Sick Building Syndrome: Risk Factors
Introduction
Sick building syndrome (SBS) has been reported since the 1960s, with increasing reports in the 1970s and 1980s of health problems in office environments. The World Health Organization (WHO), in 1986, estimated that approximately 30% of new or refurbished buildings had high complaint levels of ill health and discomfort at work. The use of the term SBS highlights the difference between it and building-related illness. Building-related illnesses are usually linked to an organic cause such as legionnaires’ disease. Other building-related illnesses include humidifier fever and, potentially, occupational asthma.
SBS symptoms and associations
Since descriptions began to circulate in relation to SBS, a number of common, if non-specific, symptoms were occurring in the office environment. These were summarised by the WHO as:
- Irritated dry or watering eyes
- Irritated runny or blocked nose
- Dry or sore throat
- Dryness, itching or irritation of the skin, occasionally with a rash
- Headaches, lethargy, irritability and poor concentration.
A number of issues do occur when reporting non-specific symptoms. First, it is estimated that 15–30% of people suffer from these symptoms away from the workplace. In relation to identifying sick building cases in the work environment, one of the key definitions is the relief of symptoms away from the workplace.
Different buildings, different air
Research studies have also identified different building factors that are linked to increased reporting. Naturally ventilated buildings have fewer symptoms reported when compared to air-conditioned office environments. Although air quality is found to be better in air-conditioned buildings, the reporting pattern remains the same. Symptom reporting patterns have also found increased reporting in public service buildings compared to private sector buildings. One study that examined a shared private building in which there were both private sector and public sector workers found no difference. This suggests that it may relate to the quality of materials, more open-plan working, poorer maintenance standards and the type of work being carried out within public sector buildings.
The type of office worked in also has an impact on symptom reporting. People working in smaller offices of up to four individuals per office report fewer symptoms than those in open-plan offices.
Several indoor environmental factors have been identified as contributing to SBS. Symptom reporting has been associated with ventilation rates of less than 10 litres per minute per person. Studies where there was no association between symptoms and ventilations rates generally had a higher (more than 10 per minute per person) rate of ventilation.
Temperature and humidity
There is also a link between higher temperatures and increased symptom reporting. This has been found when temperatures are 23°C or above. A link has also been found between increasing temperature, inadequate ventilation and overcrowding, but understanding the routes of causation are difficult.
Relative humidity in the office environment is often dependent on the levels of humidity outside, and symptoms such as stuffy noses, dry throats, thirst and contact lens problems are related to low levels of humidity. However, the use of humidifiers within the ventilation system can allow an environment for bacteria to grow. To prevent this, biocides can be added to the ventilation system but those may also contain irritants or allergens to which the building population will be exposed.
Dust and fumes
The effect of dust and airborne particles within the office environment has also been widely discussed. Levels of paper dust, carbonless copy paper and fumes from printers and photocopiers correlate with increased reporting of symptoms. Exposure to paper dust and fume is associated with respiratory and skin symptoms. Exposure to carbonless copy paper is found to increase the risk of reporting eye symptoms and breathlessness. Cell culture tests have revealed an inflammatory potential between indoor settled dust and SBS symptoms. Thus, surfaces left dusty may have the potential to exacerbate symptoms and this includes shelving, carpets and flooring.
Volatile Organic Compounds (VOCs)
Volatile organic compounds (VOCs) have also been suggested as a potential source of symptoms. There are numerous sources of such chemicals in the indoor environment including building materials and products such as inks and cleaning fluids used. No consistent associations have been found generally but for specific chemicals including formaldehyde and ozone, correlations between exposure and SBS symptoms have been found.
Reporting rates
Different symptom reporting rates are identified within different groups. Women report more symptoms than men, and those in lower status jobs also report more symptoms. The reasons behind this are unclear as to whether women are more ready to complain about ill-health symptoms or if lower grade staff spend more time in one specific environment.
Visual Display Units (VDUs)
The use of visual display units (VDUs) has also been associated with increased SBS symptom reporting, with the number of hours working at a VDU being linked to symptoms. Again, the linkages between using a computer and symptom reporting are not clear. The use of VDUs may disturb blinking behaviour in some individuals and cause eye symptoms. However, working at a VDU for extended periods may be related to being a particular grade of staff, with fewer opportunities for control at work and subjected to high demands.
Environment control
Control over the environment has also been seen as an issue for those reporting SBS, with increased SBS symptom reporting linked to a lack of environment control. In many large offices, staff cannot dictate levels of ventilation, lighting or noise.
Occupational stress
When psychological and personality factors are examined, Crawford and Bolas (1996) reviewed the link between work factors, occupational stress and SBS. The review identified that occupational stress has been found to correlate with SBS symptom reporting. It has been hypothesised that stress sensitises the individual to the effect of physical factors within a building. What was unclear was whether stress contributes to increased symptom reporting or whether SBS is the outcome of a stress response.