Chair Subcommittee on Indoor Air Quality University of Nevada Las Vega - PDF document

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   Chair, Subcommittee on Indoor Air Quality, University of Nevada, Las Vegas Washington Department of Ecology  Occupational and Environmental Life Science
Chair, Committee on Environmental Microbiology, University of Maine
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 ith every breath, we inhale notonly life sustaining oxygen but alsodust, smoke, chemicals, microor-ganisms, and other particles and pollutants thatfloat in air. The average individual inhales about10 cubic meters of air each day, roughly the vol-ume of the inside of an elevator. Because peopletypically spend so much time indoors, poorindoor air quality (IAQ) can greatly affect indi-viduals and, more broadly, the public health andnational productivity. The US EnvironmentalProtection Agency (EPA) Science Advisory Boardrated indoor air pollutants, excepting radon, asthe third highest of 30 environmental risks, wellahead, of sixth ranked occupational exposures tochemicals. However, a shortage of IAQ researchleaves us with too ma

2 ny unknowns, even as moreand more occupa
ny unknowns, even as moreand more occupants of contaminated buildingsare reporting a variety of health symptoms thatthey attribute to poor IAQ. This also leads tohealth treatment, expensive remediation activi-Although poor IAQ is often viewed as a prob-lem peculiar to modern buildings, linkagesbetween air quality and disease have been knownfor centuries. Long before the germ theory of dis-ease led to recognition of pathogenic microorgan-isms, foul vapors were being linked withinfectious diseases. As our understanding of dis-ease increased, public health workers made pre-vention of pathogen transmission a centralconcern. Today, we understand that airbornetransmissions of pathogens, non-pathogenicorganisms, fragments of microbial cells, andbyproducts of microbial metabolism, collectivelyreferred to as Òbioaerosols,Ó can all cause seriousproblems. Contaminated indoor air thus has thepotential to harm public health and significantlyaffect the economy of the United States and other "     
 

  
 
      

     
 
  
    
    



  

 
 
  

   

 Although the Centers for Disease Control andPrevention (CDC) does not track either the typesor cases of illness attributable to bioaerosol expo-sure, bioaerosols are widely recognized to makewww.cdc.gov). Asthma affects anestimated 20 million Americans and costs the USeconomy more than $13 billion annually. TheAmerican Lung Association cites asthma as thesixth ranking chronic condition in the UnitedStates as well as the leading serious chronic illnessof children, with numbers of those affected risingeach year. In a recent report, the Institute ofwww.nap.eduÒthere is sufficient evidence of an associationbetween expo

3 sure to a damp indoor environmentand ast
sure to a damp indoor environmentand asthma symptoms in sensitized asthmaticpeopleÓ and that Òthere is a sufficient evidence ofan association between the presence of ÔmoldÕ(otherwise unspecified) in a damp indoor envi-ronment and asthma symptoms in sensitizedThe US Government Accountability Office(GAO) reports that an estimated 20 percent of allschools in the United States have indoor air prob-lems. Moreover, the general public is becomingincreasingly aware of IAQ problems. Over 3,500news reports related to mold toxicity have beenpublished since 2000, and some 10,000 moldrelated lawsuits are pending nationwide. Many ofthese lawsuits have been filed in regions with hot,humid climates, but construction defects andinferior maintenance practices can lead to build-ings with poor indoor air quality anywhere in thisor other countries.  
 
 

 



 
 
  

  
   



   
 
 


 
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  Bioaerosols are collections of airborne biologicalmaterials. Ubiquitous indoors and out, bioaerosolsin suspended, aerosolized liquid droplets typicallycontain microbes and cell fragments combinedwith byproducts of cellular metabolism. In addition,they may carry viruses, bacteria, and fungi that floaton dust particles along with cells and parts of cells.Although there are no recognized standard levelsfor bioaerosols in schools, offices, and residentialenvironments, several government agencies andprofessional organizations have published guid-ance documents that address bioaerosol concernsas an integral component of IAQ.!
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  Viruses require a living host for replication,meaning they cannot by themselves multiply onor in building materials. However, they can con-taminate interior spaces of manmade or naturalstructures such as occurred when Hantavirus infec-tions resulted among building occupants becauserodents had infested particular indoor environ-ments. More commonly, many viruses that infectthe respiratory tract spread from person to person,especially in crowded rooms with inadequate ven-poor IAQ. Coughing, laughing, and sneezing candischarge tens of thousands of virus filled dropletsinto the air and may readily spread illnesses inschools, offices, homes, or other settings. 

In contrast to viruses, bacteria and fungi willgrow, often to an alarming extent, on buildingmaterials if moisture is available. Background levelsof airborne bacteria and fungi change frequentlyinside buildings as a result of human activity,especially operation of mechanical air handlingsystems. Indeed, building conditions that allowexcessive growth of bacteria or fungi can lead tooccupants developing various specific medicalsymptoms or other complaints. Exposure indoorsto unusual bacterial populations generally attractsnotice when infectious disease results, such as the1976 outbreak of a serious respiratory diseaseamong attendees at a Legionnaire convention inPhiladelphia, later associated with a bacterial con-taminated ventilation system in the hotel wherethey had gathered. Endotoxin, a component ofsome bacteria, also can cause illnesses amongbuilding occupants who inhale this contaminant. - (!&!

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 Fungi, especially filamentous fungi called

5 mold, also lower air quality and cause p
mold, also lower air quality and cause publichealth problems though not typically as agents ofinfectious disease. Recently an IOM report statedthat Òthere is sufficient evidence of an associationbetween the presence of mold and bacteria indamp indoor environments and hypersensitivitypneumonitisÓ in sensitized persons. The IOM alsoreferred to a possible association between expo-sure to damp environments, the presence ofmolds, and an increased risk of lower respiratorytract illnesses in otherwise healthy children. Ofcourse, many fungi can play beneficial roles, forinstance, when they help to recycle organic mate-rial such as fallen trees and leaves and when theyare used in producing foods such as cheese, wine,and beer. However, when unwanted molds appearin ventilating systems or in other spaces withinoccupied buildings, exposures of occupants tothose molds can lead to serious problems.In general, the types and concentrations ofmold that affect IAQ are similar to those found inoutdoor air. However, background mold numbersmay shift whenever water accumulates in build-ings. Damage caused by floods, plumbing leaks,or roof and window leaks, and even climate andair conditioning related condensation can lead tolong term water related damage indoors. Oncewater accumulates in building materials and fur-nishings, it takes less than 72 hours for mold tobegin growing on those dampened surfaces.Hence, much of the information in this bookletaddresses mold contamination, which is a readilyrecognized and frequent consequence of elevatedindoor moisture levels.Building practices for commercial and publicstructures as well as residences have changedmarkedly in the past three decades, making manybuildings more prone to moisture problems thatlead to higher levels of microbial contaminants. Forexample, condensation often can occur in thosebuildings that ar

6 e tightened to improve energy effi-cienc
e tightened to improve energy effi-ciency when appropriate care is not given to venti-lation or how insulation is installed. Widely usedbuilding materials such as components made fromwood chips or walls consisting of paper coveredgypsum board are more sensitive to moisture thanis plaster. Poor understanding of moisture dynam-ics and careless building design and constructionlead to structures that are more susceptible to waterintrusion. Also, lack of good maintenance practicesin some buildings can lead to moisture buildupsthat, when left alone, can result in microbial con-tamination and higher levels of bioaerosols.   
 
  


  
 
       
 
  
    

   Moisture is the principal determinant of moldgrowth indoors. Different levels of moisture areneeded for growth of different molds. For instance,Aspergillusrequire little availablemoisture and often are found along drier areas ofwater damaged materials. Other molds that requirehigher levels of moisture include Stachybotrys. Not only are moldy surfaces aestheti-cally displeasing, they may require expensive repairand clean-up operations. Moreover, their presencecan also lead to illnesses and loss of productivitymold populations to those organisms associatedwith allergenic reactions or toxigenic byproducts,building occupants become more likely to reporthealth problems and to incur increased costs forhealth care. Costs for building maintenance andrepairs are also increased.& 
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* & Americans spend up to 90 percent of their timeindoors, where contaminants in bioaerosols aregenerally at higher levels than those found in out-door air. Frequently the duration of exposure tosuch contaminants also is greater indoors thanout. It is estimated that more than 30

7 percent ofbuildings in the United States
percent ofbuildings in the United States and WesternEurope have moisture problems serious enoughto promote microbial contamination of indoor air.Exposure to high levels of indoor moisture isassociated with upper respiratory symptoms,including higher incidence of coughing, wheez-ing, and asthma in sensitized persons, accordingto several large epidemiological studies cited bythe IOM. Additional case studies, cluster investi-gations, and clinical experience associate otherhealth complaints with living and working in /  
 




 
  
    
 

 
      

  

   

 damp buildings where mold and bacteria grow.Occupants of such damp buildings report a vari-ety of additional symptoms, including:Nasal congestion and runny noseWatery, burning eyesSore throat and hoarsenessDry, irritant-type coughTight chest, burning sensation, wheezing,shortness of breathNosebleeds, coughing blood (rare)Skin and mucous membrane irritation, rashesExhaustion, severe fatigueMemory and cognitive problemsGastrointestinal problems such as nausea,Health care professionals face the challengethat these symptoms are common and are associ-ated with many different disordeditions associated with exposure to viruses,bacteria, or fungi include infectious diseases, res-piratory disorders such as bronchitis and asthma,and other allergic, inflammatory, and toxicresponses. In some cases, evidence links thesedisorders to exposure to bioaerosols. For others,evidence is insufficient, reflecting the smallnumbers of exposed individuals whohave been carefully studied. Research that could establishcause and effect relationshipsbetween exposure to specificbiological agents and particular diseases awaitsseveral critical developments. These include avail-ability of methods to measure th

8 e spectrum ofpotential agents (mold spor
e spectrum ofpotential agents (mold spores and bacteria, theirfragments, volatile and semi volatile emissions,and allergen- or toxin-bearing particles) with ahigh degree of accuracy or of having alternativemethods to establish biomarkers that can linkexposure and effect. Most health effects attributa-ble to bioaerosol exposures last only briefly andtypically are reversible, particularly once mois-ture and consequent microbial contaminationproblems have been appropriately corrected.However, in some instances, health conse-quences may be seriirreversible.  
 
 


 


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    The choice of which methods to use when assess-ing microbial contaminated environments dependsupon the specific building type being investigatedand also on who occupies those buildings. Theclassical approach to assessing such microbialcontamination includes several basic steps:Gathering background informationbut not limited to, health of occupants (by ques-tionnaire or medical examination), bioaerosolpresence, excess moisture levels, microbialgrowth or unusual odors, location and status ofmicrobial growth, and means by which con-taminants may be disseminating through theFormulating and testingto deter-mine plausible reasons to explain how the build-ing became contaminated, with an emphasis on:Ñ the building environment (i.e., sources ofcontamination and moisture, routes bywhich contaminants are transferred withinÑ bioaerosol exposure data collected under asampling plan that is specific to what isbeing studied because collecting samplesfrom buildings demands a differentapproach than does assessing the healthand well being of occupants.Making recommendationslected, then implementing measures that reme-diate contaminants and will also preventrecu

9 rrences.Often a combination of building
rrences.Often a combination of building related factorsis responsible for poor IAQ. Teams involved inIAQ investigations typically include a mix of pro-fessionals, each with different skills to draw onwhen analyzing and resolving building relatedproblems. For instance, a medical professional orepidemiologist usually investigates healthaspects, while environmental microbiologists arecalled upon to investigate issues such as microbialecology within buildings. Additionally, engineers,industrial hygienists, and indoor environmental 2   
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 experts are trained to investigate other buildingrelated factors that contribute to water damageand result in microbial contamination, whereastoxicologists bring expert knowledge needed foranalyzing potentially toxic exposures. Ideally,investigators with varied backgrounds work as anintegrated team to study different aspects ofbuilding related problems, consulting extensivelywith one another and sharing information.Therefore, it is important that practitioners in dif-ferent fields be familiar with and appreciate theinformation, qualifications, and insights that otherdisciplines contribute.While indoor ÒdampnessÓ is associated withadverse health effects, in many cases the specificagents responsi-health outcomeshave not beentified. Publishedreports often fail todemonstrate directlinks betweenexposures ofbuilding occupants to microorganisms with thespecific respiratory health effects that those occu-pants describe. This failure to provide definitiveproof that poor IAQ causes particular illnesses maybe related to several factors, including inadequatemethods for assessing exposures of occupants tor

10 elevant microorganisms and their product
elevant microorganisms and their products, and alack of understanding whether particular microor-ganisms are responsible for causing specific adversehealth effects. Given the current state of knowledge,investigations of environments suspected of beingcontaminated with microbes should focus on con-ditions that contribute to the growth of those organ-isms (i.e., moisture accumulation and moistureinfiltration) and also the means to prevent theseconditions from occurring.Investigations of mold related problems oftenrely upon sampling techniques to determine moldgrowth in the indoor environment as an indirectestimate of the occupantsÕ exposure to thosemolds. There are disadvantages for each samplingmethod, meaning no one method is capable offully characterizing building ecology or occupantexposure. Fungal growth entails a dynamic suc-cession of events that vary over time and withenvironmental conditions. Although differentsampling methods may yield abundant data, eachsuch method can yield only a ÒsnapshotÓ of thisdynamic process, particularly when circum-stances force investigators to collect limited num-bers of samples. A strategy to more accuratelycharacterize indoor fungal contamination mayrequire collecting large numbers of samples overextended periods, but such approaches inevitablyprove more costly and might not even prove morevaluable when it comes to defining occupant expo- (


 
 


 
  
 
 
 


 

  



  sure. In short, environmental sampling does notalways provide clear explanations for poor IAQ orfor the illnesses that it is suspected of causing.Interpreting sample data presents a challengeto investigators. Currently no numeric standardsestablish acceptable concentrations for airbornefungi in non-manufacturing work environments. In

11 1999, the American Conference of Governm
1999, the American Conference of GovernmentalIndustrial Hygienists (ACGIH) stated that Ònoconsensus health-based guidelines exist, nor areany likely to be developed, until more data areavailable on dose-response relationships for spe-cific agents and health outcomes, and more base-line data have been collected from randomlyselected environments.Ó In the absence of numer-ical guidelines, those interpreting bioaerosol datarely upon: a) indoor/outdoor ratios of fungal con-centrations, b) comparison of species collectedindoors and out, and c) the presence of indicatorspecies (i.e. presence of fungal types that arisebecause of excess moisture).Perhaps the most useful overall tool availableto building owners and operators and, more gen-erally, the public is to conduct thorough inspec-tions of buildings for the presence of visible moldand excess water. However, additional factorsneed to be considered, such as the presence ofhidden mold and its potential impact on a specif-ic indoor environment. Overall, decisions derivedfrom an investigation should be based upon thebest data possible, along with experience, expertopinion, specialized methods, and also commonsense to interpret information and to design con-trol and remediation strategies. 5 



 
 
 
  
 

   

 




 
 
   

   The primary goal of remediation is to restoreindoor spaces to their pre-contamination condi-tions. Defining ÒcleanÓ and determining at whatpoint a remediation project can be judged suc-cessful are subjects of considerable debate. Therecently published Standard and Reference Guidefor Professional Mold Remediation(Institute ofInspection, Cleaning, and Restoration Certification,2003) defines a clean environment as Òan indoorenvironment that may have se

12 ttled spores, fungalfragments or traces
ttled spores, fungalfragments or traces of actual growth, whose iden-tity, location, and quantity are reflective of a nor-mal fungal ecology for a similar environment.ÓUnder any circumstances, parties should agree tothe measure of ÒcleanÓ that will be used to gaugethe success of a remediation effort prior to begin-ning the corrective process.The underlying principles of remediation aresimple and straightforward, and they include:Identify and correct the moisture problem;Protect the health and safety of workers andControl mold contamination as close to itssource as possible (prevent dispersion);Remove mold contaminated porous materials(e.g., upholstered furnishings, carpets, anddrapery) that cannot be salvaged;Clean nonporous materials and surfaces;Remove remaining dust;Prevent reentry of moisture into the environ-Rebuild using moisture safe structures, mate-rials, and systems that can serve under pre-vailing environmental conditions withoutchemical or biological deterioration.In practice, professionals have several optionsfor removing molds or other contaminants, asdetermined by specific building type, climate,degree of contamination, and risks that those meth-ods may pose to building occupants, including con-cerns about their health and sense of wellbeing.The best defense against excessive mold inindoor environments is to prevent microbialgrowth in or on building materials and furnish-ings. Within the home and office, some simplesteps taken early can effectively reduce healthproblems related to indoor microbial contamina-tion. They include:Maintain relative humidity below 60 percentwithin buildings;Use an air conditioner or a dehumidifier dur-ing humid months and maintain it properly;   
 

    



  Provide adequate ventilation in buildings,including exhaust fans in kitchens an

13 d bath-rooms;Keep bathroom and kitchen s
d bath-rooms;Keep bathroom and kitchen surfaces cleanand regularly treat them with disinfectingproducts;Do not place carpeting in bathrooms, base-ments, or other areas where humidity is high;Remove or replace carpets and upholstery ifthey cannot be dried out immediately afterbecoming wet.
 


  
  
 




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Studies of both the relationship between IAQand microbial contamination and of the impactof poor IAQ on occupants are far from beingdefinitive, making research needs in this fieldbroad ranging and multidisciplinary; they includeMore objective, accurate methods, includingstandardized inspection protocols to assessthe risk of exposure to various conditionsand microbial agents.IAQ and its impact on health commonly referto exposure indicators such as Òdamp hous-ing,Ó Òwater damage,Ó and Òvisible mold.ÓHowever, those investigators need to draw onobjective methods for measuring these indica-tors instead of methods based on simple, visu-al observations of building conditions that areneither well substantiated nor standardized. Better means for characterizing moisturerelated pollutants, including microbial andchemical emissions, and for estimating theirimportance as exposure agents.Availabledirect methods for meas

14 uring and further char-acterizing pollut
uring and further char-acterizing pollutants associated with excessmoisture in buildings do not provide reliablereadings. One major problem is that cur-rent methods typically provide onlyshort-term measurements, whereasexpected to yield more reliablefindings. More accurate analysistechniques are also needed.  :
  
 

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 Better understanding of how materialsbehave under environmental conditionssuch as high humidity, how different mate-rials interact, and how different microbesinteract among themselves and with differ-contractors and consumers are seldom suffi-ciently tested for their moisture related physi-cal properties or their biological and chemicalactivities. Depending on what materials arebeing used, high moisture levels may lead toincreased emissions due to microbial andchemical deterioration. The materials onwhich microorganisms are growing can affectthe byproducts that they produce and may, forexample, lead fungi to release particular toxinsBetter understanding of what leads toadverse health effects and whether they willbe readily reversible or chronic.Most pub-lished studies rely on data collected by meansof questionnaires distributed to building occu-pants for estimating risk to them of adversehealth effects from exposures to poor IAQ.More objective methods to estimate health out-comes should be developed, including directclinical diagnostic methods and indirect bio-marker based methods. In addition, studies inwhich animals are exposed to comparableIAQs could lead to a better understanding ofhow different periods of exposure to dampnessmay affect the likelihood of developing adversehealth effects. Improved efforts to integrate scientificinformation with practical efforts to preventand resolve problems arising from expo-sures to excess moisture.Those who are co

15 n-ducting private and public assessments
n-ducting private and public assessments of IAQshould be encouraged to make better use ofscientific findings. Remedial actions at specificbuilding sites should include reviews of build-ing codes and agreements to modify themwhere appropriate, as well as efforts to educatebuilding professionals, owners, and occupants.Several US government agencies sponsorresearch addressing IAQ issues, although the focusof these efforts is often not directed specifically atproblems with bioaerosols. The CDC sponsorsgrants and cooperative agreements for research inthe areas of environmental health, epidemiology,Health (NIOSH) within CDC sponsors research onhealth issues affecting workers, with prevention ofdisease being the over arching goal of thoseresearch programs. NIOSH also sponsors studiesto identify occupational populations at risk, todevelop methods for measuring exposures to haz-ards and detecting adverse health effects, to deter-mine the prevalence and incidence of occupationalhazards, to understand the etiology of occupation-   
 

 
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   al diseases and injuries, and to reduce or eliminatesuch exposures. Grants managed by the USDepartment of Housing and Urban Development(HUD) include Òhealthy homesÓ projects forwhich mold and moisture could be a focus. TheNational Institutes of Health (NIH) funds a widevariety of health related studies, some of whichgauge environmental effects on health, particular-ly through the National Institute of EnvironmentalHealth Sciences (NIEHS). Moreover, the USEnvironmental Protection Agency (EPA) sponsorsresearch on childrenÕs health that includes investi-gations of adverse environmental effects. During the past decade, excess moisture andmold related IAQ issues have attracted intensiveattention from the public and the news media inFinland and other Nordic c

16 ountries. In 1995, arandom sample of 450
ountries. In 1995, arandom sample of 450 Finnish houses showedthat over half of them needed repair due to prob-lems from excess moisture. Subsequent in-depthanalysis showed that many occupants of thosemoisture damaged homes reported various healthsymptoms, including respiratory infections aswell as other respiratory or more general symp-toms. These findings underscore the need formore scientific and practical information onexcess moisture related phenomena in buildings,consequent exposures to microbiological andchemical pollutants, and adverse health effectsamong building occupants. An extensive studyprogram in Finland demonstrated that the major-ity of mold related health consequences appear tobe reversible following repair to moisture dam-aged buildings.  &
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Determining the quality of indoor air, assess-ing microbial contributions to compromised airquality, and establishing protocols either toimprove air quality or to prevent it from becom-ing compromised are complex challenges.Meeting these challenges will require multidisci-plinary approaches involving a wide range of pro-fessionals working in academia, government,health care, and the building industry. New edu-cational programs are essential for designing andimplementing multidisciplinary approaches need-ed to address those challenges. Educational pro-increase, through continuing education, thecapacity of microbiologists to conductresearch, monitoring, remediation efforts, andprevention programs;support certification programs for industrialhygienists and other professionals who moni-tor and remediate indoor environments;educate undergraduate and graduate studentsin biological, environmental, and engineeringprograms by augmenting course curricula; -   
 
 

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 inform medical and occupational he

17 alth pro-fessionals about the diverse ro
alth pro-fessionals about the diverse roles and impact ofmicroorganisms on IAQ; and inform professionals in building design, con-struction, and maintenance on causes of andsolutions to compromised air quality. !
Create an interagency committee, which wouldinclude experts from agencies such as EPA,NIOSH, CDC, NIH, and NIEHS, plus non-governmental advisors with appropriateexpertise for assessing IAQ related issues;Determine and then provide the levels ofresearch and education funding needed to sig-nificantly reduce and prevent IAQ healtheffects;Adopt standardized methods for collectingdata and reporting findings;Define and compile appropriate databasesneeded to establish appropriate IAQ policies,particularly as related to microbial pathogens;Identify and develop appropriate science basedcare personnel, and building professionalsabout the best available methods to assess, con-trol, prevent, and remediate microbial contam-ination in indoor environments; and Develop interagency collaborations to addressfundamental research gaps regarding indoormold contamination, such as, but not limited to:Ñ Improving the understanding of the ecologyof mold and other microorganisms.Ñ Developing an understanding of the etiologyof mold and other microbial related illnesses.Ñ Studying the potential synergistic effectsof mold, other microorganisms, and other   
 

 
      
     
 

 
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   . 2004. Introduction to the BiologicallyDerived Airborne Contaminants. 2004 TLVsbased on the Documentation of the ThresholdLimit Values for Chemical Substances and PhysicalAgents & Biological Exposure Indices. ACGIHWorldwide, Cincinnati OHBurge, H.A. 1995. Bioaerosols in the residential envi-ronment, pp. 579-593. C.S. Cox and C.M. Wates(eds.), Bioaeroso

18 ls Handbook. Lewis Publishers,London, Un
ls Handbook. Lewis Publishers,London, United Kingdom.Buttner, M.P., K. Willeke, and S. Grinshpun. 2002.Sampling and Analysis of Airborne Microorganisms,pp. 814-826. C.J. Hurst, G. Knudsen, M. McInerney,M.V. Walter, and L.D. Stetzenbach (eds.), Manual ofEnvironmental Microbiology, 2edition, ASM Press,Washington, DC.Garrett, M.H., P.R. Rayment, M.A. Hooper, M.J.Abramson, and B.M. Hooper. 1998. Indoor airbornefungal spores, house dampness and associations withenvironmental factors and respiratory health in chil-dren. Clinical Exposure and Allergy. Volume 28, pp.Harrison, J., C.A.C. Pickering, E.B. Faragher, P.K.C.Austwick, S.A. Little, and L. Lawton. 1992. An investi-gation of the relationship between microbial and par-ticulate indoor air pollution and the sick buildingsyndrome. Respiratory Medicine. Volume 86, pp. 225-Institute of Medicine. 2004. Damp Indoor Spaces andHealth. The National Academy Press, Washington, DC.Macher, J.M. 1999. Bioaerosols: Assessment andControl. American Conference of GovernmentalIndustrial Hygienists (ACGIH), Cincinnati, OH.Miller, J.D. 1992. Fungi as contaminants of indoor air.Atmospheric Environment. Volume 26A, pp. 2163-Rylander, R., and R. Etzel. 1999. Introduction and sum-mary: workshop on childrenÕs health and indoor moldexposure. Environmental Health Perspectives. Volume107, pp. 465-468. Stetzenbach, L.D., and M.P. Buttner. 2000. AirborneMicroorganisms and Indoor Air Quality, pp. 116-125.J. Lederberg (ed.), Encyclopedia of Microbiology, 2edition. Academic Press, San Diego, CA.U.S. EPA. 2002. A Brief Guide to Mold, Moisture, andYour Home. EPA 402-K-02-003. Washington, DC.Wickman, M., S. Gravesen, S.L. Nordvall, G.Pershagen, and J. Sundell. 1992. Indoor viable dust-bound micro-fungi in relation to residential character-istics, living habits, and symptoms in atopic andcontrol children. Journal of Allerg

19 y and ClinicalImmunology. Volume 89, pp.
y and ClinicalImmunology. Volume 89, pp. 752-759.Yang, C.S., and E. Johanning. 2002. C. J. Hurst, R.L.Crawford, G. Knudsen, M. McInerney, and L.D.Stetzenbach, (eds.), Manual of EnvironmentalMicrobiology, 2edition, ASM Press, Washington, DC.For more detailed information on remediationstrategies and techniques consult the current existingguidance documents including: New York CityDepartment of Health Guidelines on the Assessmentand Remediation of Fungi in Indoor Environments(2000), American Conference of GovernmentalBioaerosols:Assessment and Control(1999), U.S. EnvironmentalProtection Agency Mold Remediation in Schools andCommercial Buildings(2001), and the Institute ofStandard and Reference Guide for ProfessionalMold Remediation / )! 

 Ñsingle celled microorganisms with varyingnutritional and physical/chemical requirements thatallows them to colonize and grow in the environment.BioaerosolÑa collection of airborne biological materi-al that may include bacterial cells, fungal spores, virusparticles, microbial fragments, skin cells and other par-ÑAn asexually produced fungal spore, formedon a conidiophore.ConidiophoresÑSpecialized fungal threadlike fila-ments forming the mycelium of a fungus that producesÑthe study of the relationships betweenorganisms and their environment.Ña heat-stable complex of the outer mem-brane of some bacteria that can elicit adverse healtheffects in exposed people.Ñthe branch of medicine that dealswith the study of the causes, distribution, and controlof disease in populations.Ñthe study of the causes of a disease.Ñmicroorganisms that are non-photosyntheticand utilize organic materials as nutrients for growthand may produce toxins or cause allergic reactionswhen growing in water damaged buildings.ÑAny of the threadlike filaments forming themycelium of a fungus.Ñthe condition of the a

20 iroutdoors and inside buildings with res
iroutdoors and inside buildings with respect to the levelof biological, chemical, and particulate material. IAQ isalso known as Indoor Environmental Quality (IEQ)when additional factors are considered such as lighting,temperature, humidity, and draft.Industrial HygienistÑa specialist in the science ofhealth promotion and preservation in the workplaceand community. Microbial pathogensÑmicroorganisms which causeadverse health effects.Ñfilamentous fungi classified by their growthstructures and categorized by their nutritional, temper-ature, and moisture requirements.ÑThe vegetative part of a fungus, consistingof a mass of branching, threadlike hyphae.Ñchemical produced as a natural productof fungal metabolism that is toxigenic to other organ-Ñthe removal of biologically contaminat-ed building materials following water damage andresultant growth of contaminant organisms.SporeÑA small, usually single-celled reproductivebody that is highly resistant to desiccation and heat andis capable of growing into a new organism, produced bycertain bacteria, fungi, algae, and non-flowering plants.ToxicologistÑthe study of the nature, effects, anddetection of poisons and the treatment of poisoning.ToxigenicÑa chemical which will damage organisms.VirusÑa small acellular biological particle that hasnucleic acid, but cannot replicate without an appropri-ate living host cell. &!!
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