Causes & Consequences of Poor Internal Air Quality
Humidity
Inadequate levels of humidity, whether too high or too low, can compromise the internal air quality of a building. Humidity levels are primarily influenced by the suitability of the ventilation. Humidity levels that are either too high or too low are easily identified. Extreme levels have negative impacts on the health of building occupants and the life span of internal fittings.
Negative health effects of an internal dry atmosphere include dry skin and eyes.
Effects on the building interior include:
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dulling of polished surfaces
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damage to wooden furniture and fi ttings
Negative health effects of a moist atmosphere include:
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respiratory illness due to increased levels of mould spores and dust mites which thrive in moist environments
Effects on building interiors are greater than those for a dry environment. These include:
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mould and mildew
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damp or wet walls
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damaged wallpaper and plaster boards
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warped doors and windows
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condensation
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less efficient heating plant
Odour
Particular types of service/retail outlet such as hairdressing salons, dry cleaning outlets, and restaurants can release overpowering smells which often cause nuisance impact to neighbouring residents and workers.
Dust
Dust is generated by many daily activities, including the construction process. Activities such as demolition, mixing, blasting, cutting, grinding, etc. can all generate high levels of dust, if best practice attenuation measures are not adopted. Dust is a well known cause of respiratory irritation. Substantial amounts of dust in an operational building can present a significant problem for allergy sufferers.
Asbestos
It is estimated that around 5.5m UK buildings contain asbestos, which before the health impacts were known, was considered to be the perfect fire retardant material. Asbestos can therefore be found in many existing building components including:
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cladding
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insulation
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flue-pipes
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storage heaters
Asbestos poses a very high risk to human health, as it is carcinogenic and via inhalation, can lead to lung, chest and abdominal cancer. At least 3500 people in the UK die each year from mesothelioma and asbestos related lung cancer as a result of past exposure to asbestos, and such figures are expected to rise within the next decade.
Asbestos has long been prohibited from any building works and asbestos management and removal is highly regulated. More information can be found at: www.hse.gov.uk/asbestos/
Volatile organic compounds
Volatile Organic Compounds (VOCs) are air borne substances that are released from materials and furnishings such as plastics and MDF, finishing products such as paints and varnishes and offi ce equipment such as photocopiers. External sources of VOCs include motor vehicles and aircraft. Known human health hazards arising from inhalation of VOCs include:
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breathing difficulties
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eye, skin and throat irritation
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nausea
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allergic reactions
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increased risk of lung disease
Biological contaminants
These include bacteria, moulds, pollen and viruses, which can occur in stagnant water accumulated in ducts, humidifi ers and drains, or water stained ceiling tiles, carpeting or insulation. Other sources of biological contaminants include insects or birds droppings.
Common health impacts include:
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coughing
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chest tightness
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chills
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fever
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muscle aches
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various forms of allergic responses
One particular type of bacteria posing extreme risk is Legionella, which causes Legionnaire’s Disease (a fatal form of pneumonia), and Pontiac Fever. Legionnaire’s disease develops in poorly maintained and intermittently used water tanks and plant, boilers and pipework. Clear design guidance on how to remove all Legionnaire’s risk from building services is available from the Chartered Institute of Building Services Engineers (CIBSE).
Sick building syndrome
Sick Building Syndrome can be caused by the range of factors explained above, such as airborne pollutants released from buildings, VOCs, low humidity, ozone, dust mite and also glare. Common symptoms include lethargy, stuffy or runny nose, dry throat, headache, eye irritation, chest tightness and dry skin.
Building services
Building services emit a large proportion of major greenhouse gases such as Carbon Dioxide (CO2), Sulphur Dioxide (SO2) and Nitrous Oxide (NO), and various other gases.
Building services account for around 25% of UK annual Sulphur Dioxide (SO2) and Nitrous Oxides (NOx) emissions. These two gases contribute to the acidifi cation process, which pollutes soils, watercourses and forestry. Acidification also damages limestone buildings and statues.
In addition to SO2 and NOx, other key air pollutants generated by building services include refrigerants (used in air conditioning). Although refrigerant gases are mostly inert and consequently do not present a threat to human health, they have Global Warming Potential and can also have Ozone Depletion Potential. This means that when they leak/are accidentally released from air handling units, fan coils and chillers, they contribute significantly to ozone depletion and the greenhouse effect.
Particulates
PM10 are particles that have a diameter of less than 10µm. Road traffic is the primary source of particulates outdoors. Sources of internal particulates include smoking, burning of candles, coal or wood fires and cooking. Health implications arising from the inhalation of these solid substances are:
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eye irritation
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nose, throat and respiratory disease
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bronchitis, emphysema and heart disease can be caused when those particles are absorbed into the blood stream.
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cancer
