned types of ventilation is cost and electricity
usage. The reduction of humidity also plays a big role in reducing mold production. A simple
dehumidifier or air conditioner can do this by ventilating and controlling the humidity of the air

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in the closed environment. Furthermore, the sources of humidity canalso be controlled. Sources
can be natural, such as rainwater or groundwater leaking into the enclosure and infiltration of
warm or humid air from the outside. On the other hand, sources of humidity can also be
anthropogenic. Examples include sewer pipe leakages, cooking with steam and the simple fact
that humans breathe out humid and warm air. These factors must be taken into account when
new buildings are built. The buildings should be constructed with utmost care and good quality
materials, as to prevent too much dampness. Furthermore, a good mechanical ventilation
system should be in place to dilute the pollutants and manage the humidity generated inside the
enclosure. With increasing scientific understanding of the problems represented by moisture
and dampness and recognition of the widespread nature of these problems, all countries must
pay proper attention to how the quality of construction affects these problems. It is also
important to raise concern of the lack of legislation in regulating indoor mold and dampness. By
adding legislating this, we can control the morbidity and mortality caused by mold.
Summary
While dampness and mold seem like such a small thing to focus on changing, it has a
significant impact on the healthof the population. It is a major cause of morbidity and mortality
in the world, reducing the size of the working population by a large margin. By expanding this
topic and dwelling further to find solutions to the problem of indoor humidity and mold, the
working population can keep working and a decrease of medical costs will be seen as well.
Therefore, investing time into the prevention of dampness and mold indoors by using the
aforementioned methods can be very beneficial economic-wise and health-wise.

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References
1 Etzel RA et al. (1998). Acute pulmonary hemorrhage in infants associated with exposure to
Stachybotrys atra and other fungi. Archives of Pediatric and Adolescent Medicine, 152:757–
762.
2 Yoo CG et al. (1997) Summer-type hypersensitivity pneumonitis outside Japan: a case report
and the state of the art. Respirology, 2:75–77 .
3 Kauffman HF (2003). Immunopathogenesis of allergic bronchopulmonary aspergillosis and
airway remodeling. Frontiers in Bioscience, 8:e190–e196.
Other references
Stöppler, Melissa Conrad. "Mold Exposure: Get Facts About Symptoms and Treatment."
MedicineNet. Ed. William C. Shiel. N.p., n.d. Web. 10 Oct. 2015.
United States of America. Centers for Disease Control and Prevention. Centers for Disease
Control and Prevention, 22 May 2014. Web. <http://www.cdc.gov/mold/faqs.htm>.
World Health Organization. “WHO Guidelines for Indoor Air Quality: Dampness and Mold”.
http://www.euro.who.int/__data/assets/pdf_file/0017/43325/E92645.pdf.