Ventilation and health in non-industrial indoor environments: report from a European Multidisciplinary Scientific Consensus Meeting (EUROVEN)

Ventilation and health in non-industrial indoor environments:

report from a European Multidisciplinary Scientific Consensus

Meeting (EUROVEN)

Introduction

Ventilation is the process of exchanging indoor (pol-luted) air with outdoor (presumably fresh and clean)air. Its main purpose is to create optimal conditions for

humans in indoor environments, taking into accounttheir health, comfort, and productivity by providing airfor breathing, for removing and diluting indoorpollutants, for adding or removing moisture, and forheating or cooling.

Abstract Scientific literature on the effects of ventilation on health, comfort, andproductivity in non-industrial indoor environments (offices, schools, homes, etc.)has been reviewed by a multidisciplinary group of European scientists, calledEUROVEN, with expertise in medicine, epidemiology, toxicology, and engin-eering. The group reviewed 105 papers published in peer-reviewed scientificjournals and judged 30 as conclusive, providing sufficient information on ven-tilation, health effects, data processing, and reporting, 14 as providing relevantbackground information on the issue, 43 as relevant but non-informative orinconclusive, and 18 as irrelevant for the issue discussed. Based on the data inpapers judged conclusive, the group agreed that ventilation is strongly associatedwith comfort (perceived air quality) and health [Sick Building Syndrome (SBS)symptoms, inflammation, infections, asthma, allergy, short-term sick leave], andthat an association between ventilation and productivity (performance of officework) is indicated. The group also concluded that increasing outdoor air supplyrates in non-industrial environments improves perceived air quality; that out-door air supply rates below 25 l/s per person increase the risk of SBS symptoms,increase short-term sick leave, and decrease productivity among occupants ofoffice buildings; and that ventilation rates above 0.5 air changes per hour (h)1) inhomes reduce infestation of house dust mites in Nordic countries. The groupconcluded additionally that the literature indicates that in buildings with air-conditioning systems there may be an increased risk of SBS symptoms comparedwith naturally or mechanically ventilated buildings, and that improper main-tenance, design, and functioning of air-conditioning systems contributes toincreased prevalence of SBS symptoms.

P. Wargocki1*, J. Sundell1**,W. Bischof2, G. Brundrett3,P. O. Fanger1, F. Gyntelberg4,S. O. Hanssen5, P. Harrison6,A. Pickering7, O. Sepp)nen8,P. Wouters91Technical University of Denmark, Kongens Lyngby,Denmark, 2Friedrich-Schiller-Universit�t Jena, Erfurt,Germany, 3 Royal Society of Health, London, UnitedKingdom, 4Bispebjerg Hospital, Copenhagen, Denmark,5Norwegian University of Science and Technology,Trondheim, Norway, 6MRC Institute for Environmentand Health, Leicester, United Kingdom, 7WythenshaweHospital, Manchester, United Kingdom, 8HelsinkiUniversity of Technology, Espoo, Finland, 9BelgianBuilding Research Institute, Brussels, Belgium

Key words: Ventilation; Outdoor air supply rate;Ventilation system; Non-industrial indoor environments;Offices; Schools; Homes; Health; EUROVEN.

P. WargockiInternational Center for Indoor Environment and Energy,Technical University of Denmark, Building 402DK-2800 Kongens Lyngby, DenmarkTel.: +45 45 25 40 11Fax: +45 45 93 21 66e-mail: [email protected]*Scientific Secretary.**Chairman and project leader.

Received for review 27 June 2001. Accepted forpublication 20 July 2001.� Indoor Air (2002)

Practical ImplicationsVentilation requirements in many existing guidelines and standards may be too low to protect occupants of offices,schools, and homes from health and comfort problems and may not be optimal for human productivity. Higherventilation rates can increase energy costs in relation to building operation, but these can be reduced by loweringpollution loads on the air indoors, e.g., by prudent and systematic maintenance of heating/ventilation/air-conditioning(HVAC) systems and by reducing superfluous pollution sources indoors. Energy costs can also be reduced by usingefficient heat recovery systems. Source control and new ways of conditioning air are required.

Indoor Air 2002; 12: 113–128http://www.blackwellmunksgaard.comPrinted in Denmark. All rights reserved

Copyright � Blackwell Munksgaard 2002

INDOOR AIRISSN 0905-6947

113

Several literature reviews have been published on theeffects of ventilation on health. Their main andcommon conclusion was that the ventilation rates ator below 10 l/s per person can significantly aggravatehealth outcomes, mainly Sick Building Syndrome(SBS) symptoms (Godish and Spengler, 1996; Mendell,1993; Menzies and Bourbeau, 1997; Seppanen et al.,1999) and that there is an indication that increasing theventilation rate from 10 l/s per person up to 20 l/s perperson may further reduce SBS symptoms (Seppanenet al., 1999). The reviews have shown, additionally,that an increased prevalence of SBS symptoms isassociated with the use of air-conditioning in buildings(Mendell and Smith, 1990; Menzies and Bourbeau,1997). These literature reviews included studies pub-lished in peer-reviewed journals and in conferenceproceedings without scrutinizing their scientific merit ina multidisciplinary fashion as in, e.g. Nordic interdis-ciplinary reviews (Sundell and Bornehag, 1999). Con-sequently, the European Multidisciplinary ScientificNetwork on Indoor Environment and Health con-cerning associations between ventilation and health(EUROVEN) was established in order to create amultidisciplinary forum for adequate communicationof scientific results between different disciplines. Thepurpose of EUROVEN is to define the link betweenventilation and health in non-industrial indoor envi-ronments. To reach this goal, scientists with anexpertise in medicine, epidemiology, toxicology, andengineering reviewed the peer-reviewed scientific stud-ies coming with the scope of EUROVEN. The presentpaper describes their work and the final consensusstatement reached by the EUROVEN group.

Methods

The scientific peer-reviewed literature on the effects ofventilation on health in non-industrial indoor environ-ments was reviewed by a multidisciplinary group ofEuropean scientists with expertise in medicine, epi-demiology, toxicology, and engineering. In the presentwork, the term �ventilation� describes both the ventila-tion rate, i.e. the amount of outdoor air supplied toindoor spaces unless otherwise indicated, and theventilation system, i.e. the way the air is supplied toindoor spaces – naturally or mechanically, with orwithout air-conditioning. Natural ventilation is definedas an airflow caused by pressure from wind and/orindoor–outdoor temperature differences. Mechanicalventilation is defined as an airflow caused by a fanthrough intake and/or exhaust vents specificallyinstalled for ventilation (ASHRAE, 1993). Mechanicalventilation without air-conditioning is defined as amechanical ventilation system in which the supply air isfiltered and heated, or in which the air is exhausted bya fan. Mechanical ventilation with air-conditioning isdefined as a mechanical ventilation system in which the

supply air is filtered and heated, and is additionallycooled and/or humidified and/or dehumidified. Healthis understood very broadly reflecting the basic defini-tion of the World Health Organization (WHO, 1948),which states that health is a state of complete physical,mental, and social well-being and not merely theabsence of disease or infirmity. Consequently, studieson the effects of ventilation on human comfort andproductivity were also taken into account. Non-indus-trial indoor environments are represented by all kindsof indoor environments not related to industrialexposures.The scientific literature was gathered by searching

through the following databases: MEDLINE byNational Library of Medicine; Cambridge ScientificAbstracts (including Mechanical EngineeringAbstracts, Environmental Sciences, and PollutionManagement Search subfiles, Biological SciencesSearch subfiles, TOXLINE, ERIC, Computer andInformation System Abstracts) and AIRBASE by theAir Infiltration and Ventilation Center (AIVC). Theselected databases cover papers published in scientificjournals from 1966 (two earlier papers from 1936 and1955 were also included in the review). Four categoriesof search profiles were established: ventilation, envi-ronment, health, and publication, each with severalsearching records. As a source of search records,keyword indexes of the international conferencesIndoor Air 1990, 1993 and 1999, and Healthy Build-ings 1997 and 2000, were used. Only papers with title,keywords or abstract including records in each of thefour search categories were selected. The category�ventilation� included 25 different records pertaining toventilation rates, e.g. air change rate, air supply rate,etc., as well as ventilation systems, e.g. natural venti-lation, mechanical ventilation, etc. The category �envi-ronment� included 49 different records pertaining tonon-industrial indoor environments, e.g. dwellings,schools, offices, etc. The category �health� included 91different records pertaining to health, comfort, andproductivity, e.g. symptoms, diseases, odor, perceivedair quality, absenteeism, productivity, asthma, etc. Thecategory �publication� included three records pertainingto peer-reviewed publications: journal article, journalpaper, ASHRAE Transactions.More than 200 papers were gathered by searching

databases. They were then screened through theirabstracts to exclude articles that did not pertain to theEUROVEN scope, reviews, as well as the papersconcerning Legionnaires disease, humidifier fever, andradon. After this initial screening, 105 papers wereselected and thoroughly reviewed by nine scientists.Each paper was reviewed by two scientists, oneassigned to be a prime reviewer and the other oneassigned to be secondary reviewer. Each scientistreviewed 23 or 24 papers, half of them as primereviewer. The articles were assigned to scientists for

Wargocki et al.

114

review completely at random; however, no paper wasassigned to a scientist if he was one of the authors.When reviewing the paper, information on differentaspects of the study was collected including design,methods, data analysis, measurements of airflow ratesand effects on health, possible bias, etc., its results andmain conclusions. Reviewed papers were then classifiedas: relevant and conclusive – providing sufficientinformation on ventilation, health effects, data pro-cessing, and reporting; relevant but non-informative –lacking essential information concerning ventilation orhealth effects; relevant but inconclusive – with incom-plete data processing or reporting; background articles– providing additional background information deal-ing with the EUROVEN scope; irrelevant – not dealingwith the EUROVEN scope or describing case studies.Classification of each paper was first made independ-ently by each reviewer. Then, during the plenarymeeting, the whole group decided on a final classifica-tion. The data in the papers judged during plenarydiscussions of the whole EUROVEN group as conclu-sive were used to formulate the final consensusstatement and conclusions.

Results

Of the 105 papers reviewed by the group (see thesubsection in the References for the complete list), 61papers were excluded: 18 were judged to provideinformation that was irrelevant to the scope of thepresent work or were classified as case studies(marked by an asterix, *, in the reference list), and43 were judged to be either non-informative orinconclusive. Of the remaining 44 papers, 14 werejudged to provide background information relevantto the EUROVEN scope and 30 were judgedconclusive and thus used to formulate the consensusstatement. Thirty papers judged as conclusive werepublished in 17 different peer-reviewed scientificjournals (Table 1) with specialties ranging fromengineering to medical sciences, epidemiology, occu-pational hygiene, and allergy, and described ninestudies carried out in the USA and 21 in Europe, ofwhich 17 were conducted in European Nordic coun-tries (Denmark, Finland, Norway, Sweden). Thestudies were carried out in more than 1000 buildingscomprising offices, assembly halls, schools, homes,jails, and nursery homes with more than 65,000occupants comprising children, adults, and seniorcitizens. Most studies were carried out during thewinter, spring or autumn season.Table 2 lists the papers judged by the group to be

non-informative or inconclusive and provides thereason for such classification, which was mainly thelack of proper statistical analysis and control ofconfounding factors. Many of the papers listed inTable 2 assumed that outdoor air was clean, that

heating/ventilation/air-conditioning (HVAC) systemswere cleaned, and that pollution loads in differentbuildings were similar; many of them did not mentionwhether the air was recirculated or whether themeasured airflow rate was the total or the outdoorair supply rate.Table 3 shows data from 14 papers providing back-

ground information for the EUROVEN work. Theydescribe experimental studies on ventilation require-ments to control perceived air quality in spacespolluted by bioeffluents emitted by humans, in spacespolluted by tobacco smoke, and in spaces polluted byemissions from building materials, and experimentsshowing that HVAC system components can aggravatethe perceived air quality in spaces. They also presentstudies investigating the association between mortalityin hot weather and the presence of air-conditioning,thus indicating a positive thermal impact of air-conditioning on human health, as well as studiesindicating that increasing the ventilation rate candecrease the risk of infections.The data from 22 papers judged by the group to be

conclusive, presented in Table 4, show that increasingthe ventilation rate improves perceived air quality,decreases the prevalence of SBS symptoms and theintensity of clinical symptoms, reduces absenteeism, andimproves the performance of office work; only in twostudies was no effect of a changed ventilation rateobserved (Jaakkola et al., 1991a,b; Menzies et al.,1993). The outdoor air supply rates in the studiespresented in Table 4 ranged from 0 to 50 l/s per person.The data from nine papers judged by the group to

be conclusive, presented in Table 5, suggest that therisk of SBS symptoms is higher in air-conditionedbuildings compared with naturally or mechanicallyventilated buildings (six of seven papers), that therisk of infections increases with the presence ofrecirculation (one paper), and that dirty HVAC

Table 1 List of scientific journals in which the papers judged relevant were published

Journal name No. of papers

Allergy 2American Journal of Epidemiology 1Annals of Occupational Hygiene 1Applied Occupational and Environmental Hygiene 1Archives of Environmental Health 1Energy and Buildings 2Environment International 2Epidemiology 2Indoor Air 8International Archives of Occupational and Environmental Health 1International Journal of Epidemiology 1JAMA ) Journal of the American Medical Association 1Journal of Allergy and Clinical Immunology 1Journal of the American Geriatrics Society 1New England Journal of Medicine 2Occupational and Environmental Medicine 2Scandinavian Journal of Work, Environment & Health 1

Ventilation and health in non-industrial indoor environments

115

systems can increase the risk of SBS symptoms (onepaper).

Discussion

Ventilation is a method for removing or dilutingpollutants that are potentially harmful to humans.The presence of associations between ventilation andhealth, comfort and productivity shown by thestudies judged conclusive (Table 4) indicates thatventilation is an effective means of protecting peopleindoors from pollutants. The presence of such anassociation, however, does not indicate which kind ofpollutants are of concern. Outdoor air supply ratesrequired for indoor environments depend on the loadof pollutants indoors; a good example of an inter-action between ventilation and pollution load isshown by Øie et al. (1999). Hypothetically, in indoorspaces without any pollutants, the required ventila-tion rate would equal the outdoor air supply ratenecessary for human metabolism, i.e. depending onactivity from 0.1 to 0.9 l/s per person. In real life,indoor environments are not free of pollution andthey also differ as regards pollution loads. It isconsequently difficult to set the ventilation rate thatwould meet ventilation requirements for health in allkinds of indoor environment. The scientific data can,however, be used to examine whether health andcomfort problems are more likely if the outdoor airsupply rate is below a certain level. Such an approachwas adopted by the EUROVEN group and based onthe results in the studies judged conclusive (Table 4), itwas concluded that outdoor air supply rates below25 l/s per person in offices can increase the risk ofhealth and comfort problems and can reduce produc-tivity, and that a similar relation is likely for schools.Furthermore, the studies judged conclusive showedthat air change rates below 0.5 h)1 in homes in Nordiccountries can increase the rate of infestation of housedust mites. As a causal relationship exists betweenhouse dust mite infestation and allergy (Andersen andKorsgaard, 1986), these data imply that low ventila-tion rates in homes may be one of the factorsexacerbating allergies.

Table 2 List of papers reviewed by the group but judged inconclusive or non-informative

Paper Reason for exclusion

Abbritti et al. (1992) Incomplete control of confoundingfactors (different buildings compared)

Incomplete control of confoundingfactors (different buildings compared)

Bachmann et al. (1995)

Beck et al. (1989) Incomplete analysisBourbeau et al. (1996) Incomplete control

of confounding factorsBourbeau et al. (1997) Incomplete control of

confounding factorsFinnegan et al. (1984) Incomplete control of confounding

factors (different buildings compared)Incomplete control of confoundingfactors (different buildings compared)

Gibert et al. (1992)

Haghighat and Donnini (1999) Incomplete analysisHarving et al. (1994) No data on ventilation ratesHedge et al. (1989) No measurements of airflowHedge et al. (1995) Insufficient dataHedge et al. (1996) Insufficient dataHill et al. (1992) Incomplete analysis (lack of

adjustments); relatively small sampleHosein et al. (1989) Incomplete analysis (no analysis in

terms of ventilation); no airflowmeasurements

Iversen et al. (1986) Incomplete analysisJaakkola et al. (1994) Too short exposure period (1 week) to observe

effects of interventionKodama and McGee (1986) Insufficient dataKroeling (1988) No control of confounding factors

(lack of adjustments); noinformation on ventilation

Menzies et al. (1997) Potential bias in the results (lack of blinding)Muzi et al. (1998) Incomplete control of confounding

factors (differentbuildings compared)

Nelson et al. (1995) Incomplete analysisNorb�ck (1995) Incomplete analysis; no information

on ventilation ratesNorb�ck and Edling (1991) Exposure data based on people's

report rather than onmeasurements

Norb�ck et al. (1990a) Dubious design of the study(all selected buildings were sick)

Norb�ck et al. (1990b) Incomplete control of confounding factorsNordstrGm et al. (1995a) Incomplete analysisNordstrGm et al. (1995b) Incomplete analysisPejtersen et al. (2001) Confounded interventions (impossible

to separate the effect of ventilation);unmatched case-control study

Robertson (1989) Incomplete control of confoundingfactors (different buildings compared)

Robertson et al. (1985) Incomplete control of confoundingfactors (different buildings compared)

Rowe et al. (1993) Incomplete analysis; retrospective studyRuotsalainen et al. (1991) No control of confounding factors

(crude analyses); incompletemeasurements

Ruotsalainen et al. (1994) Incomplete control of confounding factors(no control of windows opening)

Skov and Valbjørn (1987) No control of confounding factors (crudeanalysis)

Smedje et al. (1997) Incomplete information on analysis of resultsStenberg et al. (1995) Insufficient data on ventilation ratesSterling and Sterling (1983) Incomplete control of confounding factors

(different buildings compared)

Table 2 (Continued)

Paper Reason for exclusion

Teculescu et al. (1998) Incomplete control of confoundingfactors (different buildings compared)

Vincent et al. (1997) Too low response rateWieslander et al. (1999) Health-biased study; incomplete

control of confounding factorsWyon (1992) Insufficient dataWIlinder et al. (1997a) Incomplete control of confounding

factors (different buildings compared)WIlinder et al. (1997b) Incomplete control of confounding

factors (different buildings compared)

Wargocki et al.

116

Table3Su

mmaryof

papers

judged

toprovidebackground

inform

ationrelevant

toEU

ROVE

Nscope

Paper

Results

Design

Buildings

Populatio

nVe

ntilatio

ntype

Outdoorair

supply

rates

CO2

concentra

tion

Windows

Effect

measurement

Data

analysis

Comments

Berg-M

unch

etal.(1986)

Ventilatio

nrequire

ments

for

acceptable

indoor

airquality

inthe

presence

ofhuman

bioeffluents

Experim

ent

Auditoriu

m(n

¼1)

Adults

(n¼

106

wom

en)

Mechanical

Range:

5–20

l/(sp)

calculated

usingCO

2

concentra

tion

assumingCO

2

productio

nof

16l/(hp)

Range:

600–

1500

ppm

Nodata

Panelo

f79

untra

ined

judges

and

occupants

(n¼

106)

assess-

ingacceptability

ofairquality

andodor

intensity

Linear

regression

8l/(sp)

corre

sponds

to20%

visitors

dissatisfie

dwith

theairquality

Bjorkroth

etal.(1998)

Thecomponents

ofHV

ACsystem

canbe

asource

ofpollutio

n

Experim

ent

Cham

ber

exposures

NA

Air- conditioning

with

diffe

rent

components

installed

Range:

100–

600l/s

NA

NA

Pane

lof12

trained

judges

assessing

perceivedair

quality

Increasing

airflow

didnot

improveairquality

down-

stream

ofthecomponent;

odor

emissionsincreased

with

airvelocity

Cain

etal.

(1983)

Ventilatio

nrequire

ments

for

acceptable

indoor

airquality

inthe

presence

ofhuman

bioeffluents

Experim

ent

Cham

ber

exposures

Adults

(n¼

4,8or

12people

occupying

cham

ber)

Air- conditioning

2.5,

5,7.5

and10

l/(sp)

Nodata

NA

165subjects

assessing

odor

intensity

and

acceptability

asvisitors

and

occupants

Linear

regression

7.5l/(sp)

require

dto

assure

that

80%

ofvisitors

toaspacejudgetheair

quality

tobe

acceptable

Cain

etal.

(1983)

Ventilatio

nrequire

ments

for

acceptable

indoor

air

quality

inthe

presence

oftobacco

smoking

Experim

ent

Cham

ber

exposures

Adults

(n¼

4people

occupying

cham

ber)

Air- conditioning

5.5,

8,10,

17.5

and34

l/(sp)

(smoking

rates:

4,8

and16

cigarette

s/h)

Nodata

NA

92subjects

assessing

odor

intensity

and

acceptability

asvisitors

andoccupants

Linear

regression

78–1

20m3percigarette

require

dto

ensure

that

75–8

0%of

visitors

toaspacejudgethe

airquality

tobe

acceptable;3

0brands

ofcigarette

ssm

oked

but

thecompositio

nof

tobacco

smokecouldchange

sincethe

experim

ents

werecarried

out

before

1982

Everettand

Kipp

(1991)

Increasing

the

ventilatio

nrate

insummer

months

decreasedinfection

rates

Experim

ent

Hospita

loperating

room

(n¼

3)

Adults

(n¼

1998

patie

nts)

Air- conditioning

Range:

6.3–

16.6

h)1

Closed

Nodata

Wound

infectionrate

v2-te

stIncreasedventilatio

ncanprotectagainstinfections

Fanger

(1988)

Ventilatio

nrequire

ments

for

acceptable

indoor

air

quality

inthe

presence

ofhuman

bioeffluents

Experim

ent

Auditoriu

m(n

¼2)

Adults

(n>1000)

Mechanical

Range:

5–35

l/(sp)

Range:

400–

1500

ppm

Nodata

Panelo

f168

untra

ined

judges

assessing

acceptability

ofairquality

Linear

regression

Paperintro

ducestw

onew

units,

olfanddecipol,to

quantifyair

pollutio

nsourcesindoorsand

airquality

asitis

perceived

byhumansindoors


117

Table3(Contin

ued)

Paper

Results

Design

Buildings

Populatio

nVe

ntilatio

ntype

Outdoorair

supply

rates

CO2

concentra

tion

Windows

Effect

measurement

Data

analysis

Comments

Gunnarsen

(1997)

Ventilatio

nrequ

iremen

tsfor

acceptab

leindo

orairqu

ality

inthe

presen

ceof

emis-

sion

sfro

mbu

ildingmaterials

Expe

rimen

tCh

ambe

rexpo

sures

NA

Mecha

nical

Rang

e:0.5–

5h)

1

(<0.1–

10l/(sm

2floor)

NA

NA

Pane

lof15

trained

subjects

assessing

perceivedair

quality

Line

arregression

Four

sing

lebu

ildingmaterials

were

tested

;sen

sory

source

streng

th(emission

rate)increased

for

somebu

ildingmaterials

with

the

ventilatio

nrate,w

hich

coun

ter-

acts

thepo

sitiveeffect

ofventi-

latio

non

perceivedairqu

ality

Iwashita

etal.

(199

0)Ve

ntilatio

nrequ

ire-

men

tsforaccep-

tableindo

orair

quality

inthepre-

senceof

human

bioe

fflue

nts

Expe

rimen

tCh

ambe

rexpo

sures

Adults

(n¼

54)

Air-c

onditio

ning

Rang

e:0.7–

10l/(sp)

Rang

e:80

0–80

00pp

mNA

Pane

lof10

7un

trained

judg

esassessingaccep-

tabilityof

airqu

ality

andod

orintensity

Line

arregression

;prob

itan

alysis

7l/(sp)

corre

spon

dsto

20%

visitors

dissatisfie

dwith

the

airqu

ality

Knud

senet

al.

(199

7)Ve

ntilatio

nrequ

iremen

tsfor

acceptab

leindo

orairqu

ality

inthe

presen

ceof

emission

sfro

mbu

ildingmaterials

Expe

rimen

tCh

ambe

rexpo

sures

NA

Mecha

nical

Rang

e:0.2–

20l/s

perm2of

material

sample

NA

NA

Pane

lof10

–14

trained

subjects

assessing

perceived

airqu

ality

Line

arregression

;prob

itan

alysis

Eigh

tsing

lebu

ildingmaterials

and

onemixture

ofmaterials

tested

;expo

sure–respo

nserelatio

nships

betw

eentheconcen

tratio

nof

airpo

llutantsan

dpe

rceivedair

quality

diffe

redbe

twee

nmaterials;the

sensoryem

ission

rate

foramaterialm

aychan

gewith

thepo

llutio

nconcen

tratio

nin

theair

Knud

senet

al.

(199

8)Ve

ntilatio

nrequ

iremen

tsfor

acceptab

leindo

orairqu

ality

inthe

presen

ceof

emission

sfro

mbu

ilding

materials

Expe

rimen

tCh

ambe

rexpo

sures

NA

Mecha

nical

Rang

e:0.6–

10l/s

perm2of

material

sample

NA

NA

Pane

lof33

–41

untra

ined

subjects

assessing

acceptab

ility

ofairqu

ality

Line

arregression

Eigh

tsing

lebu

ildingmaterials

tested

;the

perceivedpo

llutio

nfro

mmaterials

decrea

sedwith

increa

sedventilatio

n;expo

sure–respo

nserelatio

nships

betw

eentheconcen

tratio

nof

airpo

llutantsan

dpe

rceivedair

quality

diffe

redbe

twee

nmaterials;for

somematerials

dilutio

nof

pollutantsby

ventilatio

nis

hardly

possible

Marmor

(197

8)Presen

ceof

air-

cond

ition

ing

redu

cesriskof

mortalitydu

ring

heat

waves

Cross-sectiona

l(re

trospective)

Nursing

home

(n¼

20)

Adults

(n¼

6930

)With

and

with

outair-

conditioning

Noda

taNoda

taNoda

taMortalityrate

v2-te

stHe

atwaves

causesevere

increa

-sesin

mortalityrate

inno

nair-

cond

ition

ednu

rsingho

mes

(risk

ratio

>2)c

ompa

redwith

air-

cond

ition

ednu

rsingho

mes

Narde

llet

al.

(199

1)Th

eoretical

mod

eling

indicatesthat

increa

sing

ventilatio

nmay

redu

cetherate

ofinfections

Cross-sectiona

l;theo

retical

mod

eling

Office

(n¼

1)Ad

ults

(n¼

67)

Mecha

nical

7.5l/(sp)

Rang

e:60

0–15

00pp

m

Noda

taTube

rculin

skin

test

Theo

retical

mod

elling

Themod

elpred

ictedthat

increa

sing

theventilatio

nrate

from

7.5l/(sp)

to12

.5an

d17

.5l/(sp)

wou

ldredu

ceinfections

inoffice

workers

expo

sedto

aco-w

orker

with

cavitary

tube

rculosis

by33

and50

%respectively

Wargocki et al.

118

The outdoor airflow rate of 25 l/s per person isconsiderably higher than the rate of 10 l/s per personbelow which previous reviews suggested that venti-lation affects health (Godish and Spengler, 1996;Mendell, 1993; Menzies and Bourbeau, 1997; Seppa-nen et al., 1999), and is higher than the requirementsin many existing ventilation standards and guidelines(ASHRAE, 1989; CIBSE, 1978; CEN, 1998; ECA,1992). Increasing the ventilation rate to 25 l/s perperson will result in increased first costs and energycosts (if heat recovery systems are not used), thuselevating the costs of running the building. But thehealth-related benefits can surpass the energy costs(Fisk and Rosenfeld, 1997) and an increase inventilation rates may not be required if there isproper control of emission sources indoors. Reducingpollution loads is cheap and effective, and alsoimproves the conditions in indoor environments(Wargocki et al., 1999).The scientific evidence on the effects of ventilation

on health presented in this paper is based on trulymultidisciplinary data as indicated by the wide rangeof journals in which the papers were published(Table 1). Most of the studies were cross-sectional,the observed effects of ventilation on health beingadjusted to control for a number of confoundingfactors in order to obtain reliable results. Adjustingrequires a large number of buildings and largepopulations and can be the source of errors. Theexperimental studies, on the other hand, are self-adjusted as only one factor is changed at a time, allother conditions being kept constant. However,experimental studies require the magnitude of inter-vention to be large enough to have measureableeffects. In a study by Menzies et al. (1993), classifiedas conclusive, the outdoor air supply rate wasmodified to obtain 14 and 30 l/s per person. Butthese rates were only 7 and 32% of the total supplyair rates to offices, the rest being recirculated air.Although the air supply rate was doubled, the changewas still too low to have any significant impact onindoor conditions. Furthermore, the low ventilationrate was already high. This is perhaps why no effectswere observed in this study. In the other twoexperimental studies judged conclusive (Jaakkolaet al., 1991a,b; Wargocki et al., 2000), a positiveeffect of the outdoor air supply rate (range 0–30 l/sper person) on health was observed.The present work indicates a lack of information

on the effects of ventilation on health. Only 30 paperswere judged by the EUROVEN group as providingsufficient scientific evidence on such effects and asmany as 43 were judged to have some deficiencies,making it impossible to draw sound conclusions.Considering that ventilation is a common meansof diluting or removing pollutants indoors, thenumber of conclusive investigations on the effects ofRo

gotet

al.

(199

2)Presen

ceof

air-

cond

ition

ing

redu

cesriskof

mortalitydu

ring

hotwea

ther

Cross-sectiona

l(re

trospective)

Homes

(n¼

noda

ta)

Adults

(n¼

7274

0)With

and

with

out

air-c

onditio

ning

Noda

taNoda

taNoda

taDe

athrate

v2-te

stRisk

ofde

athin

hotwea

ther

42%

lower

inho

mes

with

centrala

ir-cond

ition

ing

compa

redwith

homes

with

out

air-c

onditio

ning

Yaglou

etal.

(193

6)Ve

ntilatio

nrequ

iremen

tsfor

acceptab

leindo

orairqu

ality

inthe

presen

ceof

human

bioe

fflue

nts

Expe

rimen

tCh

ambe

rexpo

sures

Adults

(n¼

185);

pupils

and

children(n

¼97

)

Air-c

onditio

ning

Rang

e:1–

20l/(sp)

Rang

e:65

0–30

00pp

m

Closed

Pane

lof60

untra

ined

judg

esan

doccupa

nts

assessingod

orintensity

Line

arregression

Classicale

xperimen

tals

tudy

sugg

estin

gaventilatio

nrate

of7.5l/(sp)

tocontrolb

ody

odor,a

ssum

ingthat

mod

erateod

orintensity

isacceptab

leforpe

ople

enterin

gindo

orspaces

Yaglou

(195

5)Ve

ntilatio

nrequ

iremen

tsfor

acceptab

leindo

orairqu

ality

inthe

presen

ceof

toba

cco

smoking

Expe

rimen

tCh

ambe

rexpo

sures

Air- cond

ition

ing

(no

recirculation)

3,7,

13,1

7.5

and30

l/spe

rsm

oker

NA

Closed

Pane

lof15

untra

ined

judg

esan

d34

occupa

nts

assessingod

orintensity

Curve

fittin

gAventilatio

nrate

of17

.5–2

0l/s

persm

oker

was

requ

ired

toremoveob

jectiona

bleod

ors;

theinform

ationin

thepa

peris

outdated

becauseof

thefact

that

peop

leareno

wmorecriticalo

fod

orsprod

uced

bytoba

cco

smoke,

asaresultof

increa

sing

societal

concernab

outthe

health

risks

caused

byexpo

sure

totoba

ccosm

oke


119

Table4Su

mmaryof

papers

onassociations

betw

eenhealth,c

omfort

andproductivity

andventilatio

nratesjudged

bythegroupas

conclusive

Paper

Effecta

Results

Design

Buildings

Populatio

nVe

ntilatio

ntype

Outdoorair

supply

rates

CO2

concentra

tion

Windows

Effect

measurement

Data

analysis

Comments

Apte

etal.

(2000)

+Risk

ofSB

Ssymptom

sdecreased

with

decreasing

CO2

concentra

tion

(increasing

ventilatio

nrate)

Cross-

sectional

Office

(n¼

33)

Adults

(n¼

1579)

Mechanical;

air-

conditioning

Not measured

Range:

6–418ppm

(above

outdoor)

Operable;

closed

Self -adm

inistered

questio

nnaire

Multivariate

logistic

regression

Effect

ofventilatio

napproximated

byachange

inCO

2concentra

tion;

adose–response

relatio

nshipbetw

eenSB

Sandventilatio

nindicated

Bluyssen

etal.

(1996)

+Increasing

ventilatio

nrate

improved

perceivedair

quality

Cross-

sectional

Office(n

¼56)

Adults

(n¼

6537)

Alltypes

Range:

0–4.4

l/(sm2

floor)

Average:

673ppm

(above

outdoor)

Operable

(54%

)Ninepanels,

each

with

12–1

5tra

ined

judges

Corre

latio

nDa

taindicate

that

notonly

humansbutalso

building

materials

canbe

asignificant

source

ofpollutantsindoors

Brundage

etal.

(1988)

+Lower

ventilatio

nrate

increasedthe

riskof

acute

respira

tory

disease

Cross-

sectional

Armytra

ining

camps

(n¼

4camps,n

umber

ofbuildings

unknow

n)

Adulttra

inees

(n¼

nodata;

paperbased

on>2.6

mill.

trainee-w

eeks)

Mechanical;

air-c

onditio

n-ingwith

50or

95%

recirculation

0.85

vs.8

.5l/(sp)

(total,

including

recirculation:

3h)

1or

17l/(sp))

Not measured

Operable;

closed

Medical

diagnosis

Multivariate

Theriskof

respira

tory-trans-

mitted

infectionis

increa-

sedam

ongcongregated

immunologically

susceptib

leoccupantsin

tight

buildings

with

low

ventilatio

nrate

Fanger

etal.

(1988)

+Higher

ventilatio

nrate

associated

with

reduced

percentage

dissatisfie

dwith

airquality

Cross-

sectional

Office

(n¼

18);

15offices

and

fiveassembly

halls

Adults

(n¼

not

reporte

d)

Mechanical;

no recirculation

Range:

0.25–6

.09

l/(sm2

floor)(0.2

)5.7h)

1 )

<820 ppm

(above

outdoor)

Operable

Panelo

f54

untra

ined

judges

Data

indicate

that

notonly

humansbutalso

building

materials

canbe

asignificant

source

ofpollutantsindoors

Harving

etal.

(1993)

+Re

ducedventilatio

nrate

increasedthe

concentra

tionof

housedust

mite

sbecauseof

higher

relativehumidity

Cross-

sectional

Home

(n¼

96)

Families

(n¼

96)

with

atleastone

asthmatic

person

Nodata

<0.25vs.

0.25–0

.5vs.>

0.5h)

1

Nodata

Closed

durin

gmeasure-

ments

Medical

diagnosis

ofasthma;

skin

prick

test

for

allergies

v2-te

stExposure

tohousedust

mite

sbecauseof

low

bedroom

ventilatio

nincreasestheriskof

sensitizatio

nandexacer-

batio

nof

allergic

symptom

s

Hoge etal.

(1994)

+Low

ventilatio

nratesand

overcrow

ding

increasedthe

riskof

pneumonia

Cross-

sectional

Jail;

212

cellblocks

Adults

(n¼

6700)

Mechanical;

air-c

onditio

n-ingventila

tionwith

80%

recirculation

Median:

2.9l/(sp);

interquartile

range:

2.1–

4l/(sp)

Meanrange:

1500–2

000ppm

Nodata

Medically

diagnosed

pneumonia

Multivariate

logistic

regression

Inadequate

ventilatio

nassociated

with

pneumococcald

isease

Jaakkola

and

Miettinen

(1995a)

+Risk

forSB

Ssymptom

sincreased

significantly

byaunitdecrease

intheventilatio

nrate

from

25to

0l/s

p

Cross-

sectional

Office

(n¼

14)

Adults

(n¼

399)

Mechanical

(n¼

10);air-

conditioning

(n¼

4);a

llwith

out

recirculation

orhumidi-

fication

<5vs.5

to<15

vs.

15to

<25

vs.>

25l/(sp)

Nodata

Operable;

closed

Self-administered

questio

nnaire

Logistic

regression

Airflow

measured

throughtheexhaustair

outle

tsin

theroom

Wargocki et al.

120

Jaakkola

etal.

(1991a,b)

‚Ch

anging

ventilatio

nratesdidnotchange

theprevalence

ofSB

Ssymptom

s

Cross-

sectional

Office

(n¼

1);

1247

smallo

ffices

Adults

(n¼

968)

Mechanicalw

ithheat

recovery,

with

out

recirculationor

humidificatio

n

Range:

7–70

l/(sp);

mean26

l/(sp)

Mean:

420ppm;

max:9

50ppm

Nodata

Self-administered

questio

nnaire

Multip

lelinear

regression

Noinspectio

nof

heating/

ventilatio

n/airconditio

ning

(HVA

C)system

Jaakkola

etal.

(1991a,b)

+De

creasing

the

ventilatio

nrate

increasedthe

prevalence

ofSB

Ssymptom

s

Experim

ent

Office

(n¼

1);

1247

smallo

ffices

Adults

(n¼

940)

Mechanical

with

heat

recovery,

with

out

recirculation

orhumidi-

fication

0vs.6

vs.1

0vs.2

5l/(sp)

Nodata

Nodata

Self-administered

questio

nnaire

Covaria

nce

Menzie

set

al.

(1993)

‚Ch

ange

ofventilatio

nrates

didnothave

effect

onSB

Ssymptom

s

Experim

ent

Office

(n¼

4)Ad

ults

(n¼

1546)

Mechanical;

air-

conditioning

with

recirculation

14vs.3

0l/(sp)

which

was

only

7and

32%

ofthe

totala

irflow

Mean:

621

vs.8

07ppm

Sealed

Self-admin-

isteredques-

tionnaire

Multivariate

logistic

regression

Changing

theoutdoorair

supply

rate

whenlarge

amountsof

airare

recirculated

(93and

68%)h

asno

effect

onSB

Ssymptom

s

Milton

etal.

(2000)

+Increased

ventilatio

ndecreased

sick-le

ave

Cross-

sectional

Office(n

¼40)

Adults

(n¼

3720)

Air-c

ondi-

tioning

12vs.2

4l/(sp)

800–

900

vs.6

00ppm

Nodata

Short-term

sick

leave

Poisson

regression

controlledfor

covaria

tes

Hourly

employees.

Ventilatio

ncategorized

byan

expert

ratin

gbasedon

CO2

measurements

Norba

cket

al.

(1995)

+At

high

CO2

concentra

tion,

theprevalence

ofnocturnal

breathlessness

was

higher

Case control

Homes

(n¼

88);51%

flats;4

9%single

family

houses

Adults

(n¼

88)

Natural;

mechanical

Not measured

1020 vs.8

50ppm

Operable

Self-adminis-

teredques-

tionnaire

and

clinical

exam

-inationof

asthmaor

atopy

Multip

lelogistic

regression

Nocturnal

breathlessness

isasymptom

ofasthma;

effect

ofventilatio

napproximated

byachange

inCO

2

concentra

tion;

low

ventilatio

nrate

athomeis

ariskforasthmatics

Smedje

etal.

(2000)

+Re

porting

ofat

leastoneasthma-

ticsymptom

was

less

common

with

increasedventilatio

n

Cross-

sectional

School

(n¼

39)

Pupils

6–16

years

old(n

¼1476)

Natural;

mechanical

4.4vs.1

2.8

l/(sp)

(3vs.

4h)

1 )

840 vs.7

80ppm

Nodata

Self-administered

questio

nnaire

posted

to'prim

ary'

parent

Multip

lelogistic

regression;

v2-te

st

77%

ofschoolsdidnot

meetbuildingcode

regulatio

ns

Sundell

etal.

(1994a)

+Risk

ofSB

Ssymptom

sdecreasedwith

increasing

ventilatio

nrate

Cross-

sectional

Office

(n¼

160);

540spaces

Adults

(n¼

4943)

Natural;

mechanical;

with

and

with

out

recirculation

Range:

2–50

l/(sp)

Nodata

Nodata

Self-administered

questio

nnaire

Multivariate

Adose-re

sponse

relatio

nship

was

indicatedbetw

een

increasedventilatio

nrate

anddiminishedriskof

SBSsymptom

s

Sundell

etal.

(1994a,b),

Stenberg

etal.(1994)

+Risk

ofSB

Ssymptom

sdecreasedwith

increasing

ventilatio

nrate

Case control

Office

(n¼

160)

Adults

(n¼

414)

Natural;

mechanical;

with

and

with

out

recirculation

<13.6vs.

>13.6l/(sp)

Nodata

Nodata

Self-administered

questio

nnaire

Multivariate

logistic

regression

13.6

l/(sp)

¼median

ventilatio

nrate

ofthetotal

studypopulatio

n


121

Table4(Contin

ued)

Paper

Effecta

Results

Design

Buildings

Populatio

nVe

ntilatio

ntype

Outdoorair

supply

rates

CO2

concentra

tion

Windows

Effect

measurement

Data

analysis

Comments

Sundell

etal.

(1994c)

+Infestationof

housedust

mite

shigher

with

low

airchange

rates

Case control

Home

(n¼

29)

Natural

Range:

0.1–

0.8h)

1

(2–1

5l/(sp))

Nodata

Operable

House

dust

mite

sallergen

concentra

tion

Linear

regression

Passivesamplingof

ventilatio

nrate;a

causal

linkexists

betw

eenhouse

dust

mite

infestations

and

asthmaandallergies

WIlinder

etal.

(1998)

+Low

ventilatio

nrate

associated

with

reduced

nasalp

atency

andan

infla

mma-

tory

biom

arker

response

ofthe

nasalm

ucosa

Cross-

sectional

School

(n¼

12)

Adults

(school

personnel)

(n¼

234)

Natural;

mechanical

Average:

1.9h)

1(4.4

l/(sp));

Range:

0.5–

5.2h)

1

(1.1–9

l/(sp))

Nodata

Operable

Acoustic

rhinom

etry;

nasallavage

Multip

leregression

Ventilatio

nrate

inl/(sp)

calculated

usingoccupancylevel

Wargocki

etal.

(2000)

+Increasing

venti-

latio

nimproved

perceivedair

quality,reduced

intensity

ofSB

Ssymptom

sand

improved

per-

form

ance

ofofficework

Experim

ent

Officespace

(n¼

1)Female

students

(n¼

30)

Mechanical

3vs.1

0vs.3

0l/(sp)

1266

vs.

477vs.

195ppm

above

outdoor)

Closed

Perceived

airquality,

SBS-symptom

s,perfo

rmance

ofofficetasks

Repeated

measures

Warner

etal.

(2000)

+Installatio

nof

mechanical

ventilatio

nreducedhouse

dust

mite

infestationand

relativehumidity

Case control

Home

(n¼

40)

Children

(n¼

27);

adults

(n¼

13)

Natural;

mechanical

0.4–

0.5h)

1

(with

mechanical

ventilatio

n)

Nodata

Operable

Symptom

s;clinical;p

ulmonary

functio

ns;h

ouse

dust

mite

concentra

tion

Corre

latio

nNomeasurements

ofventilatio

n;acausal

link

exists

betw

eenhouse

dust

mite

infestations

andasthmaand

allergies

Zweers

etal.

(1990)

+Increased

ventilatio

nrate

improved

acceptability

ofodor

Cross-

sectional

Office

(n¼

4);

44spaces

Adults

(n¼

855)

Mechanical

Average:

1.34

h)1 ;

range:

0.9–

2.4h)

1

Nodata

Nodata

Airquality

assessed

by13

trained

judges

Corre

latio

n

Øieet

al.

(1999)

+Low

airchange

rate

increased

riskof

bronchial

obstruction

Case

control

Home

(n¼

172)

Children

(n¼

172)

Natural;

mechanical

‡0.5

vs.

<0.5

h)1 ;

quartiles:6

.9,

11.5,1

7.6

l/(sp)

Nodata

Nodata

Doctor

diagnosed

bronchial

obstruction

Multivariate

Low

ventilatio

nratesstrengthened

the

effectsof

pollutants,

henceindirectly

increasedriskof

bronchialo

bstru

ction

a+¼

increasing

theventilatio

nrate

improves

health,c

omfort

and/or

productivity;‚

¼increasing

theventilatio

nrate

hasno

effect

onhealth,c

omfort

and/or

productivity.

Wargocki et al.

122

Table5Su

mmaryof

papers

onassociations

betw

eenhealth,c

omfort

andproductivity

andventilatio

nsystem

type

andcleanlinessjudged

bythegroupas

conclusive

Paper

Results

Design

Buildings

Populatio

nVe

ntilatio

ntype

Outdoorair

supply

rates

CO2concen-

tratio

nWindows

Effect

measurement

Data

analysis

Comments

Burge

etal.

(1987)

SBSsymptom

sless

prevalentin

naturally

andmechanically

ventilatedbuildings

Cross-

sectional

Office

(n¼

42)

Adults

(n¼

4373)

Natural

(n¼

11)v

s.mechanical(n¼

7)vs.a

ir-conditioning

(n¼

24)

Nodata

Nodata

Operable;

closed

Self-adminis-

tered

questio

nnaire

Multivariate

SBSsymptom

sincreasedsubstantially

once

theairs

upplywas

chilled

orhumidified

Drinka

etal.

(1996)

Presence

ofrecirculation

increasedattack

rates

ofinflu

enza

Cross-

sectional

Nursing

home

(n¼

4)Elderly

adults

(n¼

690)

Mechanicalw

ith0%

(n¼

1),3

0%(n

¼2)

and70%

(n¼

1)recirculation

Nodata

Nodata

Nodata

Medically

diagnosed

influ

enza-A

v2

Fisk

etal.

(1993)

Risk

ofSB

Ssymptom

shigher

inair-c

onditio

ned

comparedwith

naturally

ventilatedbuildings

Cross-

sectional

Office

(n¼

12)

Adults

(n¼

880)

Natural

(n¼

3)vs.

mechanical(n¼

3)vs.a

ir-conditioning

(n¼

6)

Nodata

Range:

370–

580

ppm

Operable;

closed

Self-adminis-

tered

questio

nnaire

Multip

lelogistic

regression

Results

confounded

with

windowsopening,

buildingage;

aspecific

investigationapplying

tomild

climates

and

notgeneralized

for

Nordicclimate

Jaakkola

and

Miettinen

(1995b)

Atendency

forincreased

riskof

SBSsymptom

sin

air-c

onditio

nedbuildings

butnotin

mechanically

ventilatedbuildings

comparedto

naturally

ventilatedbuildings.N

oincreasedriskof

SBS

symptom

sin

air-c

ondi-

tionedbuildings

with

humidificatio

n

Cross-

sectional

Office

(n¼

41)

Adults

(n¼

2678)

Natural

(n¼

7)vs.

mechanical(n¼

20)

vs.a

ir-conditioning

ventilatio

nsystem

(n¼

9with

out

humidificatio

n;n¼

5with

humidificatio

n)

Nodata

Nodata

Operable;

closed

Self-adminis-

tered

questio

nnaire

Multivariate

Mendell

etal.

(1996)

Elevated

prevalence

ofSB

Ssymptom

sin

modern

air-c

onditio

nedbuildings

comparedwith

naturally

ventilatedbuildings

Cross-

sectional

Office

(n¼

12)

Adults

(n¼

880)

Natural

(n¼

3)vs.m

echanical

(n¼

3)vs.

air-c

onditio

ning

(n¼

6)

Nodata

Nodata

Operable;

closed

Self-adminis-

tered

questio

nnaire

Multivariate

logistic

regression

Thesamedata

asreporte

dby

Fisk

etal.(1993)

Sieber

etal.

(1996)

Risk

ofmultip

lelower

respira

tory

system

symptom

sincreased

whendebris

was

observed

inairintake

aswella

swhensystem

shadpoor

drainage

from

drainpans

Cross-

sectional

Office

(n¼

89)

Adults

(n¼

2435)

Air-c

onditio

ning

Nodata

Nodata

Nodata

Self-adminis-

tered

questio

nnaire

Multivariate

logistic

regression

Pollutedair-c

onditio

ning

system

sincreasedrisk

ofSB

Ssymptom

s

Skov etal.

(1990)

Prevalence

ofSB

Ssymptom

sin

buildings

with

supply

air

system

was

higher

comparedwith

naturally

ventilatedbuildings

Cross-

sectional

Office

(n¼

14)

Adults

(n¼

2369)

Natural

vs.

supply

airsystem

Nodata

Average:

800ppm;

range:

500–

1300

ppm

Operable;

closed

Self-adminis-

teredques-

tionnaire

Multivariate

logistic

regression


123

ventilation on health is very small and more scientificdata would be useful. This concerns especially schoolsand homes where fewest studies were carried out.Reviewed articles showed very poor conditionsindoors, especially as regards ventilation in schools,many of which had ventilation rates far below therequirements in ventilation guidelines and standards(Smedje and Norback, 2000). This creates conditionsthat can exacerbate allergies among children, consid-ering in addition that many homes are poorlyventilated (Harving et al., 1993; Norback et al.,1995; Smedje and Norback, 2000; Sundell et al.,1994c). Data on health outcomes other than self-reported SBS symptoms used in the majority of thestudies reviewed would also be useful.It is important for future investigations to deter-

mine why occupants of air-conditioned buildingssuffer more often from SBS symptoms than occu-pants in naturally or mechanically ventilated build-ings. This has been found when analyzing the studiesjudged conclusive by the present work (Table 5) aswell as in previous reviews (Mendell and Smith, 1990;Menzies and Bourbeau, 1997). Naturally ventilatedbuildings are generally older and constructed fromtraditional building materials compared with air-conditioned buildings. This can result in lowerpollution loads in naturally ventilated buildings.Furthermore, it is usual to open windows in naturallyventilated buildings located in mild climates and thiscan increase ventilation rates considerably. These twofactors may provide some explanation to theobserved association; however, most of the studiesin which this association was observed did notmeasure the actual ventilation rates in the buildingsinvestigated (Table 5). Another possible reason forthe observed association can be the complexity of air-conditioning systems and thus a higher probability offailures, as well as improper maintenance resulting indirty filters, ducts, or water reservoirs. A pollutedHVAC system can increase the risk of SBS symp-toms, as shown in a study of Sieber et al. (1996).Furthermore, an increased ventilation rate in pollutedsystems can increase pollution from the HVACcomponents (Bjorkroth et al., 1998) and eventuallydiminish the benefits of an increased outdoor airsupply rate. In general, there is a lack of dataallowing sound comparisons to be made of naturally,mechanically, and air-conditioned buildings; there isan urgent need for more studies in these buildings,including subjective measurements and sufficientcharacterization of indoor climate.Most of the studies reviewed were not carried out in

summer, thereby disregarding the thermal benefits ofair-conditioning. During the summer season, buildingswith air-conditioning have the obvious advantage ofbeing able to maintain thermal comfort and goodperceived air quality by controlling the indoor airTa

ble5(Contin

ued)

Paper

Results

Design

Buildings

Populatio

nVe

ntilatio

ntype

Outdoorair

supply

rates

CO2concen-

tratio

nWindows

Effect

measurement

Data

analysis

Comments

Sundell

etal.

(1994a)

Noincreasedriskof

SBS

symptom

sin

mechanically

ventilated

buildings.N

oincreased

riskof

SBSsymptom

sin

thepresence

ofrecirculation

Cross-

sectional

Office

(n¼

160);

540spaces

Adults

(n¼

4943)

Natural

(2%);

mechanical;with

recirculation(24%

)andwith

out

recirculation(74%

)

Range:

2–50

l/(sp)

Nodata

Nodata

Self-adminis-

tered

questio

nnaire

Multivariate

Zweers

etal.

(1992)

SBSsymptom

prevalence

higher

inair-c

onditio

ned

buildings

comparedto

naturally

and

mechanically

ventilatedbuildings

Cross-

sectional

Office

(n¼

61)

Adults

(n¼

7043)

Natural

(n¼

21)v

s.mechanical(n¼

15)

vs.a

ir-conditioning

(n¼

25)

Nodata

Average:

730ppm;

range:

485–

1329

ppm

63% operable

Self-adminis-

tered

questio

nnaire

Multip

lelogistic

regression

Wargocki et al.

124

temperature and humidity. The benefits of air-condi-tioning in extremely hot conditions have been indicatedin studies in nursing homes (Marmor, 1978) and inordinary households (Rogot et al., 1992) where thepresence of air-conditioning significantly reduced therisk of mortality compared with buildings without air-conditioning.Another possible artifact in many studies reviewed

was the assumption that clean outdoor air was used forventilation and that HVAC systems were clean. Infuture experiments some way of assessing cleanliness ofoutdoor and supplied air and cleanliness of HVACsystems would be useful.

Conclusions (consensus statement)

The following consensus was reached by the EUROV-EN group:

• The literature shows a strong association betweenventilation and comfort (as indicated by perceivedair quality) and health (as indicated by SBS symp-toms, inflammation, infections, asthma, allergy,short-term sick leave). It also indicates that there isan association between ventilation rate and produc-tivity (as indicated by performance of office work).

• The literature indicates that outdoor air rates below25 l/s per person in offices increase the risk ofSBS symptoms, increase short-term sick leave, anddecrease productivity. They also suggest that thesame may apply for schools but little information onthis aspect is available at present.

• The literature indicates that air change rates above0.5 h)1 in homes reduce the degree of infestation ofhouse dust mites in Nordic countries. Taking intoaccount the causal link between house dust mitesinfestation and asthma and allergies, these datasuggest that decreased ventilation may exacerbateallergies.

• The literature indicates that occupants of manybuildings with air-conditioning systems may havean increased risk of SBS symptoms compared withoccupants in naturally or mechanically ventilatedbuildings, implying thus that new ways of condi-tioning the air may be required. These results could

be confounded by a number of factors such asimproper maintenance of HVAC systems (the morecomplex the system the more liable it is to fail),building age (new types of building material arelikely to be found in air-conditioned buildingserected in the past 30 years), and unknown factorssuch as window opening. The studies were fur-thermore carried out mainly in transient and coldseasons, without taking into account the thermalbenefits of air-conditioning in hot seasons.

• The literature shows that improper maintenance,design, and functioning of HVAC systems contri-butes to an increased prevalence of SBS symptoms.This indicates a need for safety factors and propermaintenance of ventilation systems, including suchaspects as appropriate distance separating the inletand exhaust, replacing dirty filters, cleaning ducts,and the prevention of water reservoirs and water inthe systems.

• The literature shows that pollution sources otherthan the pollutants emitted by humans (bioefflu-ents) are important indoors. Consequently, propersource control is required in the first place, andsecondly the design of ventilation rates based on allpollution loads present indoors.

• The present work indicates the gaps where know-ledge is lacking as regards the effects of ventilationon human health, comfort, and productivity. Moreinformation is required on links between ventilationrates and health in schools and homes, and on theassociation between type of ventilation system andhealth effects.

Acknowledgments

The present work has been supported by EuropeanCommission in the framework of programmes andactions in the health and consumer protection sectorsSANCO through Grant Agreement No. SI2.142318(99CVF2-608) to the National Institute of PublicHealth in Sweden. Many thanks are due to MonaLakso who acted as an administrative secretary for thework and a contact person to EU, and whose assist-ance has been crucial for the project.

References

Andersen, I. and Korsgaard, J. (1986) Asth-ma and the indoor environment. Assess-ment of the health implications of highindoor humidity, Environ. Int., 12, 121–127.

ASHRAE (1989) Standard 62-89: Ventilationfor Acceptable Indoor Air Quality, Atlan-ta, GA, American Society of HeatingRefrigerating and, Air-ConditioningEngineers, Inc.

ASHRAE (1993) ASHRAE Handbook –Fundamentals, Atlanta, GA,American Society of Heating, Refriger-ating and, Air-Conditioning Engineers,Inc.

CEN (1998) Technical Report CR 1752:Ventilation for Buildings: Design Criteriafor the Indoor Environment, Brussels,European Committee for Standardiza-tion.

CIBSE (1978) CIBSE Guide Section A1,Environmental Criteria for Design,London, The Chartered Institution ofBuilding Services Engineers.

European Collaborative Action Indoor AirQuality and its Impact on Man (ECA)(1992) Guidelines for Ventilation Require-ments in Buildings, Luxembourg, Office forPublications of the European Communi-ties, Report No. 11 (EUR 14449 EN).


125

Fisk, W.J. and Rosenfeld, A.H. (1997) Esti-mates of improved productivity andhealth from better indoor environments,Indoor Air, 7, 158–172 (Errata, IndoorAir, 8 (1998), 301).

Godish, T. and Spengler, J.D. (1996) Rela-tionships between ventilation and indoorair quality: a review, Indoor Air, 6, 135–145.

Mendell, M.J. (1993) Non-specific symptomsin office workers: a review and summaryof the epidemiologic literature, IndoorAir, 3, 227–236.

Mendell, M.J. and Smith, A.H. (1990) Con-sistent pattern of elevated symptoms inair-conditioned office buildings:a reanalysis of epidemiologic studies, Am.J. Pub. Health, 80, 1193–1199.

Menzies, D. and Bourbeau, J. (1997) Build-ing-related illnesses, New Engl. J. Med.,337, 1524–1531.

Seppanen, O.A., Fisk, W.J. and Mendell,M.J. (1999) Association of ventilationrates and CO2-concentrations with healthand other responses in commercial andinstitutional buildings, Indoor Air, 9, 226–252.

Sundell, J. and Bornehag, C.-G. (1999)Nordic interdisciplinary reviews of thescientific literature concerning the rela-tionship between indoor environmentalfactors and health, Nordworks. In: Raw,G., Aizlewood, C. and Warren, P. (eds)Proceedings of Indoor Air ¢99, Edinburgh,the 8th International Conference onIndoor Air Quality and Climate, Vol. 1,pp. 177–182.

Wargocki, P., Wyon, D.P., Baik, Y.K.,Clausen, G. and Fanger, P.O. (1999)Perceived air quality, Sick BuildingSyndrome (SBS) symptoms and pro-ductivity in an office with two differentpollution loads, Indoor Air, 9, 165–179.

World Health Organization (WHO) (1948)The Constitution of World Health Organ-ization, Geneva, WHO.

Papers reviewed by the EUROVEN groupAbbritti, G., Muzi, G., Accattoli, M.P.,Fiordi, T., dell’Omo, M., Colangeli, C.,Gabrielli, A.R., Fabbri, T. and d’Aless-andro, A. (1992) High prevalence of sickbuilding syndrome in a new air-condi-tioned building in Italy, Arch. Environ.Health, 47, 16–22.

Apte, M.G., Fisk, W.J. and Daisey, J.M.(2000) Associations between indoor CO2concentrations and sick building syn-drome symptoms in US office buildings:an analysis of the 1994–1996 BASE studydata, Indoor Air, 10, 246–257.

Bachmann, M., Turck, W. and Myers, J.(1995) Sick building symptoms in officeworkers: a follow-up study before andone year after changing buildings, Occup.Med., 45, 11–15.

Beck, H.I., Bjerring, P. and Harving, H.(1989) Atopic dermatitis and the indoorclimate. The effect from preventivemeasures, Acta Derm. Venereol., 69, 162–165.

*Berardi, B.M., Leoni, E., Marchesini, B.,Cascella, D. and Raffi, G.B. (1991)Indoor climate and air quality in newoffices: effects of a reduced air-exchangerate, Int. Arch. Occup. Environ. Health,63, 233–239.

Berg-Munch, B., Clausen, B.G. and Fanger,P.O. (1986) Ventilation requirements forthe control of body odor in spaces occu-pied by women, Environ. Int., 12, 195–199.

Bjorkroth, M., Seppanen, O. and Torkki, A.(1998) Chemical and sensory emissionsfrom HVAC components and ducts. In:Moschandreas, D. (ed.) Design, Con-struction and Operation of Healthy Build-ings – Solutions to Global and RegionalConcerns, ASHRAE, 47–55.

Bluyssen, P.M., de Oliveira Fernandes, E.,Groes, L., Clausen, G., Fanger, P.O.,Valbjørn, O., Bernhard, C.A. and Roulet,C.A. (1996) European indoor air qualityaudit project in 56 office buildings, IndoorAir, 6, 221–238.

Bourbeau, J., Brisson, C. and Allaire, S.(1996) Prevalence of the sick buildingsyndrome symptoms in office workersbefore and after being exposed to abuilding with an improved ventilationsystem, Occup. Environ. Med., 53, 204–210.

Bourbeau, J., Brisson, C. and Allaire, S.(1997) Prevalence of the sick buildingsyndrome symptoms in office workersbefore and six months and three yearsafter being exposed to a building with animproved ventilation system, Occup.Environ. Med., 54, 49–53.

Brundage, J.F., Scott, R.M., Lednar,W.M., Smith, D.W. and Miller, R.N.(1988) Building-associated risk of feb-rile acute respiratory diseases in Armytrainees, J. Am. Med. Assoc., 259, 2108–2112.

Burge, S., Hedge, A., Wilson, E., Bass, J.H.and Robertson, A. (1987) Sick Buildingsyndrome: a study of 4,373 office work-ers, Ann. Occup. Hyg., 31, 493–504.

Cain, W., Leaderer, R., Isseroff, L., Bergl-und, R., Huey, E., Lipsitt, E. and Perl-mann, D. (1983) Ventilation requirementsin buildings – I. Control of occupancyodor and tobacco smoke, Atmos. Envi-ron., 17, 1183–1197.

*Dale, H.C.A. and Smith, P. (1985) Bed-room ventilation: attitudes and policies,Energy Res., 9, 431–439.

Drinka, P.J., Krause, P., Schilling, M., Mil-ler, B.A., Shult, P. and Gravenstein, S.(1996) Report of an outbreak: nursinghome architecture and influenza-Aattack rates, J. Am. Geriatr. Soc., 44, 910–913.

Everett, W.D. and Kipp, H. (1991) Epi-demiologic observations of operatingroom infections resulting from variationsin ventilation and temperature, Am.J. Infect. Control, 19, 277–282.

Fanger, P.O. (1988) Introduction to the olfand the decipol units to quantify air pol-lution perceived indoors and outdoors,Energy and Buildings, 12, 1–6.

Fanger, P.O., Lauridsen, J., Bluyssen, P. andClausen, G. (1988) Air pollution sourcesin offices and assembly halls, quantifiedby the olf unit, Energy and Buildings, 12,7–19.

Finnegan, M.J., Pickering, C.A. and Burge,P.S. (1984) The sick building syndrome:prevalence studies, Br. Med. J., 289,1573–1575.

Fisk, W.J., Mendell, M.J., Daisey, J.M.,Faulkner, D., Hodgson, A.T., Nematol-lahi, M. and Macher, J.M. (1993) Phase 1of the California healthy building study,Indoor Air, 4, 246–254.

Gibert, I., Chevalier, A. and Lambrozo, J.(1992) No difference in rates of absen-teeism between workers in air-condi-tioned offices and naturally ventilatedones: a data base study, Indoor Environ-ment, 1, 279–284.

Gunnarsen, L. (1997) The influence of area-specific ventilation rate on emission fromconstruction products, Indoor Air, 7, 116–120.

*Gustafsson, D., Andersson, K., Fagerlund,I. and Kjellman, N.I. (1996) Significanceof indoor environment for the develop-ment of allergic symptoms in childrenfollowed up to 18 months of age, Allergy,51, 789–795.

Haghighat, F. and Donnini, G. (1999)Impact of psycho-social factors on per-ception of the indoor air environmentstudies in 12 office buildings, Building andEnvironment, 34, 479–503.

*Harrison, J., Pickering, C.A., Faragher,E.B., Austwick, P.K., Little, S.A. andLawton, L. (1992) An investigation of therelationship between microbial and par-ticulate indoor air pollution and the sickbuilding syndrome, Resp. Med., 86, 225–235.

Harving, H., Korsgaard, J. and Dahl, R.(1993) House-dust mites and associatedenvironmental conditions in Danishhomes, Allergy, 48, 106–109.

Harving, H., Korsgaard, J. and Dahl, R.(1994) Clinical efficacy of reduction inhouse-dust mite exposure in specially de-signed, mechanically ventilated ‘‘healthy’’homes, Allergy, 49, 866–870.

*Hedge, A. (1984) Evidence of a relationshipbetween office design and self-reports ofill health among office workers in theUnited Kingdom, J. Arch. Plann. Res., 1,163–174.

Hedge, A., Burge, P.S., Robertson, A.S.,Wilson, S. and Harris-Bass, J. (1989)Work-related illness in offices: a proposed

Wargocki et al.

126

model of the �Sick Building Syndrome�,Environ. Int., 15, 143–158.

Hedge, A., Erickson, W.A. and Rubin, G.(1995) Individual and occupational cor-relates of sick building syndrome, IndoorAir, 5, 10–21.

Hedge, A., Erickson, W.A. and Rubin, G.(1996) Predicting sick building syndromeat the individual and aggregate levels,Environ. Int., 22, 3–19.

Hill, B.A., Craft, B.F. and Burkart, J.A.(1992) Carbon dioxide, particulates, andsubjective human responses in officebuildings without histories of indoor airquality problems, Appl. Occup. Environ.Hyg., 7, 101–111.

*Hoffman, R.E., Wood, R.C. and Kreiss, K.(1993) Building-related asthma in Denveroffice workers, Am. J. Public Health, 83,89–93.

Hoge, C.W., Reichler, M.R., Dominguez,E.A., Bremer, J.C., Mastro, T.D., Hend-ricks, K.A., Musher, D.M., Elliott, J.A.,Facklam, R.R. and Breiman, R.F.(1994) An epidemic of pneumococcaldisease in an overcrowded, inadequatelyventilated jail, New Engl. J. Med., 331,643–648.

Hosein, H.R., Corey, P. and Robertson, J.M.(1989) The effect of domestic factors onrespiratory symptoms and FEV1, Int. J.Epidemiol., 18, 390–396.

*Ihenacho, H.N. (1990) Air-conditioningand health: effect on pulse and bloodpressure of young healthy, Nigerians,Central African J. Med., 36, 147–150.

Iversen, M., Bach, E. and Lundqvist, G.R.(1986) Health and comfort changesamong tenants after retrofitting oftheir housing, Environ. Int., 12, 161–166.

Iwashita, G., Kimura, K., Tanabe, S., Yos-hizawa, S. and Ikeda, K. (1990) Indoorair quality assessment based on humanolfactory sensation, J. Arch. Plann. Envi-ron. Eng., 410, 9–19.

Jaakkola, J.J. and Miettinen, P. (1995a)Ventilation rate in office buildings andsick building syndrome, Occup. Environ.Med., 52, 709–714.

Jaakkola, J.J. and Miettinen, P. (1995b)Type of ventilation system in officebuildings and sick building syndrome,Am. J. Epidemiol., 141, 755–765.

Jaakkola, J.J.K., Reinikainen, L.M., Hei-nonen, O.P., Majanen, A. and Seppanen,O. (1991a) Indoor air requirements forhealthy office buildings: recommenda-tions based on epidemiologic study,Environ. Int., 17, 371–378.

Jaakkola, J.J.K., Heinonen, O.P. andSeppanen, O. (1991b) Mechanical venti-lation in office buildings and the sickbuilding syndrome: an experimental andepidemiological study, Indoor Air, 1, 111–121.

Jaakkola, J.J.K., Tuomaala, P. and Seppa-nen, O. (1994) Air recirculation and sick

building syndrome: blinded cross-overtrial, Am. J. Pub. Health, 84, 422–428.

*Kelland, P. (1992) Sick building syndrome,working environments and hospital staff,Indoor Environ, 1, 335–340.

Knudsen, H.N., Clausen, G. and Fanger,P.O. (1997) Sensory characterization ofemissions from materials, Indoor Air, 7,107–115.

Knudsen, H.N., Valbjørn, O. and Nielsen,P.A. (1998) Determination of exposure–response relationships for emissions frombuilding products, Indoor Air, 8, 264–275.

Kodama, A.M. and McGee, R.I. (1986)Airborne microbial contaminants in in-door environments, Naturally ventilatedand air-conditioned homes, Arch. Envi-ron. Health, 41, 306–311.

Kroeling, P. (1988) Health and well-beingdisorders in air-conditioned buildings;comparative investigations of the �build-ing illness� syndrome, Energy and Build-ings, 11, 277–282.

Marmor, M. (1978) Heat wave mortality innursing homes, Environ. Res., 17, 102–115.

*McDonald, J.C., Armstrong, B., Benard, J.,Cherry, N.M. and Farant, J.P. (1993)Sick building syndrome in a Canadianoffice complex, Arch. Environ. Health, 48,298–304.

Mendell, M.J., Fisk, W.J., Deddens, J.A.,Seavey, W.G., Smith, A.H., Smith, D.F.,Hodgson, A.T., Daisey, J.M. and Gold-man, L.R. (1996) Elevated symptom pre-valence associated with ventilation type inoffice buildings, Epidemiology, 7, 583–589.

*Menzies, D., Tamblyn, R.M., Nunes, F.,Hanley, J. and Tamblyn, R.T. (1996)Exposure to varying levels of contami-nants and symptoms among workers intwo office buildings, Am. J. Pub. Health,86, 1629–1633.

Menzies, D., Pasztor, J., Nunes, F., Leduc, J.and Chan, C.H. (1997) Effect of a newventilation system on health and well-being of office workers, Arch. Environ.Health, 52, 360–367.

Menzies, R., Tamblyn, R., Farant, J.P.,Hanley, J., Nunes, F. and Tamblyn, R.(1993) The effect of varying levels ofoutdoor-air supply on the symptoms ofsick building syndrome, New Engl. J.Med., 328, 821–827.

*Merrill, J.L. and TenWolde, A. (1989)Overview of moisture-related damage inone group of Wisconsin manufacturedhouses, ASHRAE Trans., 95, Part, 1,405–414.

Milton, D., Glencross, P. and Walters, M.(2000) Risk of sick-leave associated withoutdoor air supply rate, humidificationand occupants complaints, Indoor Air, 10,212–221.

Muzi, G., Abbritti, G., Accattoli, M.P.and dell’Omo, M. (1998) Prevalence ofirritative symptoms in a nonproblem

air-conditioned office building, Int. Arch.Occup. Environ. Health, 71, 372–378.

Nardell, E.A., Keegan, J., Cheney, S.A. andEtkind, S.C. (1991) Airborne infection.Theoretical limits of protection achiev-able by building ventilation, Am. Rev.Resp. Dis., 144, 302–306.

Nelson, N.A., Kaufman, J.D., Burt, J. andKarr, C. (1995) Health symptoms and thework environment in four non-problemUnites States office buildings, Scand.J. Work Environ. Health, 21, 51–59.

Norback, D. (1995) Subjective indoor airquality in schools – the influence of highroom temperature, carpeting, fleecy wallmaterials, and volatile organic com-pounds (VOC), Indoor Air, 5, 237–246.

Norback, D. and Edling, C. (1991) Envi-ronmental, occupational, and personalfactors related to the sick building syn-drome in the general population, Br.J. Industr. Medicine, 48, 451–462.

Norback, D., Bjornsson, E., Janson, C.,Widstrom, J. and Boman, G. (1995)Asthmatic symptoms and volatile organiccompounds, formaldehyde, and carbondioxide in dwellings, Occup. Environ.Med., 52, 388–395.

Norback, D., Michel, I. and Widstrom, J.(1990a) Indoor air quality and personalfactors related to the sick building syn-drome, Scand. J. Work Environ. Health,16, 121–128.

Norback, D., Torgen, M. and Edling, C.(1990b) Volatile organic compounds,respirable dust, and personal factorsrelated to prevalence and incidence of sickbuilding syndrome in primary schools, Br.J. Industr. Med., 47, 733–741.

Nordstrom, K., Norback, D. and Akselsson,R. (1995a) Subjective indoor air quality inhospitals – The influence of building age,ventilation flow, and personal factors,Indoor Environ., 4, 37–44.

Nordstrom, K., Norback, D. and Akselsson,R. (1995b) Influence of indoor air qualityand personal factors on the sick buildingsyndrome (SBS) in Swedish geriatrichospitals, Occup.Environ. Med., 52, 170–176.

Øie, L., Nafstad, P., Botten, G., Magnus, P.and Jaakkola, J.K. (1999) Ventilation inhomes and bronchial obstruction inyoung children, Epidemiology, 10, 294–299.

*Paul, W.S., Moore, P.S., Karabatsos, N.,Flood, S.P., Yamada, S., Jackson, T. andTsai, T.F. (1993) Outbreak of Japaneseencephalitis on the island of Saipan, 1990,J. Infect. Dis., 167, 1053–1058.

Pejtersen, J., Brohus, H., Hyldgaard, C.E.,Nielsen, J.B., Valbjørn, O., Hauschildt,P., Kjærgaard, S.K. and Wolkoff, P.(2001) Effect of renovating an officebuilding on occupants’ comfort andhealth, Indoor Air, 11, 10–25.

*Richards, A.L., Hyams, K.C., Watts, D.W.,Rozmajzl, P.J., Woody, J.N. and Merrel,


127

B.R. (1993) Respiratory disease amongmilitary personnel in Saudi Arabia duringOperation Desert Shield, Am. J. Pub.Health, 83, 1326–1329.

Robertson, A.S. (1989) Building sickness –are symptoms related to office lightning?,Ann. Occup. Hyg., 33, 47–59.

Robertson, A.S., Burge, P.S., Hedge, A.,Sims, J., Gill, F.S., Finnegan, M., Pic-kering, C.A. and Dalton, G. (1985)Comparison of health problems relatedto work and environmental measurementsin two office buildings with differentventilation systems, Br. Med. J., 10,373–376.

Rogot, E., Sorlie, P.D. and Backlund, E.(1992) Air-conditioning and mortality inhot weather, Am. J. Epidemiol., 136, 106–116.

Rowe, D., Wilke, S. and Guan, L. (1993)Examination of sick leave absencesfrom work in buildings with various ratesof ventilation, Indoor Environ., 2, 276–284.

Ruotsalainen, R., Jaakkola, J.J.K., Ronn-berg, R., Majanen, A. and Seppanen, O.(1991) Symptoms and perceived indoorair quality among occupants of housesand apartments with different ventilationsystems, Indoor Air, 1, 428–438.

Ruotsalainen, R., Jaakkola, N. and Jaakko-la, J.J.K. (1994) Ventilation rate as a de-terminant of symptoms and perceivedodors among workers in daycare centers,Environ. Int., 20, 731–737.

*Salisbury, S.A. (1984) A typically frustra-ting building investigation, Ann. Am.Conf. Governmental Industrial Hygienists,10, 129–130.

*Shigematsu, I. and Minowa, M. (1985)Indoor infection in a modern building,Tokai J. Exp. Clin. Med., 10, 407–413.

Sieber, W.K., Stayner, L.T., Malkin, R.,Petersen, M.R., Mendell, M.J., Walling-ford, K.M., Crandall, M.S., Wilcox, T.G.and Reed, L. (1996) The National Insti-tute for Occupational Safety and Healthindoor environmental evaluation experi-ence, Part three: Associations betweenenvironmental factors and self-reportedhealth conditions, Appl. Occup. Environ.Hyg., 11, 1387–1392.

Skov, P. and Valbjørn, O. (1987) The sickbuilding syndrome in the office environ-ment: The Danish Town Hall study,Environ. Int., 13, 339–349.

Skov, P., Valbjørn, O. and Pedersen, B.V.(1990) Influence of indoor climate on thesick building syndrome in an office envi-ronment, Scand. J. Work Environ. Health,16, 363–371.

Smedje, G. and Norback, D. (2000) Newventilation systems at select schools inSweden – effects on asthma and exposure,Arch. Environ. Health, 55, 18–25.

Smedje, G., Norback, D. and Edling, C.(1997) Subjective indoor air quality inschools in relation to exposure, IndoorAir, 7, 143–150.

Stenberg, B., Eriksson, N., Hoog, J.,Sundell, J. and Wall, S. (1994) The SickBuilding Syndrome (SBS) in office work-ers. A case-referent study of personal,psychosocial and building-related riskindicators, Int. J. Epidemiol., 23, 1190–1197.

Stenberg, B., Eriksson, N., Mild, K.H.,Hoog, J., Sandstrom, M., Sundell, J.and Wall, S. (1995) Facial skin symp-toms in visual display terminal workers(VDT). A case-referent study of personal,psychosocial, building- and VDT-relatedrisk indicators, Int. J. Epidemiol., 24, 796–803.

Sterling, E. and Sterling, T. (1983) The im-pact of different ventilation levels andfluorescent lighting types on building ill-ness: an experimental study, Can. J. Pub.Health, 74, 385–392.

*Sullivan-Bolyai, J.Z., Lumish, R.M., Smith,E.W., Howell, J.T., Bregman, D.J., Lund,M., Page, R.C. and Page, R.C. (1979)Hyperpyrexia due to air-conditioningfailure in a nursing home, Public HealthRep., 94, 466–470.

Sundell, J., Lindvall, T. and Stenberg, B.(1994a) Associations between type ofventilation and air flow rates in officebuildings and the risk of SBS-symptomsamong occupants, Environ. Int., 20, 239–251.

Sundell, J., Lindvall, T., Stenberg, B. andWall, S. (1994b) Sick Building Syndrome(SBS) in office workers and facial skinsymptoms among VDT-workers in rela-tion to building and room characteristics:two case-referent studies, Indoor Air, 4,83–94.

Sundell, J., Wickman, M., Pershagen, G. andNordvall, S.L. (1994c) Ventilation inhomes infested by house-dust mites,Allergy, 50, 106–112.

*Tamblyn, R.M., Menzies, R.I., Tamblyn,R.T., Farant, J.P. and Hanley, J. (1992)The feasibility of using a double blindexperimental cross-over design to studyinterventions for sick building syndrome,J. Clin. Epidemiol., 45, 603–612.

Teculescu, D.B., Sauleau, E.A., Massin, N.,Bohadana, A.B., Buhler, O., Benamghar,L. and Mur, J.M. (1998) Sick-buildingsymptoms in office workers in north-eastern France: a pilot study, Int.Arch. Occup. Environ. Health, 71, 353–356.

*Turiel, I., Hollowell, C.D., Miksch, R.R.,Rudy, J.V., Young, R.A. and Coye, M.J.(1983) Effects of reduced ventilation onindoor air quality in an office building,Atmos. Environ., 17, 51–64.

Vincent, D., Annesi, I., Festy, B. andLambrozo, J. (1997) Ventilation system,indoor air quality, and health outcomes inParisian modern office workers, Environ.Res., 75, 100–112.

Walinder, R., Norback, D., Wieslander, G.,Smedje, G. and Erwall, C. (1997a) Nasalcongestion in relation to low air exchangerate in schools. Evaluation by acousticrhinometry, Acta Otolaryngol., 117, 724–727.

Walinder, R., Norback, D., Wieslander, G.,Smedje, G. and Erwall, C. (1997b) Nasalmucosal swelling in relation to low airexchange rate in schools, Indoor Air, 7,198–205.

Walinder, R., Norback, D., Wieslander, G.,Smedje, G., Erwall, C. and Venge, P.(1998) Nasal patency and biomarkers innasal lavage – the significance of air ex-change rate and type of ventilation inschools, Int. Arch. Occup. Environ.Health, 71, 479–486.

Wargocki, P., Wyon, D.P., Sundell, J.,Clausen, G. and Fanger, P.O. (2000)The effects of outdoor air supply ratein an office on perceived air quality,Sick Building Syndrome (SBS) symp-toms and productivity, Indoor Air, 10,222–236.

Warner, J.A., Frederick, J.M., Bryant, T.N.,Wiech, C., Raw, G.J., Hunter, C., Ste-phen, F.R., McIntyre, D.A. and Warner,J.O. (2000) Mechanical ventilation andhigh-efficiency vacuum cleaning: a com-bined strategy of mite and mite allergenreduction in the control of mite-sensitiveasthma, J. Allergy Clin. Immunol., Part 1,105, 75–82.

Wieslander, G., Norback, D., Walinder, R.,Erwall, C. and Venge, P. (1999) Inflam-mation markers in nasal lavage, and nasalsymptoms in relation to relocation to anewly painted building: a longitudinalstudy, Int. Arch. Occup. Environ. Health,72, 507–515.

Wyon, D.P. (1992) Sick buildings and theexperimental approach, Environ. Tech-nol., 13, 313–322.

Yaglou, C.P. (1955) Ventilation require-ments for cigarette smoke, ASHAETransactions, 61, 25–32.

Yaglou, C.P., Riley, E.C. and Coggins, D.I.(1936) Ventilation requirements, ASH-RAE Trans., 42, 133–162.

Zweers, T., Skov, P., Valbjørn, O. andMølhave, L. (1990) The effect of ventila-tion and air pollution on perceived indoorair quality in five town halls, Energy andBuildings, 14, 175–181.

Zweers, T., Preller, L., Brunekreef, B. andBoleij, J.S.M. (1992) Health and indoorcomplaints of 7043 office workers in 61buildings in the Netherlands, Indoor Air,2, 127–136.

Wargocki et al.

128

Documents

Ventilation and health in non-industrial indoor environments: report from a European Multidisciplinary Scientific Consensus Meeting (EUROVEN)