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Sick Building Syndrome (SBS) Sources

Sick building syndrome (SBS) is a problem in Hong Kong, a government funded survey found that 30% of buildings were sick.

The following have been cited as causes of or contributing factors to sick building syndrome (SBS).

It should be noted that in different area SBS is known by different terminology. For example, tight buildings - referring to limited fresh air, building related illness, etc.

Market Conditions

During the early 1970's a dramatic energy crisis swept the globe, and demanded an immediate need for energy conservation measures.

Amongst other measures, reduced quantities of outdoor air provided were targeted as a short cut to lower energy consumption.

In many cases the reduced outdoor air ventilation rates were found to be inadequate to maintain the health and comfort of building occupants and ineffective air distribution compounding the problem. Licensed restaurants in Hong Kong only need to provide minimum quantities of "fresh" outside air, much less than CIBSE or ASHRAE recommendations.

Chemical Contaminants (Interior)

Most indoor air pollution comes from within the building.  For example, adhesives, carpeting, upholstery, manufactured wood products, paint photocopy machines, pesticides, and cleaning agents may emit volatile organic compounds (VOC), including formaldehyde.

Environmental tobacco smoke contributes high levels of potentially toxic compounds and particulates. Research indicates that some VOC's can cause chronic and acute health effects at high concentrations.

Some are known carcinogens, where relatively low levels may also cause an acute reaction.

Products of combustion such as, carbon monoxide, nitrogen dioxide and sulphur that are generated by heaters, boiler plant, gas space heaters and stoves which can, under certain conditions, be found in the occupied area.

Chemical Contaminants (Exterior)

The local environment is polluted especially, inner city areas. The "fresh" outdoor air that is drawn into building by ventilation systems contains motor vehicle exhaust, odours and products from other building, for example cooling towers and restaurants

A poorly designed ventilation system may introduce these pollutants in to building:

  • Exhaust flues, combustion plumes, and drainages stacks poorly located near air inlets louvres
  • Fenestration and Infiltration
  • Cooling Tower mist and chemical
  • Other unauthorised openings

Biological Contaminants

Biological contaminants, include bacterium, mould, pollen and viruses. These contaminants can grow if favourable conditions are found in the building, example include:

  • Stagnant water accumulated in ductwork, humidifiers and air handling equipment.
  • water damaged materials including ceiling tiles, carpeting, or thermal insulation.
  • Animals, insects or birds

Physical symptoms related to biological contamination include cough, chest tightness, fever, chills, muscle aches, and allergic responses such as mucous membrane irritation and upper respiratory congestion.

Seldom do we locate a single biological contaminant source that causes building complaints or illness, more often, a combination of pollutants is found, which is coupled with other building related problems. One particular bacterium, Legionella, causes both Legionnaires' Disease and Pontiac fever. For more information about Legionella read our Legionnaires Disease FAQ


Asbestos is rare in modern buildings, however still found in certain construction materials, learn more about asbestos

Further information

For a professional building assessment ask your manager for an independent assessment - contact the experts Kelcroft

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