Sick Buildings

Definition, Diagnosis and Mitigation

Thad Godish

• Publisher: CRC Press
• Year: 2018
• ISBN:
  9781351416658
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

This book is a comprehensive examination of the phenomenon of poor indoor air quality (IAQ) characterized as sick or problem buildings. Significant emphasis is given to defining the nature of the problem, the various potential causal and risk factors, problem building diagnostic protocols and contaminant measurements, and the mitigation of IAQ problems, including case histories. The book features a discussion on the potential causal factors studied extensively in Europe and recognized in North America as well.

1. DEFINING THE ISSUES

We have become increasingly aware that human health and comfort complaints expressed by occupants of office, institutional, and other public access buildings are in many cases associated with poor indoor air quality (IAQ). When a building is subject to complaints sufficient to convince management to conduct an IAQ investigation, it may be characterized as a “problem” or “sick” building. Health complaints associated with a problem building may have a specific identifiable cause (building-related illness) or, as is true for many problem buildings, no specific causal factor or factors can be identified (sick building syndrome).

BUILDING-RELATED ILLNESS

When causal factors have been identified, the problem is described as “building-related illness” (BRI) or specific building-related illness (SBRI).¹² Building-related illnesses are usually characterized by a unique set of symptoms which may be accompanied by clinical signs, laboratory findings, and identifiable pollutants. Included in BRI or SBRI are nosocomial infections, the hypersensitivity diseases (such as hypersensitivity pneumonitis, humidifier fever, asthma, and allergic rhinitis), Legionnaires’ disease, fiberglass dermatitis, and direct toxic effects from exposures to contaminants such as carbon monoxide, ammonia, formaldehyde, etc. The term “building-related illness” was initially used to describe health problems associated with the formaldehyde contamination of residences³ and a variety of general symptoms associated with air quality in nonindustrial buildings.⁴

SICK BUILDING SYNDROME

“Sick building syndrome” (SBS) is used to describe a diffuse spectrum of symptoms in which no specific etiological factor can be identified.⁵ A working panel of the World Health Organization (WHO) initially attempted to define this phenomenon in the early 1980s.^6,7 Sick building syndrome was defined on the basis of a group of frequently reported symptoms or complaints including (1) sensory irritation in eyes, nose, and throat; (2) neurotoxic or general health problems; (3) skin irritation; (4) nonspecific hypersensitivity reactions; and (5) odor and taste sensations. Sensory irritation was described as pain, a feeling of dryness, smarting, stinging irritation, hoarseness or voice problems; neuro-toxic/general health problems as headache, sluggishness, mental fatigue, reduced memory, reduced capacity to concentrate, dizziness, intoxication, nausea and vomiting, and tiredness; skin irritation as pain, reddening, smarting, or itching sensations or dry skin; nonspecific hypersensitivity reactions as running nose or eyes, asthma-like symptoms among nonasthmatics, or sounds from the respiratory system; odor and taste sensations as changed sensitivity of olfactory or gustatory senses or unpleasant olfactory or gustatory perceptions.

In attempting to define and describe SBS, the WHO panel indicated that (1) mucous membrane irritation of the eyes, nose, and throat should be one of the most frequent symptom expressions; (2) other symptoms involving the lower respiratory airways and internal organs should be infrequent; (3) no evident causality should be identified in relation to occupant sensitivity or to excessive exposures; (4) symptoms should appear especially frequently in one building or part of it; and (5) a majority of occupants should report symptoms.

A sick building is distinguished from a normal one, under the WHO definition, by the prevalence of symptoms; that is, a large percentage of the occupants report symptoms. The reactions of a minority of building occupants who are unusually sensitive to exposures of indoor contaminants are not considered to be due to SBS. More than 30% of new buildings would be sick buildings according to WHO.

A working group of the Commission of European Communities (CEC) has described SBS as a phenomenon being experienced primarily by individuals working in climate-controlled buildings. They suggested that SBS was due to multiple factors and could only be diagnosed by exclusion, that is, by eliminating all other building-related health problems. Characteristic symptoms have been described as including nasal, ocular, oropharyngeal, cutaneous, and general (headaches, lethargy, general fatigue) manifestations, with a characteristic periodicity increasing with severity during the workday and resolving rapidly on leaving the building environment.

A working group of the American Thoracic Society (ATS) characterized SBS as having a subtle onset and progression, with cases being clustered within a building or areas of a building.² Symptom onset would occur as a consequence of being in a problem building with asymptomatic periods when absent. Characteristic symptoms would include eye irritation; headaches, clearing overnight and on weekends; recurrent fatigue, drowsiness, or dizziness; throat irritation without microbial etiology; chest burning, cough, sputum production in the absence of smoking or exposure to environmental tobacco smoke (ETS); wheezing or chest tightness with paroxysmal cough tending to continue but slowly improving on leaving the offending environment; malaise which may be associated with poor attention span and short-term memory problems; and rhinitis and nasal congestion without atopic history.

Though no specific etiological factors can be identified, SBS may be attributed to such factors as insufficient ventilation or thermal control, inadequate maintenance of building systems, changes in thermal or contaminant loads, changes in building operation to meet new objectives such as energy conservation, and inadequate design. Other contributing factors were described as being physical, chemical, biological, and psychosocial.

The constellation of symptoms characterizing SBS varies somewhat among the three working groups. Common to all are sensory irritation of eyes, nose, and throat and symptoms affecting the central nervous system (headaches, lethargy, fatigue). Both European panels identify skin symptoms as a part of the SBS complex; the American panel does not. The WHO and ATS working groups include pulmonary effects; the CEC working group does not. The WHO panel lists odor and taste sensations; the other two do not. Differences in symptomatologies described for SBS are likely due to differences in panel composition and differences in SBS symptom reporting in Europe and in North America. Symptom complexes described by WHO, CEC, and ATS working groups represent a range of human health responses. This apparent all-inclusive nature suggests that SBS is being defined on the basis of all symptoms of unknown causality which have been reported in sick building investigations.

The WHO characterization of SBS appears to be based on the theory that sick-building complaints of a sensory nature are a consequence of the nonspecific irritation or overstimulation of trigeminal nerves in mucous membranes, our so-called chemical sense. Trigeminal nerves respond to chemical odors that cause irritation, tickling, or burning. The major function of the trigeminal nerve system is to stimulate reflex actions such as sneezing or interruption of breathing when the human body is exposed to potentially harmful odor-producing substances. Similar physiological responses may be elicited by many different chemical substances.⁹

A subgroup of the WHO IAQ panel has suggested that indoor air contains a complex of sensory stimuli which produce irritant responses not specific to the individual contaminant exposures. As a consequence, no single contaminant can be said to be responsible. Additionally, reactions of the “referred pain type” may take place, so that facial skin sensations, headaches, etc. may be due to the irritation of trigeminal nerves in nasal mucosa. Upper airway symptoms, according to this theory, would be the net result of a summation of numerous subthreshold stimuli involving sensory systems after absorption of contaminants on nasal mucosa.¹⁰

The broad inclusion of symptoms/symptom types in definitions of SBS has been criticized by Hodgson” who suggests that each of the WHO symptom categories may represent various pathophysiologic entities, each recognized on its own. He suggests, for example, that eye and nose irritation may be due to allergenic contaminants, central nervous system symptoms to solvent neurotoxicity, skin complaints to photodermatitis from monovalent light or irritation from volatile organic compounds (VOCs) and low relative humidity, and odor complaints from contaminants or misperception of odors due to solvent neurotoxicity.

One of the problems in defining phenomena such as BRI and SBS is that such terms have been used interchangeably. The WHO subgroup¹⁰ indicated that SBS is synonymous with such terms as “building-related illness”, “building illness syndrome”, “ill buildings”, “stuffy offices”, and “tight office building syndrome”. Other synonyms have also included “tight building syndrome” and “stuffy building syndrome”.^11,12

A major difficulty in defining SBS is that one attempts to define that which is at best poorly understood. Any definition will, therefore, reflect the limits of our understanding. The WHO definition suggests a single phenomenon resulting from exposure to multiple substances which produce a similar effect, while multifactoral causal phenomena are suggested by the CEC panel.

TIGHT BUILDINGS

The term “tight building syndrome” began to be used in the late 1970s and early 1980s when it was widely believed that BRI and SBS phenomena were due to the implementation of energy conservation measures in the design, construction, and management of buildings. It is not clear what users of this term actually mean by it. Strictly speaking, a tight building is one that has been designed and constructed to attain and maintain low air infiltration conditions regardless of the percentage of outside air used for ventilation. Of course, when “tight buildings” were initially being designed and constructed, there was a concomitant move by building managers to reduce energy consumption and associated costs by reducing the amount of outdoor air used for ventilation in mechanically ventilated buildings. In many cases, buildings were operated on nearly 100% recirculated air. Such energy conservation practices were implemented in a broad range of mechanically ventilated buildings regardless of their “tightness” relative to air infiltration. Low outdoor exchange rates were being promoted as an energy conservation measure by a number of federal governments in northern Europe and North America. Ventilation standards^13,15 reflected the appeal of low outdoor air requirements to minimize energy costs. For many users of the term, it appears that a tight building is one with low regulated inflows of outdoor air regardless of whether it is, in the strict sense of the word, a “tight” building.

Several investigators¹⁶’¹⁷ have suggested that sick-building complaints are for the most part associated with modern sealed buildings described as air-tight shells¹⁶ in which individual occupants cannot directly control their personal comfort (temperature, humidity, ventilation). It is for such individuals “a tight building”. Those who have advocated the use of the term suggest that the preponderance of sick-building complaints have arisen in new, energy-efficient buildings,¹⁷ though there appears to be little documented evidence of this.

Both the initial and continued use of the “tight building” concept is unfortunate. It is simplistic at best to attempt to characterize problem-building complaints as being caused by the design, construction, and operation of new, energy-efficient buildings. Such buildings represent only a fraction of the total building population, and there is considerable evidence to suggest that sick building-type symptoms are common to many buildings, including many which are not “tight buildings”. Intuitively, the use of low outdoor ventilation rates as an energy conservation measure would be expected to be a significant contributing factor to SBS. However, there is little scientific evidence to support a direct relationship between SBS symptoms and ventilation rates (see Chapters 3 and 8).

SICK BUILDINGS/PROBLEM BUILDINGS

It is common to describe buildings subject to complaints as being sick or problem buildings. Molhave¹⁸ suggests that the term “problem building” be applied to those buildings in which occupants are dissatisfied with air quality for any reason, with the term “sick building” reserved for a subpopulation of a larger set of “problem buildings”. Molhave¹⁸ describes sick buildings as having no exposure factor exceeding any generally accepted dose-response threshold, with causality being multifactoral. Causality could be due to an unknown exposure factor or factors and/or to an unknown reaction to the already known exposure factor.

Molhave’s¹⁸ characterization of sick buildings as being a subset of a larger population of problem buildings characterized by unknown etiological factors makes good scientific sense. Unfortunately, the terms “problem” and “sick building” are often used interchangeably. The term “sick building” also implies that a building is sick. Being nonhuman, of course, a building can only be sick in a metaphorical sense.

Field Investigations

An apparent relationship between building environments and complaints of illness by occupants became evident from what has been described ...

Table of contents

• Cover
• Title Page
• Copyright
• Table of Contents
• Preface
• 1. Defining the Issues
• 2. People-Related Risk Factors
• 3. Environmental Conditions/Environmental Systems
• 4. Office Materials, Equipment, and Furnishings
• 5. Gas/Vapor- and Particulate-Phase Contaminants
• 6. Contaminants of Biological Origin
• 7. Diagnosing Problem Buildings
• 8. Measurement of Indoor Air Contaminants
• 9. Source Control
• 10. Contaminant Control
• Index