the psychological effects indoor airpollution*...m. j. colligan domestic and nonindustrial...

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THE PSYCHOLOGICALEFFECTS OF INDOORAIR POLLUTION*

MICHAEL J. COLLIGAN, Ph.D.

Division of Biomedical and Behavioral ScienceNational Institute for Occupational Safety and Health

Cincinnati, Ohio

R ene Dubos1 has noted that the modern environment threatenshuman life in at least two ways: it contains elements that are noxious

or outright toxic and it changes so rapidly and continuously as to prohibithuman adaptation. The effects of the former might be expected to be rela-tively direct and specific, resulting in clearly identifiable biological andpsychological consequences in response to environmental stressors. Usinga dose-response model, elements such as noise, crowding, temperatureextremes, isolation, and chemical exposures have been examined in anattempt to ascertain their impact on certain aspects of individual func-tioning and adjustment.The consequences of the second type of threat are more diffuse and less

specific. Industrialization and concomitant technological change havedrastically altered the complexion of our environment, influencing us inways we have not yet begun to understand. As a result, we may experiencesubtle fluctuations in our customary physiological, psychological, andperformance functions for which we have no obvious explanation or justi-fication. Hans Selye2 had defined this nonspecific response to environ-mental stress as the general adaptation syndrome, producing a similarlynondescript psychological state best defined as feeling "blah" or "out ofsorts." The basic notion is that, above and beyond the idiosyncratic effectsproduced by a specific stress or challenge, there exists a general bodilyresponse to injury as such, and the latter reaction is independent of the

* Presented as part of a Symposium on Health Aspects ofIndoor Air Pollution sponsored by theCommittee on Public Health of the New York Academy of Medicine and held at the Academy May 28and 29, 1981.Address for reprint requests; NIOSH, 4676 Columbia Parkway, Cincinnati, Ohio 45226

Bull. N.Y. Acad. Med.

EFFECTS 1015

particular characteristics of the stressor. Selye has described his study ofthis phenomenon as "the pharmacology of dirt." Nevertheless, it is impor-tant to realize that the experience of a general malaise is as legitimate andserious a concern to an environmentally stressed individual as the moresalient and specific response to particular chemical pollutants. Further,an individual's attempt to understand and to make sense of these nonspe-cific symptoms in the absence of a clearly identifiable cause has importantconsequences for the way an individual reacts to his environment.

Following a brief review of the literature regarding the specific psycho-logical and behavioral effects of air pollution, I shall attempt to discuss airpollution as a general source of stress, exerting diffuse and nonspecificeffects on an individual. Finally, I should like to examine the psychologi-cal processes whereby an individual under stress, regardless of its origin,might come to attribute his discomfort, rightly or wrongly, to contami-nants in the environment.

SPECIFICALLY BEHAVIORAL AND PSYCHOLOGICAL EFFECTS OFINDOOR AIR POLLUTANTS

Research into the specific psychological and behavioral responses toparticular indoor pollutants is sparse.3 Using a Pavlovian conditioningparadigm, Russian investigators have reported that low-level exposures tosuch agents as nitrogen dioxide and sulfur dioxide may alter human visu-al processes (e.g., darkness adaptation and brightness sensitivity), length-en reaction time, and increase dyssynchronization of alpha rhythms.4Although empirical tests have not been made of this hypothesis, Evans3suggests that the irritating effects of oxidants and carbon monoxide re-sulting in eye discomfort, labored respiration, and headaches mayheighten anxiety and depression, producing an overall decline in moodstate and psychological functioning. Indirect support for this proposal ispresented by Strahilevitz et al.,- who report moderate positive correlations(0.22,0.20) between ambient nitrogen dioxide levels in the St. Louis areaand admissions of patients to psychiatric hospitals with alcoholic andorganic brain syndromes.

Ozone, a byproduct of the operation of electrical motors and such officeequipment as photocopying machines, has received a cursory examina-tion in terms of its probable psychological effects. The current govern-ment permissible exposure limit is 0.1 ppm. for industrial settings.6

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M. J. COLLIGAN

Domestic and nonindustrial concentrations are normally in the 0.02 to0.03 ppm. range.7 Exposure concentrations beyond the 0.1 ppm. levelare correlated with symptoms of dryness of upper respiratory tract,throat and nose irritation, coughing, substernal pressure, and fatigue.Drowsiness and difficulty concentrating may also be evident.6 Lagerwerff8exposed subjects to ozone concentrations ranging from 0.2 to 0.5 ppm.for periods offrom three to six hours and produced considerable decreas-es in visual acuity under low illumination. Peripheral vision and photopic(light adapted) acuity were either unimpaired or improved by ozoneexposures, suggesting differential effects upon the rods and cones of theretina. Unsolicited subjective complaints expressed by participants inthis study included burning sensations in the eyes, tightness of the facialskin as after prolonged sunbathing, and feelings of fatigue coupled withinability to concentrate. Lagerwerff also reported obvious lethargy inmany of his subjects, persisting for as long as a day or two after the expo-sure period. Whether or not feelings of lethargy and inability to concen-trate reported by ozone-exposed subjects actually result in decrements inmental performance is unclear. Hore and Gibson,9 for example, admin-istered the Lorge-Thorndike Intelligence Test to subjects both before andduring exposure to ozone at concentrations of 0.2 ppm. and found nodifference in their scores relative to those obtained from correspondingcontrol and placebo groups. To control for possible effects of anxiety onintelligence test performance, the three groups were given standard anx-iety tests prior to the ozone exposure and baseline differences adjustedfor. No measures of anxiety were obtained in response to the ozone' expo-sure, however, nor is it possible with this experimental design to deter-mine what effects treatment-induced changes in anxiety level may havehad on intelligence test performance at retest. Obviously, more researchis needed along these lines.

Perhaps the most pervasive indoor air pollutant is carbon mon-oxide.10'11 In addition to seepage from the outside from auto exhaust,indoor sources of carbon monoxide involve fossil fueled heating and fur-nace emissions and cigarette smoke.1213 Yocum et al.14 compared indoorlevels of carbon monoxide obtained from both gas and coal-heated singlefamily dwellings against outdoor concentrations, and found that indoorlevels ranged from 0.76-6.02 ppm. and almost constantly exceeded thosefound outside.The present federal standard for carbon monoxide is 50 ppm., al-

though The National Institute of Occupational Safety and Health has


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recommended that the standard be lowered to 35 ppm. with a ceiling of200 ppm. This latter value would limit carboxyhemoglobin formation to5% in a nonsmoker engaged in sedentary activity.6

Typical signs or symptoms of acute carbon monoxide poisoning arewell known and include headache, dizziness, drowsiness, nausea, andvomiting. Diverse sensorimotor and intellectual impairments have alsobeen reported in response to carbon monoxide exposure. Thus, Putz etal.'5 exposed subjects to either 5, 35, or 70 ppm. of carbon monoxide fora period of four hours (producing mean carboxyhemoglobin levels of 1, 3,and 5%, respectively) and found a significant decrement in the perform-ance of tasks involving demanding eye-hand coordination and visual pe-ripheral monitoring of light intensities at the 70 ppm. level. Similarly,Horvath et al.16 reported that carbon monoxide levels of 111 ppm.,approximating the daily peak for a Los Angeles traffic jam and resultingin a carboxyhemoglobin of 6.6%, significantly impaired performance ona visual monitoring task under long monotonous testing trials, but notunder brief "alert" conditions. Evans3, in noting that other researchershave failed to find any direct effects of carbon monoxide inhalation onvigilance performance or brightness discrimination, suggests that thelevel of stimulation or demand of the task may be a critical factor. Hesuggests that isolated individuals, working continuously with few restbreaks under conditions of low stimulation, are most susceptible to sen-sorimotor decrements in response to low level carbon monoxide expo-sures. This description readily fits large numbers of employees currentlyengaged in such routine, repetitive office operations as stenographers,data entry operators, and video-display terminal users. Data presentedby Sterling and Kobayashi'0 indicate that carbon monoxide levels mayrange from 1 to 2 ppm. to as high as 64 ppm. in such environmentsdepending on ventilation conditions, presence or absence of tobaccosmoking, and outdoor pollution levels.

Finally, in discussing psychological responses to air pollution, it is im-portant to distinguish between the toxicologic characteristics of a pollu-tant and its aversive properties. The odor of an element, for example,may produce drastic alterations in mood state and demeanor, indepen-dently of any neuropathic effects associated with acute exposures. Rottenet al.17 exposed subjects to either a moderately offensive odor (ethyl mer-captan) or an extremely offensive smell (ammonium sulfide), and foundthat the moderately offensive odor, but not the extremely offensive one,increased aggressive tendencies relative to a nonexposed control group.


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The authors suggest that the failure of the highly obnoxious odor toheighten aggressive responses may have been due to a stronger drive toescape from the setting entirely. They also cite other research indicatingthat malodorous pollution depresses mood states, decreases liking forother people, and generally devalues the surroundings. Further, the cur-rent practice of dividing the world into smokers and nonsmokers seemsentirely justified in light of recent research indicating that nonsmokersfeel more anxious, irritated, and generally fatigued when subjected tocigarette smoke,18 and may, in fact, evidence increased feelings of aggres-sion.

It appears, therefore, that in addition to immediate neurological andphysiological responses to specific pollutants, complex psychologicalreactions involving mood state, motivation, and interpersonal relationsmay also be triggered. Odor, visibility, taste, and similar nontoxic yetaversive qualities of airborn pollutants are often a more immediate andobvious concern to an exposed individual than probabilistic statementsabout the potential long-range effects of chronic exposure. In this re-spect, pollution may be treated as a general stressor, exerting diffuse,nonspecific effects on the body. Selye's continuing study of the "pharma-cology of dirt" represents an attempt to understand this process in termsof the body's overall response to insult of any type. The individual, ofcourse, is not impervious to these changes and recognizes that somethingis wrong. Decrements in sensorimotor performance or intellectual func-tioning, mood changes and increased irritability, or feelings of mentaland physical fatigue and general malaise provide feedback to the individ-ual that his system is under stress. This is the psychological correlate ofSelye's general adaptative syndrome, and its study may be referred to asthe "psychology of dirt." Anxiety, tension, arousal, indeed, the term"stress" itself, have all been used to describe the vague psychologicalresponse that accompanies our awareness that the system is under chal-lenge. The way we interpret these altered physiological and psychologicalstates in terms of their presumed cause and significance will have impor-tant consequences for how we cope with fluctuations in these internalstates.

NONSPECIFIC EFFECTS OF AIR POLLUTION

We all have experienced anxiety, fright, or fear at some time. Givensuch situations, heart and breathing rates increase, and more blood flows


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PSYCHOLOGICAL~EFET

to the muscles than to the outer skin. Tremor, flushing, tenseness of mus-cles are other correlates of this experience. This is, of course, the patternof responses produced by a discharge of the sympathetic nervous systemin response to an acute stress, and we might predict that when one exper-iences such sensations, we correctly conclude that something is wrong. Ifwe can readily identify the cause for alarm, e.g., a reprimand from theboss, a backfiring car, an audit notice from the Internal Revenue Serv-ice, then we can place the threat in perspective and begin to marshalldefenses to deal with it. If, on the other hand, the stressor is not immedi-ately apparent or recognizable and we have no explanation or justifica-tion for our feelings, how can we interpret what is happening to us?

This is the situation created by Schacter and Singer,19 who injectedsubjects with adrenalin under the pretense that it was an experimentaldrug developed to increase visual acuity. Some of the subjects were in-formed about possible side-effects, and the signs of a sympathetic reac-tion were described. Other subjects were not informed about any poten-tial drug-induced effects so that when they experienced autonomic ner-vous system arousal they could have no ready explanation for their sub-jectively-experienced symptoms. Schacter and Singer predicted thatunder these conditions the distressed individual would look to the envi-ronment for an explanation of their aroused state and interpret theirautonomic response within this context. These predictions were con-firmed. When subjects were provided cues suggesting that they shouldfeel anger, they described their emotional state as angry; when providedwith cues suggesting euphoria, subjects described themselves as euphor-ic. Informed subjects and those who received a placebo and who did nottherefore experience an undifferentiated autonomic nervous systemresponse were not influenced by these social cues.

It appears then, that the individual is sensitive to fluctuations in thefunctioning of the autonomic nervous system. When perceived changesin his subjective state are understandable, e.g., "I have an allergy," "I'vebeen under a lot of pressure to meet a deadline," "I'm worried about myteenager," an individual can initiate various coping strategies to dealwith the causes. When the origins of the experienced distress are vagueor unclear, however, an individual starts searching around for salientcues. If the environment provides a plausible cause in the form of a pun-gent odor or dense, stuffy air, then an individual can conclude, rightly orwrongly, that the poor quality of the environment is responsible for hisphysical and psychological discomfort. Notice that this process can occur



M. J. COLLIGAN

independently of any specific toxic effects the environment might haveon the individual and irrespective of the "real" cause of the autonomicarousal. All that is required is that an individual experience autonomicarousal in response to a subtle or unidentified stressor or combination ofstressors. Cues provided by the environment in the form of noxiousodors, visually detectable particulates or dust, or humid, stuffy air, maysuggest to an individual that his discomfort is a toxic response to an air-born pollutant. That environment then becomes a source of threat to theindividual, which in turn may generate more autonomic arousal andanxiety.

This process may help us to understand the mass expression of symp-toms and complaints in certain closed environments where ambient levelsof known pollutants appear to be within acceptable ranges. One suchcase has been reported by Stahl and Lebedun.20 Approximately 35 keypunch operators at a university data processing center suddenly hadsymptoms of fainting, dizziness, and nausea after complaining of astrange odor in the work environment. Environmental testing of the pro-cessing center and medical examination of affected employees failed toidentify any specific cause of the illness. When several workers again be-came ill upon returning to work the second day, the center was againevacuated and additional testing of the work environment was per-formed. Although no known contaminants were found, the workers weretold that their illness was probably caused by a combination of transientatmospheric conditions which had now passed on. The workers thenreturned to work without further incident. Similar mass illness outbreakshave been described by others,21'22 and have alternately been labeled'mass hysteria," "mass conversion reaction," "hysterical contagion," or'mass psychogenic illness." Despite the lurid and controversial nature ofthese terms, the phenomenon itself is amenable to understanding usingthe model just described. If one assumes that the workers were understress for a period of time, either as a result of low-level chemical expo-sures, job-related pressures and work demands, the organization climate,or discomforting physical conditions, acting independently or in combi-nations, the workers may have experienced a general undifferentiatedstate of autonomic arousal with accompanying subjective, vague com-plaints. The detection of a salient cue in the environment in the form of anovel odor, stuffy and congested air, or a suspended haze may pose a dis-tinct threat and be rapidly perceived as the probable cause. The expres-


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sion of these complaints aid subsequent fear regarding the quality of theenvironment then spreads rapidly throughout the work setting. The resultis a mass reaction to a shared perceived threat.That this may have been the case in the mystery gas episode described

by Stahl and Lebedun is suggested because workers complained ofnumerous stresses associated with their work. In addition to the boringand repetitive nature of the job itself, they complained of an authoritar-ian and dictatorial management style, unrealistic standards, noise, andpoor supervisory relations. Under these conditions the appearance of astrange smell may have triggered an episode of illness.

In conclusion, then, the quality of indoor air may psychologically af-fect an individual in two ways. The first involves direct and specificneurobehavioral effects of the individual pollutants. This is the tradi-tional domain of behavioral toxicology, where the focus is on the impactof chemical elements on such response systems as information process-ing, sensorimotor performance, and learning.The second way in which pollution may affect psychological function-

ing is more diffuse, and involves the overall impact of the environment onthe autonomic system. In this respect, air quality is one of many possiblesources of stress that challenge the organism, producing a state ofgeneral discomfort. The process by which an individual comes to inter-pret his internal states, to understand their significance in terms of hishealth and well being, and finally to identify a probable cause are impor-tant complex steps in deciding how to cope with the situation. The man-ner in which low-level chemical exposures may interact with otherphysical, social, and psychological stressors to threaten individual healthis not presently known. The impact of nontoxic but aversive properties ofvarious chemicals on an individual's level of general arousal, perceivedthreat, and anxiety have yet to be defined. These are real and importantconsiderations for an individual who has to interpret the meaning of anodor, haze, or particulate concentration in terms of his immediate andlong-range health.

SUMMARY

This paper suggests that indoor air pollution may affect psychologicalfunctioning -in two ways. The first involves the specific, direct effect ofparticular pollutants on select behavioral systems, e.g., memory and sen-



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sorimotor performance, as traditionally studied by behavioral tox-icologists. The second involves the general arousal of the autonomic ner-vous system, resulting in increases in perceived tension and anxiety. Theindividual's interpretation of and reaction to these experiencedphysiological and psychological reactions are discussed in terms of'symptom" recognition and attribution.

Questions and Answers

DR. PETER PREUSS (Consumer Product Safety Commission): In youropinion, what is the possibility that this phenomenon of mass hysteriacould occur in isolated individuals or separated individuals as a result ofa common suggestion, perhaps?DR. COLLIGAN: A similar case has been described in the literature. It

has been some time since I read the article, but, as I recall, a strangeodor was pumped into the environment from a plant in Mattoon, Ill.Someone became ill and attributed his illness to this odor. It waspublished in the newspaper and described as a mystery gas or somethingto that effect. Within a short period of time, other people experiencingsimilar illnesses began to attribute them to this cause. That is not to saythat it may not have been the cause, but to indicate that the press cancertainly suggest probable causes for perceived variations in internalstates. Although there was no face-to-face interaction or contact in thatcase, there was still a communication network operating through themedia and the press.At a more concrete level, I think, we might ask about the dispersion of

flus and viruses and bugs and things of this nature throughout an officecomplex as a result of communication networks. Frequently, when wefeel poorly and someone suggests that a bug is going around, this is allthe justification we need to remove us from the work environment for acouple of days. Staying home then becomes a legitimate response to thatillness. It is not just that we are feeling badly; we now have a bug that isresponsible for the way we feel, and the way to treat that is to stay homeand get some rest. The whole process of recognizing changes in our inter-nal states, labeling them (e.g., am I sick or is it simply a transient phe-nomenon that will pass?) and, once labeled, deciding how to respond tothose changes is an important consideration in something like indoor airpollution or for anyone involved in the domain of public health.


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DR. MERRIL EISENBUD (New York University Institute of Environ-mental Medicine): I think one of the most confusing factors can be theamateur epidemiologist who asks his workmates when they sleep nightsand whether they have had sexual problems. Many of us in this roomhave been confronted by a bill of particulars in which, I must say, theprivate physician frequently has helped. People will go to a private physi-cian and say, "There is a terrible odor where I work and I cannot sleepnights," and the physician will say, "Maybe you had better get yourmanagement to do something about it," although there is really no wayin which one can explain sleeplessness with, let us say, a small dose offormaldehyde.

DR. COLLIGAN: From the point of view of the individual, a foul-smell-ing odor may be perceived as more toxic than a pleasant-smelling odor ora chemical that has no odorous qualities.DR. MORTON TEICH (Mount Sinai Medical Center): I am an allergist

and clinical ecologist in New York City. We work on the basis of additivefactors with a threshold, and we feel that psychological aspects are part ofit. In other words, one may add that little noxious gas to dust sensitivityand everything else and, starting with a slight problem, they will go beyondthe threshold. One small additive factor may make the difference.

DR. COLLIGAN: I think that is one of the reasons for looking, generally,at pollutants as just one source of environmental stress, in addition toheat and cold variations and interpersonal stresses that might be pres-ent in a particular environment. These things can interact and produce asynergistic response.DR. TEICH: In the office we provoke symptoms with such things as

chemicals and foods and so on, and we find that we can create the samepsychological problems in the office and actually neutralize them withspecific doses.DR. JAMES L. BEALL (U.S. Department of Energy): To add to your

comment on communication among employees, I really think that itought to be encouraged and not looked upon as some sort of masshysteria without basis. I say that because we have the example ofdibromochloropropane workers in California getting together over coffeeand discussing their relative inabilities to produce offspring, which led tothe entire set of events that followed, including some regulations ondibromochloropropane.DR. DEAN BAKER (National Institute of Occupational Safety and

Health): I was interested in your remarks about the experiments in which



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the subjects knew what their response might be and that actually changedthe outcome. One of the things that we have found in investigations ofbuildings is that lack of knowledge about the dynamics of what was goingon seemed to perpetuate the situation. I wonder if you have done twothings: looked at the organizational factors that may be more likely toprecipitate these reactions and examined the kind of management inter-ventions that can be taken to deal with this situation when it arises.

DR. COLLIGAN: The cases that I have specifically been involved in werein industrial settings, which are messier to deal with in terms of indus-trial hygiene factors and of epidemiology. The organizational structuresin which the cases that we investigated occurred may be characterized asrather rigid and authoritarian and unilateral, going from the top down.Frequently, the employees would complain about various conditions inthe work environment, and the management response would besomewhat patronizing, so that the autonomic arousal would continuealong with fluctuations in mood states, anxiety, and transient physicaldiscomfort. All the workers need, then, is a probable cause which willhelp them understand their particular discomfort.The National Institute of Occupational Safety and Health has no en-

forcement capabilities. We suggest various ways that management mightaddress certain concerns. For example, formation of a workers' safetyand health committee establishes a channel of communication in termsof problems that are perceived in the workplace. We frequently suggestthat they hire a labor management consultant to help to identify otherproblems to get their house in order. The structure of the organization isan extremely important factor in situations like this. Coupled with that isthe workers' concern that others are not perceiving their illness to be le-gitimate, with the implication that they are malingering or faking or thatwhat they are feeling is not somehow real, and it certainly is.

DR. JAMES REPACE (U.S. Environmental Protection Agency): Thishas been my perception of the problem. Many complaints are called in tothe Environmental Protection Agency that seem to have a commonthread. Management tends to blame the victim for the problem, con-tending that it is a problem personal to the victim and has nothing to dowith the building itself. The victims may begin to talk to one another andthe building gets a bad reputation. Then people begin to take an increasedamount of sick leave and try to avoid going into the building. Productivi-ty drops and the problem snowballs. Of course, it is true that there could


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be problems of mass hysteria, but there usually is a foundation for it.If people feel well when they are home and they go to work and get

sick, with no identifiable stress on them, if they go home again and feelbetter, and if they go back to work and feel disoriented and confused orhave skin rashes they know pretty well that there is a problem with thebuilding. If management does nothing, then the whole labor-manage-ment relationship can deteriorate.DR. EISENBUD: We are talking about a very toxic response if people go

to work and become disoriented and develop skin rashes.DR. REPACE: Sure. There are a lot of those problems, or at least my

perception is that there are a lot of them. I get a lot of calls.DR. EISENBUD: Then there ought to be something there causing it.DR. COLLIGAN: There are also people who go to work and develop a

headache and muscular tension in the back of their neck and a generalnauseous feeling in the pit of their stomach which might be unrelated toany chemical exposure, but they also notice that when they are at workthey feel bad and at home they feel better. Then all they need is for astrange odor to be present in the workplace or for a new solvent to be in-troduced or a new photocopying machine to be set into place, and theyhave localized their problems.DR. HARVEY SACHS (Princeton University): There have recently been

descriptions in Science, at least, of the converse reaction of painters, inparticular, not feeling well except when they were at work and exposed tofumes. How common is this converse? Is it a form of addiction ordependency reaction?

DR. COLLIGAN: I really cannot address that. I have not seen the arti-cle, nor do I know anything about it.

DR. TEICH: We have seen such addiction and withdrawal symptoms.When they go back to the paint, they do very well: if they are awayfrom the paint for a few days they get severe withdrawal reactions.

REFERENCES

1. Dubos, R.: The human environment.Sci. J. 5:75-80, 1969.

2. Selye, H.: The Stress of Life. NewYork, McGraw-Hill, 1956.

3. Evans, G. W. and Jacobs, S. V.: Airpollution and human behavior. J.Soc. Issues 37.95-125, 1981.

4. Izmerov, N. F.: Establishment of air

quality standards: Definition of thefirst effects of air pollution. Arch. En-viron Health 22:711-19, 1971.

5. Strahilevitz, M., Strahilevitz, A., andMiller, J.: Air pollutants and the ad-mission rate of psychiatric patients.Am. J. Psychiatry 136:205-07, 1979.

6. Key, M. M., Henschel, A.F., Butler,


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J., et al., editors: Occupational Dis-eases: A Guide to Their Recognition.DHEW (NIOSH) Publication No.77-181. Washington, D.C., Govt.Print. Off., 1977.

7. Lefcoe, N. M. and Inculet, I. I. Par-ticulates in domestic premises. Arch.Environ. Health 30:565-70, 1975.

8. Lagerwerff, J. M.: Prolonged ozoneinhalation and its effect on visualparameters. Aerosp. Med. 34:479-86,1963.

9. Hore, T. and Gibson, D. E.: Ozoneexposure and intelligence tests. Arch.Environ. Health 17:77-79, 1968.

10. Sterling, T. D. and Kobayashi, D. M.:Exposure to pollutants in enclosed"living spaces." Environ. Res.13:1-35, 1977.

11. Breisacher, P.: Neuropsychologicaleffects of air pollution. Am. Behav.Sci. 14:837-64, 1971.

12. Hoegg, U. R.: Cigarette smoke in closedplaces. Environ. Health Perspect.2:117-28, 1972.

13. Repace, J. L. and Lowrey, A. H.: In-door air pollution, tobacco smoke,and public health. Science 208:464-72, 1980.

14. Yocum, J. E., Clink, W. L., andCote, W. A.: Indoor/outdoor air qual-ity relationships. J. A.P. C.A. 21:251-59, 1971.

15. Putz, V., Johnson, B. L., and Setzer,

J. V. Effects of CO on Vigilance Per-formance. DHEW (NIOSH) Publica-tion No. 77-124. Washington, D.C.Govt. Print. Off., 1977.

16. Horvath, S. V. and Dahms, T. E.Carbon monoxide and human vigi-lance: A deleterious effect of presenturban concentrations. Arch. Environ.Health 23:343-47, 1971.

17. Rotton, J., Frey, J., Barry, T., et al.:The air pollution experience andphysical aggression. J. Appl. Soc.Psychol. 9:397-412, 1979.

18. Jones, J. W.: Adverse emotional reac-tions of nonsmokers to secondarycigarette smoke. Environ. Psychol.Nonverbal Behav. 3:125-27, 1978.

19. Schachters, S. and Singer, J.:Cognitive, social, and physiologicaldeterminants of emotional state.Psychol. Rev. 69:379-99, 1962.

20. Stahl, S. M. and Lebedun, M.:Mystery gas: An analysis of masshysteria. J. Health Soc. Behav.15:44-50, 1974.

21. Kerckhoff, A. C. and Back, K. W.:The June Bug: A Study of HystericalContagion. New York, Appleton-Cen-tury-Crofts, 1968.

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the psychological effects indoor airpollution*...m. j. colligan domestic and nonindustrial...

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