The World Health Organization defines Sick Building Syndrome as a complex of sub-chronic symptoms that occur while occupants are in a building and generally decrease when they leave. The EPA defines it as “phenomena used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified.” The discomforts faced by the occupants are usually of the dermis, the nervous system and the mucous membranes (Brinke et al., 1998). Typical symptoms may include itchy eyes, itchy and/or dry skin, irritation of the nose, throat, difficulty in breathing, headache, nausea, fatigue, chest tightening etc. (Apter et al, 1994). The problem may not necessarily be one related to the place of occupation, but studies that describe it refer almost specifically to occupation related disorders.
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Sick building syndrome is a by-product of building related illness which itself is an extension of indoor air quality. SBS is hard to diagnose as the symptoms that accompany it are not mutually exclusive to it, and may also be the manifestations of other illnesses. Previous studies and surveys conducted on office buildings in the U.S and Europe indicate that at least a 5th of the healthy individuals in the building experience symptoms related to SBS (Pickering et al.,1992) . Usually however, the symptoms disappear if the person leaves the building.
2. CAUSES OF SBS
The following are the possible causes of sick building syndrome:
2.1. Ventilation (or lack thereof)
In the mid 1900s the building ventilation standards were set at approximately 15 cubic feet per minute (cfm) of outside air for each building occupant, primarily to dilute and remove body odors (US EPA). As a result of the 1973 oil embargo, however, national energy conservation measures called for a reduction of the amount of outdoor air provided for ventilation to 5 cfm per occupant, which in most cases were found to be inadequate. Inadequate ventilation may also occur if heating, ventilating, and air conditioning (HVAC) systems do not effectively distribute air to people in the building(US EPA).
To maintain adequate indoor air quality, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recently revised its ventilation standard to provide a minimum of 15 cfm of outdoor air per person (20 cfm/person in office spaces). ( ASHRAE Standard 62-1989).
2.2. Contaminants
Contaminants are of a varied nature and varied origin. They can be broadly categorized into two categories on the basis of their composition i.e. chemical and biological; and their origin i.e. indoor and outdoor.
2.2.1 Indoor chemical contaminants
These originate inside the building. Examples could be chemicals/fumes from the paint, carpeting, wood products, upholstery, copying machines, computers, cleaning agents. Such chemicals are usually classified as Volatile Organic Carbons. Other chemical contaminants can be the CO2 exhaled in totality, the fumes/chemicals in cigarette smoke. Heating systems especially the old ones can give rise to combustion byproducts such as carbon monoxide, nitrogen dioxides, aerosol particles, ozone etc. Various studies have been conducted on almost all of the above mentioned chemicals contaminants and their ill effects have been well documented.
2.2.2. Outdoor chemical contaminants
As the name suggest, these originate outside the building. These also include VOCs, gases like carbon monoxide, nitrogen dioxide, oxides of sulfur, ozone, etc. However, the basic difference between this and indoor chemical contaminants is that outdoor contaminants arise due to vehicular use outside the building, which gradually pervades inside the building.
2.2.3. Biological contaminants
Bacteria, molds, pollen, and viruses are types of biological contaminants. These contaminants may breed in stagnant water that has accumulated in ducts, humidifiers and drain pans, or where water has collected on ceiling tiles, carpeting, or insulation. Sometimes insects or bird droppings can be a source of biological contaminants.
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. One indoor bacterium, Legionella, has caused both Legionnaire’s Disease and Pontiac Fever (Apter et al, 1994).
3. EPIDEMIOLOGY OF SICK BUILDING SYNDROME
Several studies have been conducted on the Sick Building Syndrome, and the effects related to it. These studies had employed questionnaires which depended on self-reporting by the subjects, and indoor quality measurements. The first of such surveys/studies which focused primarily on building related sickness or complaints was done in the United Kingdom for ‘humidifier fever’ by Anthony Pickering (Pickering et al, 1992). The same method was utilized by the subsequent researchers, with some modifications in the study design or questions. The studies were usually comparative, i.e. there was a test group in which the subjects worked/resided in not so well ventilated buildings, and the control group in which the subjects were in well ventilated buildings. Self reporting was usually a component of the study design (Redlich et at, 1997), and by its very nature the most likely to introduce bias in the study. Subjects usually reported nasal symptoms such as congestion, pruritis, rhinorrhea etc., eye related symptoms such as tearing, dryness etc., and others such as tightness and congestion in the chest area, nausea etc. (Apter et al, 1994). When comparisons were made between the two groups, it was seen that the prevalence of all these symptoms was higher in the subjects that were in the test group. This would help to draw the conclusion that there was some factor in the building, possibly the ventilation or lack of it that contributed to these symptoms. Though building related factors are not the only variables in such studies, age, gender, environmental factors also account for a lot. A study conducted by Ooi et al. suggests that building related health complaints were reported more frequently by people who handled/dealt with visual display units.
A majority of the researchers conducting these studies agree that these symptoms could also be manifestations of work related stress, which obviously plays a major part in today’s work environment. Stress related disorders include headaches including migraines, peptic ulcers, high blood pressure, bronchial asthma etc. When these are considered in conjugation with building related health complaints, there is a very high degree of overlap. Indoor air quality measurements usually help to somewhat pinpoint the origin of these disorders, if not accurately predict them. Air quality measurements with respect to building related disorders prove that inadequate ventilation is usually a major cause of the disorders. Inadequate ventilation fails to dissipate the concentration of the chemical and biological contaminants, and may even lead the increase in their concentration over time. Sources of these contaminants will be discussed further.
3.1. Sources of the Contaminants
A).VOCs: Volatile organic compounds are usually aerosols of hydrocarbons. They arise from various sources and are present in a variety of compounds present indoors. Such sources are paints, coatings, caulks, carpeting, Office products such as type-writer correction fluids, photo-duplication and laser printing toners and their thermal degradation products, and carbonless copy paper release. In addition, perfumes, emissions from dry-cleaned clothes, and other products associated with human beings may give of VOCs. Also certain microorganisms such as bacteria or fungi may emit VOCs (Brinke et al, 1998).
B). BIOAEROSOLS: As the name suggests, these are released by biological sources such as micro-organisms and even humans. Plants also emit bioaerosols. Inadequate cleaning services and moisture control may lead to the proliferation of microorganisms. Furthermore, dust may collect in vents and in between carpeting (Apte et al., 2000). Workers may even carry them in through their clothes, and these are the major ways how organisms such as dust mites, cockroaches and even bed bugs are transported and subsequently propagated. These compounds usually give rise to respiratory illnesses and can increase the incidence of asthma, though their epidemiology is not much supported by previous studies.
C). ENVIRONMENTAL TOBACCO SMOKE: In most U.S office buildings, smoking is prohibited. However, already present outside smoke may pervade in through doorways and windows through wind patterns. Usually tobacco smoke is not much of a problem in the United States; however, it is so in many other countries especially developing countries. Such a factor may increase passive smoking, and increase the incidence of asthma, and other respiratory diseases.
D). OUTSIDE AIR POLLUTION: Vehicular exhaust, factory exhaust and other outdoor pollution factors can pervade indoors gradually. This is seen in buildings which are near busy roadways and city centers. The compounds in such are usually VOCs and aerosols which cause a huge variety of problems (Brinke et al, 1998).
E). PSYCHOLOGICAL FACTORS: Work stress is a psychological factor that can exacerbate already existing health problems and/or make a person more susceptible to them.
Furthermore, several studies have proved that gender and age play a big part in the prevalence of the disorders. Typically, women and older workers are more susceptible to sick building syndrome disorders (Brasche et al, 2001).
4. POSSIBLE REMEDIATION OF SICK BUILDING SYNDROME
Sick building syndrome is different from building related illness in the sense that it is reversible, i.e. most people report alleviation in their symptoms if they leave the building. This ‘improvement’ in their health is more or less fast, and it is this factor that makes SBS somewhat easy to manage. The following solutions can be used in combination or separately to remediate these symptoms.
4.1. Elimination of contaminants
This method is the best remedy if the sources are known and it is economically feasible to remove them. A well maintained HVAC system can automatically help to eradicate some or most of these pollutants. The EPA suggests the following procedures to help in eliminating the contaminants:
1. Periodic cleaning or replacement of filters
2. Replacement of water-stained ceiling tile and carpeting
3. Institution of smoking restrictions
4. Venting contaminant source emissions to the outdoors
5. Storage and use of paints, adhesives, solvents, and pesticides in well ventilated areas, and use of these pollutant sources during periods of non-occupancy
6. Allowing time for building materials in new or remodeled areas to off-gas pollutants before occupancy.
4.2. Increasing ventilation rates
Improving ventilation and the general air distribution greatly impacts the indoor air quality of a building. It is usually the most economically feasible options of counteracting SBS. HVAC should at the very least meet the minimum standards of local and/or national building codes.
The ASHRAE suggests operating HVAC systems at their design optimum which is usually better and higher than the generic codes. The most optimum and the best option to operate HVAC systems is to the ASHRAE standard62-1989.
If there is a large proportion of outdoor pollution pervading indoors, the exhaust systems have to operate to their most optimum capacity so as to continually eliminate such contaminants. Another plausible but far less economically plausible option could be to avoid such congested areas altogether, and build new buildings in comparatively more open spaces, however, this could lead to the reduction in a place’s green cover, and would be ultimately counter-intuitive to the purpose of elimination of air pollution.
The EPA recommends local exhaust ventilation to remove pollutants that accumulate in specific areas such as rest rooms, copy rooms, and printing facilities. It also recommends that the HVAC systems must bring in adequate amounts of outdoor air to dilute and eventually remove indoor contaminants.
4.3. Air cleaning
Air cleaning is usually a good remediation option if the SBS is too much, or the indoor air quality is too deteriorated. It is more of a ‘cure’ than a prevention strategy. Like most mechanical cures, this option also comes with a lot of limitations. Particle control devices such as the typical furnace filter are inexpensive but do not effectively capture small particles whereas high performance air filters capture the smaller, respirable particles but are relatively expensive to install and operate. Mechanical filters do not remove gaseous pollutants. Some specific gaseous pollutants may be removed by adsorbent beds, but these devices can be expensive and require frequent replacement of the adsorbent material (Wargocki et al, 2000).
4.4. Proper Communication and Education
These are one of the most important measures in remediation and prevention of SBS. The top management needs to keep in mind the health of its employees and should communicate measures to help them. All the levels of the management must work in tandem to maintain good or rather excellent indoor air quality. The EPA eloquently puts it as “When building occupants, management, and maintenance personnel fully communicate and understand the causes and consequences of IAQ problems, they can work more effectively together to prevent problems from occurring, or to solve them if they do.”
5. CONCLUSION
Sick Building Syndrome is increasingly becoming an issue in the workplace and there are documented proofs that it results in reduction in productivity. However, thankfully, it is a reversible and easily remediable phenomenon, and if the employers and employees work together in eliminating it, it can truly be eradicated.
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