sick building factsheet

7/27/2019 Sick Building Factsheet

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United States Air and Radiation (6609J) Research and DevelopmentEnvironmental Protection (MD-56)

Agency February 1991

Indoor Air Facts No. 4 (revised)

Sick Building Syndrome

Introduction

The term "sick building syndrome" (SBS) is used todescribe situations in which building occupantsexperience acute health and comfort effects thatappear to be linked to time spent in a building, butno specific illness or cause can be identified. Thecomplaints may be localized in a particular room or

zone, or may be widespread throughout thebuilding. In contrast, the term "building relatedillness" (BRI) is used when symptoms ofdiagnosable illness are identified and can beattributed directly to airborne building contaminants.

A 1984 World Health Organization Committeereport suggested that up to 30 percent of new andremodeled buildings worldwide may be the subjectof excessive complaints related to indoor air quality(IAQ). Often this condition is temporary, but somebuildings have long-term problems. Frequently,

problems result when a building is operated ormaintained in a manner that is inconsistent with itsoriginal design or prescribed operating procedures.Sometimes indoor air problems are a result of poorbuilding design or occupant activities.

Indicators of SBS include:

Building occupants complain of symptomsassociated with acute discomfort, e.g.,headache; eye, nose, or throat irritation; drycough; dry or itchy skin; dizziness and nausea;

difficulty in concentrating; fatigue; andsensitivity to odors.

The cause of the symptoms is not known.

Most of the complainants report relief soon afterleaving the building.

Indicators of BRI include:

Building occupants complain of symptoms suchas cough; chest tightness; fever, chills; andmuscle aches.

The symptoms can be clinically defined andhave clearly identifiable causes.

Complainants may require prolonged recoverytimes after leaving the building.

It is important to note that complaints may resultfrom other causes. These may include an illnesscontracted outside the building, acute sensitivity(e.g., allergies), job related stress or dissatisfactionand other psychosocial factors. Nevertheless,studies show that symptoms may be caused orexacerbated by indoor air quality problems.

Causes of Sick Building Syndrome

The following have been cited causes of orcontributing factors to sick building syndrome:

Inadequate ventilation:In the early and mid1900's, building ventilation standards called forapproximately 15 cubic feet per minute (cfm) ofoutside air for each building occupant, primarily todilute and remove body odors. As a result of the1973 oil embargo, however, national energyconservation measures called for a reduction in the

amount of outdoor air provided for ventilation to 5cfm per occupant. In many cases these reducedoutdoor air ventilation rates were found to beinadequate to maintain the health and comfort ofbuilding occupants. Inadequate ventilation, whichmay also occur if heating, ventilating, and airconditioning (HVAC) systems do not effectivelydistribute air to people in the building, is thought tobe an important factor in SBS. In an effort toachieve acceptable IAQ while minimizing energy


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consumption, the American Society of Heating,Refrigerating and Air-Conditioning Engineers(ASHRAE) recently revised its ventilation standardto provide a minimum of 15 cfm of outdoor air perperson (20 cfm/person in office spaces). Up to 60cfm/person may be required in some spaces (suchas smoking lounges) depending on the activities

that normally occur in that space (see ASHRAEStandard 62-1989).

Chemical contaminants from indoor sources:Most indoor air pollution comes from sources insidethe building. For example, adhesives, carpeting,upholstery, manufactured wood products, copymachines, pesticides, and cleaning agents mayemit volatile organic compounds (VOCs), includingformaldehyde. Environmental tobacco smokecontributes high levels of VOCs, other toxiccompounds, and respirable particulate matter.

Research shows that some VOCs can causechronic and acute health effects at highconcentrations, and some are known carcinogens.Low to moderate levels of multiple VOCs may alsoproduce acute reactions. Combustion productssuch as carbon monoxide, nitrogen dioxide, as wellas respirable particles, can come from unventedkerosene and gas space heaters, woodstoves,fireplaces and gas stoves.

Chemical contaminants from outdoor sources:The outdoor air that enters a building can be a

source of indoor air pollution. For example,pollutants from motor vehicle exhausts; plumbingvents, and building exhausts (e.g., bathrooms andkitchens) can enter the building through poorlylocated air intake vents, windows, and otheropenings. In addition, combustion products canenter a building from a nearby garage.

Biological contaminants:Bacteria, molds, pollen,and viruses are types of biological contaminants.These contaminants may breed in stagnant waterthat has accumulated in ducts, humidifiers anddrain pans, or where water has collected on ceilingtiles, carpeting, or insulation. Sometimes insects orbird droppings can be a source of biologicalcontaminants. Physical symptoms related tobiological contamination include cough, chesttightness, fever, chills, muscle aches, and allergicresponses such as mucous membrane irritationand upper respiratory congestion. One indoorbacterium, Legionella, has caused bothLegionnaire's Disease and Pontiac Fever.

These elements may act in combination, and maysupplement other complaints such as inadequatetemperature, humidity, or lighting. Even after abuilding investigation, however, the specific causesof the complaints may remain unknown.

A Word About Radon and Asbestos ...

SBS and BRI are associated with acute orimmediate health problems; radon and asbestoscause long-term diseases which occur years afterexposure, and are therefore not considered to beamong the causes of sick buildings. This is not tosay that the latter are not serious health risks; bothshould be included in any comprehensiveevaluation of a building's IAQ.

Building Investigation Procedures

The goal of a building investigation is to identify andsolve indoor air quality complaints in a way thatprevents them from recurring and which avoids thecreation of other problems. To achieve this goal, itis necessary for the investigator(s) to discoverwhether a complaint is actually related to indoor airquality, identify the cause of the complaint, anddetermine the most appropriate corrective actions.

An indoor air quali ty inves tigat ion p rocedureisbest characterized as a cycle of information

gathering, hypothesis formation, and hypothesistesting. It generally begins with a walkthroughinspection of the problem area to provideinformation about the four basic factors thatinfluence indoor air quality:

the occupants

the HVAC system

possible pollutant pathways

possible contaminant sources.

Preparation for a walkthroughshould include

documenting easily obtainable information aboutthe history of the building and of the complaints;identifying known HVAC zones and complaintareas; notifying occupants of the upcominginvestigation; and, identifying key individualsneeded for information and access. Thewalkthrough itself entails visual inspection of criticalbuilding areas and consultation with occupants andstaff.


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The initial walkthroughshould allow theinvestigator to develop some possible explanationsfor the complaint. At this point, the investigator mayhave sufficient information to formulate ahypothesis, test the hypothesis, and see if theproblem is solved. If it is, steps should be taken toensure that it does not recur. However, if

insufficient information is obtained from the walkthrough to construct a hypothesis, or if initial testsfail to reveal the problem, the investigator shouldmove on to collect additional information to allowformulation of additional hypotheses. The processof formulating hypotheses, testing them, andevaluating them continues until the problem issolved.

Al though air sampl ing for contaminants mightseem to be the logical responseto occupantcomplaints, it seldom provides information about

possible causes. While certain basicmeasurements, e.g., temperature, relative humidity,CO2, and air movement, can provide a useful"snapshot" of current building conditions, samplingfor specific pollutant concentrations is often notrequired to solve the problem and can even bemisleading. Contaminant concentration levels rarelyexceed existing standards and guidelines evenwhen occupants continue to report healthcomplaints. Air sampling should not be undertakenuntil considerable information on the factors listedabove has been collected, and any sampling

strategy should be based on a comprehensiveunderstanding of how the building operates and thenature of the complaints.

Solutions to Sick Building Syndrome

Solutions to sick building syndrome usually includecombinations of the following:

Pollutant source removal or modification is aneffective approach to resolving an IAQ problemwhen sources are known and control is feasible.Examples include routine maintenance of HVACsystems, e.g., periodic cleaning or replacement offilters; replacement of water-stained ceiling tile andcarpeting; institution of smoking restrictions; ventingcontaminant source emissions to the outdoors;storage and use of paints, adhesives, solvents, andpesticides in well ventilated areas, and use of thesepollutant sources during periods of non-occupancy;and allowing time for building materials in new orremodeled areas to off-gas pollutants beforeoccupancy. Several of these options may beexercised at one time.

Increasing ventilation ratesand air distributionoften can be a cost effective means of reducingindoor pollutant levels. HVAC systems should bedesigned, at a minimum, to meet ventilationstandards in local building codes; however, manysystems are not operated or maintained to ensurethat these design ventilation rates are provided. In

many buildings, IAQ can be improved by operatingthe HVAC system to at least its design standard,and to ASHRAE Standard 62-1989 if possible.When there are strong pollutant sources, localexhaust ventilation may be appropriate to exhaustcontaminated air directly from the building. Localexhaust ventilation is particularly recommended toremove pollutants that accumulate in specific areassuch as rest rooms, copy rooms, and printingfacilities. (For a more detailed discussion ofventilation, read Indoor Air Facts No. 3R,Ventilation and Air Quality in Office Buildings.)

Ai r c leaningcan be a useful adjunct to sourcecontrol and ventilation but has certain limitations.Particle control devices such as the typical furnacefilter are inexpensive but do not effectively capturesmall particles; high performance air filters capturethe smaller, respirable particles but are relativelyexpensive to install and operate. Mechanical filtersdo not remove gaseous pollutants. Some specificgaseous pollutants may be removed by adsorbentbeds, but these devices can be expensive andrequire frequent replacement of the adsorbent

material. In sum, air cleaners can be useful, buthave limited application.

Education and communicationare importantelements in both remedial and preventive indoor airquality management programs. When buildingoccupants, management, and maintenancepersonnel fully communicate and understand thecauses and consequences of IAQ problems, theycan work more effectively together to preventproblems from occurring, or to solve them if theydo.


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Addi tional Informat ion

For more information on topics discussed in thisFact Sheet, contact your state or local healthdepartment, a non-profit agency such as your local

American Lung Association, or the following:National Institute for Occupational Safety and

Health

www.cdc.gov/niosh/homepage.htmlUS Department of Health and Human Services4676 Columbia Parkway (Mail Drop R2)Cincinnati, Ohio 45226Public Relations Office

American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)www.ashrae.org/1791 Tullie Circle, NE,

Atlanta, Georgia 30329

Building Owners and Managers AssociationInternationalwww.boma.org/1250 Eye Street, NW,Washington, DC 20005

sick building factsheet

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