1、10.1CHAPTER 10INDOOR ENVIRONMENTAL HEALTHBackground 10.1Descriptions of Selected Health Sciences 10.3Hazard Recognition, Analysis, and Control . 10.4AIRBORNE CONTAMINANTS 10.4Particles . 10.4Gaseous Contaminants 10.10Outdoor Air Ventilation and Health. 10.16PHYSICAL AGENTS 10.17Thermal Environment.
2、10.17Electrical Hazards 10.19Mechanical Energies 10.19Electromagnetic Radiation. 10.22Ergonomics. 10.24NDOOR environmental health comprises those aspects of hu-I man health and disease that are determined by factors in theindoor environment. It also refers to the theory and practice ofassessing and
3、controlling factors in the indoor environment that canpotentially affect health. The practice of indoor environmentalhealth requires consideration of chemical, biological, physical andergonomic hazards.Diseases are caused by genetics and exposures. Despite a hugeinvestment in DNA research in recent
4、decades, few diseases can besolely explained by our genes. An interaction between genes andenvironmental exposures is needed, and understanding indoorenvironmental exposures is essential in this respect. Over a 70-yearlifespan in a developed region, indoor air (in homes, schools, daycares, offices,
5、shops, etc.) constitutes around 65% of the totallifetime exposure (in mass), whereas air in industry, outdoor air, airduring transportation, food, and liquid makes up the rest. For themost vulnerable population, newborns, indoor air in homes makesup around 80% of the exposure.It is essential for eng
6、ineers to understand the fundamentals ofindoor environmental health because the design, operation, andmaintenance of buildings and their HVAC systems significantlyaffect the health of building occupants. In many cases, buildings andsystems can be designed and operated to reduce the exposure ofoccupa
7、nts to potential hazards. Unfortunately, neglecting to considerindoor environmental health can lead to conditions that create orworsen those hazards.This chapter provides general background information and intro-duces important concepts of hazard recognition, analysis, and con-trol. It also presents
8、 information on specific hazards, and describessources of exposure to each hazard, potential health effects, relevantexposure standards and guidelines, and methods to control expo-sure.This chapter is introductory in nature, and indoor environmentalhealth is a very broad and dynamic field. Thus, des
9、criptions ofpotential hazards (and especially their controls) presented are not acomprehensive, state-of-the-art review. Additional detail is availableon many important topics in other ASHRAE Handbook chapters,including Chapter 9, Thermal Comfort, of this volumeChapter 11, Air Contaminants, of this
10、volumeChapter 12, Odors, of this volumeChapter 16, Ventilation and Infiltration, of this volumeChapter 29, Air Cleaners for Particulate Contaminants, of the2012 ASHRAE HandbookHVAC Systems and EquipmentChapter 31, Ventilation of the Industrial Environment, of the 2011ASHRAE HandbookHVAC Applications
11、Chapter 46, Control of Gaseous Indoor Air Contaminants, of the2011 ASHRAE HandbookHVAC ApplicationsOther important sources of information from ASHRAE includethe building ventilation and related requirements in Standards 62.1and 62.2. Additional details are available from governmental andprivate sour
12、ces, including the U.S. Department of Health andHuman Services Centers for Disease Control and Prevention, U.S.Environmental Protection Agency, Occupational Safety and HealthAdministration, American Conference of Governmental IndustrialHygienists, National Institute for Occupational Safety and Healt
13、h,parallel institutions in other countries, and the World Health Orga-nization.BACKGROUNDEvaluation of exposure incidents and laboratory studies withhumans and animals have generated reasonable consensus on safeand unsafe workplace exposures for about 1000 chemicals and par-ticles. Consequently, man
14、y countries regulate exposures of workersto these agents. However, chemical and dust contaminant concentra-tions that meet occupational health criteria usually exceed levelsacceptable to occupants in nonindustrial spaces such as offices,schools, and residences, where exposures often last longer and
15、mayinvolve mixtures of many contaminants and a less robust population(e.g., infants, the elderly, the infirm) (NAS 1981).The generally accepted definition of health is that in the constitu-tion of the World Health Organization (WHO): “Health is a state ofcomplete physical, mental, and social well-be
16、ing and not merely theabsence of disease or infirmity.”Another, more narrowly focused definition of health by theAmerican Thoracic Society (ATS 1999) takes into account broader,societal decision-making processes in defining what constitutes anadverse health effect of air pollution. Key points of the
17、 ATS defini-tion of adverse effects are as follows:Biomarkers, or biological indicators (e.g., in blood, exhaled air,sputum) of environmental effects. Because few markers have yetbeen sufficiently validated for use in defining thresholds, not allchanges in biomarkers related to air pollution should
18、be consideredadverse effects.Quality of life. Adverse effects of air pollution can range fromwatering, stinging eyes to cardiopulmonary symptoms, and evenpsychiatric conditions.Physiological impact. Physical effects of pollution can be transi-tory or permanent, and appear alone or accompanied by oth
19、ersymptoms. The ATS minimum requirement for considering pollu-tion to have an adverse effect is reversible damage accompaniedby other symptoms (reversible damage alone is not sufficient).Also, effects such as developmental damage to lungs, or exacer-bation of age-related decay in function, must be c
20、onsidered.The preparation of this chapter is assigned to the Environmental HealthCommittee.10.2 2013 ASHRAE HandbookFundamentalsSymptoms. Not all increased occurrences of symptoms are con-sidered adverse effects of air pollution: only those diminishing anindividuals quality of life or changing a pat
21、ients clinical statusshould be considered adverse.Clinical outcomes. Detectable effects of air pollution on clinicaltests should be considered adverse.Mortality. Any effect on mortality should be judged adverse.Population health versus individual risk. Any change in therisk of an exposed population
22、should be considered adverse, evenif there is no immediate, outright illness.Definitions of comfort vary. Comfort encompasses perception ofthe environment (e.g., hot/cold, humid/dry, noisy/quiet, bright/dark)and a value rating of affective implications (e.g., too hot, too cold).Rohles et al. (1989)
23、noted that acceptability may represent a moreuseful concept of evaluating occupant response, because it allowsprogression toward a concrete goal. Acceptability is the foundationof a number of standards covering thermal comfort and acoustics.Nevertheless, acceptability varies between climatic regions
24、 and cul-tures, and may change over time as expectations change.Concern about the health effects associated with indoor air datesback several hundred years, and has increased dramatically in recentdecades. During the 1970s and 1980s, this attention was mainly aresult of concerns about radon and lung
25、 cancer, and about increasedreporting by building occupants of complaints about poor healthassociated with exposure to indoor air sick building syndrome(SBS). More recently, interest has largely focused on asthma,allergies, and airway infections.SBS encompasses a number of adverse health symptoms re
26、latedto occupancy in a “sick” building or room, including mucosal irrita-tion, fatigue, headache, and, occasionally, lower respiratory symp-toms, and nausea. Large field studies (EPA 2012; Skov and Valbjorn1987; Sundell et al. 1994) have shed light on the causes. Widespreadoccurrence of these sympto
27、ms prompted the World Health Orga-nization to classify SBS symptoms (WHO 1983):General symptoms, such as headache, tiredness, nauseaMucous membrane symptoms in the nose, eyes, or throat, includ-ing coughing, sensations of drynessSkin symptoms: redness, itching, on upper body partsSick building syndr
28、ome is characterized by an absence of routinephysical signs and clinical laboratory abnormalities with regard tosensory irritation and neurotoxic symptoms, while skin symptomsoften can be objectively verified. Some investigations have sought tocorrelate SBS symptoms with reduced neurological and phy
29、siologi-cal performance. In controlled studies, SBS symptoms can reduceperformance in susceptible individuals (Mlhave et al. 1986).Building-related illnesses (BRIs) have similar symptoms, butinclude physical signs and abnormalities that can be more easilyclinically identified (e.g., hypersensitivity
30、 illnesses, including hy-persensitivity pneumonitis, humidifier fever, asthma, and allergicrhinitis).Some illnesses associated with exposure in indoor environmentsare listed in Table 1. Laboratory testing and development of link-ages should be performed under direction of a qualified health careprof
31、essional.Table 1 Selected Illnesses Related to Exposure in BuildingsIllness Physical Examination Laboratory Testing Linkage Causes/ExposuresAllergic rhinitis Stuffy/runny nose, postnasal drip, pale or erythematous mucosaAnterior and posterior rhino-manometry, acoustic rhinome-try, nasal lavage, biop
32、sy, rhinoscopy, RAST or skin prick testingImmunologic skin prick or RAST testingPollen and dust mites are com-mon examplesAsthma Coughing, wheezing, episodic dyspnea, wheezing on examination, chest tightness, temporal pattern at workSpirometry peak expiratory flow diary, methacholine challenge, exha
33、led NOImmunology testing: skin prick or RAST; physiology testing*Pet dander, mold, environmental tobacco smoke, and dust mites are common examplesOrganic dust toxic syndromeCough, dyspnea, chest tight-ness, feverishnessDLCO, TLC Temporal pattern related to work Gram-negative bacteria or endotoxinHyp
34、ersensitivity pneumonitisCough, dyspnea, myalgia, weakness, rales, clubbing, feverishnessDLCO, FVC, TLC, CXR, lung biopsyImmunology testing: IgG anti-body to agents present, chal-lenge testing, physiology testing (in acute forms): spirometry, DLCOCausative agents include thermophilic actinomycetes;
35、molds; mixed amoebae, fungi, and bacteria; avian proteins; certain metals and chemicalsContact dermatitis Dry skin, itching, scaling skin Scaling, rash, eczema, biopsy Patch testing; allergy testingUrticaria (hives) Multiple swollen raised itchy areas of skinInspection, biopsy Provocation testing Sk
36、in irritation, foods, heat/cold, direct pressure, sunlight, drugs Eye irritation Eye itching, irritation, drynessTear-film break-up time, con-junctival staining (fluorescein)Temporal pattern VOCs and particulate matter are common examplesNasal irritation Stuffy, congested nose, rhinitisAcoustic rhin
37、ometry, posterior and anterior rhinomanometry, nasal lavage, nasal biopsyTemporal pattern VOCs and particulate matter are common examplesCentral nervous system symptomsHeadache, fatigue, irritability, difficulty concentratingNeuropsychological testing Temporal pattern (epidemiol-ogy)Chemical compoun
38、ds, noise, lighting, work stress, and carbon monoxide are common examplesLegionnaires disease, Aspergillosis, Pseudomonas infectionPneumonia, high fever, organ dysfunctionEnvironmental surveillance (water system monitoring), Legionella pneumophila iden-tification from patientOrganism isolated from p
39、atient and source; immunology testingLegionella (and other microorganism)-contaminated aerosols from water sourcesPontiac fever Non-pneumonic flulike illnessEnvironmental surveillance (water system monitoring)Range of microorganisms, chemicals*(1) 10% decrement in FEV1across workday,(2) peak flow ch
40、anges suggestive of work relatedness(3) methacholine reactivity resolving after six weeks away from exposureRAST = radio allergen sorbent testDLCO = single breath carbon monoxide diffusingcapacityFVC = forced vital capacityTLC = total lung capacityCXR = chest X-rayIgG = class G immune globulinsFEV1=
41、 forced expiratory volume in the first secondIndoor Environmental Health 10.3DESCRIPTIONS OF SELECTED HEALTH SCIENCESThe study of health effects in indoor environments includes anumber of scientific disciplines. A few are briefly described here tofurther the engineers understanding of which health s
42、ciences maybe applicable to a given environmental health problem.Epidemiology and BiostatisticsEpidemiology studies the causes, distribution, and control of dis-ease in a population. It represents the application of quantitativemethods to evaluate health-related events and effects. Epidemiologyis tr
43、aditionally subdivided into observational and analytical compo-nents; the focus may be descriptive, or may attempt to identifycausal relationships. Some classical criteria for determining causalrelationships in epidemiology are consistency, temporality, plausi-bility, specificity, strength of associ
44、ation, and dose/response.Observational epidemiology studies are generally performedwith a defined group of interest because of a specific exposure orrisk factor. A control group is selected on the basis of similar crite-ria, but without the exposure or risk factor present. A prospectivestudy (cohort
45、 study) consists of observations of a specific groupover a long time.Examples of epidemiological investigations are cross-sectional,experimental, and case-control studies. Observations conducted atone point in time are considered cross-sectional studies. In experi-mental studies, individuals are sel
46、ectively exposed to a specificagent or condition. These studies are performed with the consent ofthe participants unless the condition is part of the usual workingcondition and it is known to be harmless. Control groups must beobserved in parallel. Case-control studies are conducted by identi-fying
47、individuals with the condition of interest and comparing fac-tors of interest in individuals without that condition.Industrial, Occupational, and Environmental Medicine or HygieneThese sciences are about anticipating, recognizing, evaluating,and controlling conditions that may cause illness or injur
48、y. Impor-tant aspects include identifying toxic exposures and physical stress-ors, determining methods for collecting and analyzing contaminantsamples, evaluating measurement results, and developing controlmeasures.MicrobiologyBuildings are more than inanimate physical entities, masses ofinert mater
49、ial that remain relatively stable over time. The building,its occupants and contents, and its surroundings constitute adynamic triad in which all elements affect each other. In fact, abuilding is a dynamic combination of physical, chemical, andbiological dimensions. Buildings can be described and understoodas complex systems. Some new approaches, based on the frame-works, tools, and methods used by ecologists to understand ecosys-tems, can help engineers understand the processes and microbescontinually occurring indoors and how they affect the buildingsinhabitants, durability
