Influence of micro-organisms on the
air
Most of our life is spent indoors.
Therefore, indoor air pollution may present a greater risk to human health than
exposure to atmospheric air contaminants. One kind of indoor air pollutant is
airborne microorganisms – bacteria and fungi. They are factors of potential
infectious, allergenic and immunotoxic effects. Indoor microflora is reported
to be responsible for health problems, especially among children. Bioaerosols
decrease air quality and affect human health, also causing some diseases such
as tuberculosis, diphteria, legionellosis, fever, rhinitis, nausea and asthma.
The activity of people and equipment
within enclosed spaces is thought to be the principal factor contributing to
the buildup and spread of airborne microbial contamination. Another major
emission sources of indoor microbiological pollutants are animals, plants, air
conditioning systems, building materials, particles of soil and dust. A lot of
these come from outdoor air, especially in summer and autumn. School facilities
are densely populated, so it’s making the problem of maintaining good quality
indoor environments more difficult.
Poor indoor air quality causes in many
cases illness requiring absence from school or can cause acute health symptoms,
decreasing performance while at school. Children are more likely to suffer the
consequences of indoor pollutants than adults, because they are still
developing physically. It has been stated that especially the presence of
moulds in indoor air of schools poses a serious risk to children. All moulds
have the potential to cause health effects such as headaches, breathing
difficulties, skin irritation, allergic reaction and aggravation of asthma
symptoms. Epidemiological data suggest that mould exposure may increase the
risk for asthma up to five-fold at school age.
Asthma is the principal cause of school
absences (up to 20% of lost school days in elementary and high schools). Also,
14% of school children revealed a positive reaction to fungal allergens in skin
prick tests and serum IgE reactions. An elevated occurrences of wheezing and
fever in children was connected with high numbers of fungi in the air. To
estimate a hazard of microbiological air pollution a number of fungi and
various groups of bacteria indoors should be determined, as precisely as
possible.
World Health Organization (WHO)
guidelines for the protection of public health from health risks due to
dampness, associated microbial growth and contamination of indoor spaces. The
guidelines are based on a comprehensive review and evaluation of the
accumulated scientific evidence by a multidisciplinary group of experts
studying health effects of indoor air pollutants as well as those specialized
in identification of the factors that contribute to microbial growth indoors.
Problems of indoor air quality are
recognized as important risk factors for human health in both low-income and
middle- and high-income countries. Indoor air is also important because
populations spend a substantial fraction of time within buildings. In
residences, day-care centers, retirement homes and other special environments,
indoor air pollution affects population groups that are particularly vulnerable
due to their health status or age. Microbial pollution involves hundreds of
species of bacteria and fungi that grow indoors when sufficient moisture is
available. Exposure to microbial contaminants is clinically associated with
respiratory symptoms, allergies, asthma and immunological reactions.
The microbial indoor air pollutants of
relevance to health are widely heterogeneous, ranging from pollen and spores of
plants coming mainly from outdoors, to bacteria, fungi, algae and some protozoa
emitted outdoors or indoors. They also include a wide variety of microbes and
allergens that spread from person to person. There is strong evidence regarding
the hazards posed by several biological agents that pollute indoor air;
however, the WHO working group convened in October 2006 concluded that the
individual species of microbes and other biological agents that are responsible
for health effects cannot be identified. This is due to the fact that people
are often exposed to multiple agents simultaneously, to complexities in
accurately estimating exposure and to the large numbers of symptoms and health
outcomes due to exposure.
The exceptions include some common
allergies, which can be attributed to specific agents, such as house-dust mites
and pets. The presence of many biological agents in the indoor environment is
due to dampness and inadequate ventilation. Excess moisture on almost all
indoor materials leads to growth of microbes, such as mould, fungi and
bacteria, which subsequently emit spores, cells, fragments and volatile organic
compounds into indoor air. Moreover, dampness initiates chemical or biological
degradation of materials, which also pollutes indoor air. Dampness has
therefore been suggested to be a strong, consistent indicator of risk of asthma
and respiratory symptoms (e.g. cough and wheeze). The health risks of
biological contaminants of indoor air could thus be addressed by considering
dampness as the risk indicator.
The indoor environment in any building is a result of
the interaction between the site, climate, building system (original design and
later modifications in the structure and mechanical systems), construction
techniques, contaminant sources (building materials and furnishings, moisture,
processes and activities within the building and outdoor sources) and building
occupants. Microbial sources may arise from pollen, dust or fungal spores.
Stagnant water in the vicinity of buildings may also give rise to microbial
sources which may ca
Most of our life is spent indoors.
Therefore, indoor air pollution may present a greater risk to human health than
exposure to atmospheric air contaminants. One kind of indoor air pollutant is
airborne microorganisms – bacteria and fungi. They are factors of potential
infectious, allergenic and immunotoxic effects. Indoor microflora is reported
to be responsible for health problems, especially among children. Bioaerosols
decrease air quality and affect human health, also causing some diseases such
as tuberculosis, diphteria, legionellosis, fever, rhinitis, nausea and asthma.
The activity of people and equipment
within enclosed spaces is thought to be the principal factor contributing to
the buildup and spread of airborne microbial contamination. Another major
emission sources of indoor microbiological pollutants are animals, plants, air
conditioning systems, building materials, particles of soil and dust. A lot of
these come from outdoor air, especially in summer and autumn. School facilities
are densely populated, so it’s making the problem of maintaining good quality
indoor environments more difficult.
Poor indoor air quality causes in many
cases illness requiring absence from school or can cause acute health symptoms,
decreasing performance while at school. Children are more likely to suffer the
consequences of indoor pollutants than adults, because they are still
developing physically. It has been stated that especially the presence of
moulds in indoor air of schools poses a serious risk to children. All moulds
have the potential to cause health effects such as headaches, breathing
difficulties, skin irritation, allergic reaction and aggravation of asthma
symptoms. Epidemiological data suggest that mould exposure may increase the
risk for asthma up to five-fold at school age.
Asthma is the principal cause of school
absences (up to 20% of lost school days in elementary and high schools). Also,
14% of school children revealed a positive reaction to fungal allergens in skin
prick tests and serum IgE reactions. An elevated occurrences of wheezing and
fever in children was connected with high numbers of fungi in the air. To
estimate a hazard of microbiological air pollution a number of fungi and
various groups of bacteria indoors should be determined, as precisely as
possible.
World Health Organization (WHO)
guidelines for the protection of public health from health risks due to
dampness, associated microbial growth and contamination of indoor spaces. The
guidelines are based on a comprehensive review and evaluation of the
accumulated scientific evidence by a multidisciplinary group of experts
studying health effects of indoor air pollutants as well as those specialized
in identification of the factors that contribute to microbial growth indoors.
Problems of indoor air quality are
recognized as important risk factors for human health in both low-income and
middle- and high-income countries. Indoor air is also important because
populations spend a substantial fraction of time within buildings. In
residences, day-care centers, retirement homes and other special environments,
indoor air pollution affects population groups that are particularly vulnerable
due to their health status or age. Microbial pollution involves hundreds of
species of bacteria and fungi that grow indoors when sufficient moisture is
available. Exposure to microbial contaminants is clinically associated with
respiratory symptoms, allergies, asthma and immunological reactions.
The microbial indoor air pollutants of
relevance to health are widely heterogeneous, ranging from pollen and spores of
plants coming mainly from outdoors, to bacteria, fungi, algae and some protozoa
emitted outdoors or indoors. They also include a wide variety of microbes and
allergens that spread from person to person. There is strong evidence regarding
the hazards posed by several biological agents that pollute indoor air;
however, the WHO working group convened in October 2006 concluded that the
individual species of microbes and other biological agents that are responsible
for health effects cannot be identified. This is due to the fact that people
are often exposed to multiple agents simultaneously, to complexities in
accurately estimating exposure and to the large numbers of symptoms and health
outcomes due to exposure.
The exceptions include some common
allergies, which can be attributed to specific agents, such as house-dust mites
and pets. The presence of many biological agents in the indoor environment is
due to dampness and inadequate ventilation. Excess moisture on almost all
indoor materials leads to growth of microbes, such as mould, fungi and
bacteria, which subsequently emit spores, cells, fragments and volatile organic
compounds into indoor air. Moreover, dampness initiates chemical or biological
degradation of materials, which also pollutes indoor air. Dampness has
therefore been suggested to be a strong, consistent indicator of risk of asthma
and respiratory symptoms (e.g. cough and wheeze). The health risks of
biological contaminants of indoor air could thus be addressed by considering
dampness as the risk indicator.
The indoor environment in any building is a result of
the interaction between the site, climate, building system (original design and
later modifications in the structure and mechanical systems), construction
techniques, contaminant sources (building materials and furnishings, moisture,
processes and activities within the building and outdoor sources) and building
occupants. Microbial sources may arise from pollen, dust or fungal spores.
Stagnant water in the vicinity of buildings may also give rise to microbial
sources which may ca
ليست هناك تعليقات:
إرسال تعليق