Full text of DOI:10.1080/10473289.2001.10464251

This article was downloaded by: [York University Libraries]
On: 13 August 2014, At: 05:18
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Journal of the Air & Waste Management Association
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/uawm20
Personal Exposure Levels and Microenvironmental
Concentrations of Formaldehyde and Acetaldehyde in
the Helsinki Metropolitan Area, Finland
Jouni Jurvelin a , Matti Vartiainen a , Matti Jantunen a & Pertti Pasanen b
a Division of Environmental Health , KTL-National Public Health Institute , Kuopio , Finland
b Department of Environmental Sciences , University of Kuopio , Kuopio , Finland
Published online: 27 Dec 2011.
To cite this article: Jouni Jurvelin , Matti Vartiainen , Matti Jantunen & Pertti Pasanen (2001) Personal Exposure Levels and
Microenvironmental Concentrations of Formaldehyde and Acetaldehyde in the Helsinki Metropolitan Area, Finland, Journal of
the Air & Waste Management Association, 51:1, 17-24, DOI: 10.1080/10473289.2001.10464251
To link to this article: http://dx.doi.org/10.1080/10473289.2001.10464251
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

TECHNICAL PAPER
Jurvelin et al.
ISSN 1047-3289 J. Air & Waste Manage. Assoc. 51:17-24
Copyright 2001 Air & Waste Management Association
Personal Exposure Levels and Microenvironmental
Concentrations of Formaldehyde and Acetaldehyde in
the Helsinki Metropolitan Area, Finland
Jouni Jurvelin, Matti Vartiainen, and Matti Jantunen
Division of Environmental Health, KTL-National Public Health Institute, Kuopio, Finland
Pertti Pasanen
Department of Environmental Sciences, University of Kuopio, Kuopio, Finland
ABSTRACT
exposures. Correlation between formaldehyde and acetal-
Personal 48-hr exposures to formaldehyde and acetalde-
hyde of 15 randomly selected participants were measured
during the summer/autumn of 1997 using Sep-Pak DNPH-
Silica cartridges as a part of the EXPOLIS study in Helsinki,
Finland. In addition to personal exposures, simultaneous
measurements of microenvironmental concentrations
were conducted at each participant’s residence (indoor
and outdoor) and workplace. Mean personal exposure lev-
els were 21.4 ppb for formaldehyde and 7.9 ppb for ac-
etaldehyde. Personal exposures were systematically lower
than indoor residential concentrations for both com-
pounds, and ambient air concentrations were lower than
both indoor residential concentrations and personal ex-
posure levels. Mean workplace concentrations of both
compounds were lower than mean indoor residential con-
centrations. Correlation between personal exposures and
indoor residential concentrations was statistically signifi-
cant for both compounds. This indicated that indoor resi-
dential concentrations of formaldehyde and acetaldehyde
are a better estimate of personal exposures than are con-
centrations in ambient air. In addition, a time-weighted
exposure model did not improve the estimation of per-
sonal exposures above that obtained using indoor resi-
dential concentrations as a surrogate for personal
dehyde was statistically significant in outdoor microen-
vironments, suggesting that both compounds have similar
sources and sinks in ambient urban air.
INTRODUCTION
The two most abundant aldehydes in ambient air—form-
aldehyde and acetaldehyde—are of concern because of
their adverse effects on human health and their influence
on photochemical smog processes.1-5 Formaldehyde is a
confirmed animal carcinogen and a suspected human
carcinogen.6 Acetaldehyde and its oxidation products,
such as peroxyacetylnitrate, have been studied for sus-
pected mutagenic and carcinogenic effects.7 Additionally,
both compounds are eye and respiratory irritants. In am-
bient urban environments, formaldehyde and acetalde-
hyde are both emitted directly by traffic and formed in
situ by photochemical processes.8 Inside buildings, sources
of formaldehyde include cigarette smoke, insulating ma-
terials, chipboard or plywood furniture, water-based
paints, fabrics, household cleaning agents, disinfectants,
particle board, and other construction materials.9 Indoor
acetaldehyde concentrations in residences may be related
to emissions from smoking, combustion appliances, cos-
metic products, and some hobby supplies such as photo-
graphic chemicals and special adhesives.10 Since
acetaldehyde is a product of human metabolism and is
present in human expired air, with higher levels observed
in smokers and abstinent alcoholics, indoor residential
concentrations may be related to direct emissions from
humans.11,12 In addition, some indoor activities such as
cooking and baking increase indoor air concentrations of
both formaldehyde and acetaldehyde.13
IMPLICATIONS
The study presented here was a part of the European
Union 4th framework RTD Programme-funded EXPOLIS
study. Objectives of the EXPOLIS study included assess-
ment of European urban population exposures to major
air pollutants and analysis of personal and environmental
determinants of these exposures. Results from this study
confirm that indoor residential air is the most important
determinant of personal exposures to formaldehyde and
acetadehyde in Helsinki.
Exposure is quantified as the amount of agent/sub-
stance available at the exchange boundary of the recep-
tor organism per specified time period.14 It is related
Volume 51 January 2001
Journal of the Air & Waste Management Association 17

Jurvelin et al.
Table 1. Subsample of 15 participants (n = 15) vs. respondents of Helsinki base
directly to the pollutant of interest, to the individual, and
to the time and duration of exposure. Several studies have
shown that personal exposures to many pollutants corre-
late much better with indoor than with outdoor concen-
trations.15,16 These findings can partly be explained by the
high proportion of time that people spend indoors (about
85–95%).17,18
There have been few studies of formaldehyde and ac-
etaldehyde where nonoccupational levels of personal ex-
posure have been directly measured and compared to
microenvironmental concentrations (such as indoor resi-
dential, outdoor, and workplace).19,20 Personal 48-hr ex-
posures to formaldehyde and acetaldehyde of 15 randomly
selected participants in the Helsinki metropolitan area,
Finland, together with microenvironmental concentra-
tions in participants’ residences (indoor and outdoor) and
in workplaces, were measured as a part of a European study
of air pollution exposures, EXPOLIS. This paper introduces
personal and microenvironmental sampling and analysis
techniques for formaldehyde and acetaldehyde together
with personal exposures and microenvironmental con-
centrations measured in Helsinki.
sample.
Study Sample
Respondents (25–55 years)
(n = 15) %
(n = 1881) %
Gender
Men
27
73
44
56
Women
Age
25–34 Years
35–44 Years
45–55 Years
Self Smoking
Yes
27
33
40
32
32
36
27
73
28
72
No
Marital Status
Married
80
7
68
21
10
Not married
Divorced
13
Unemployed or Working at Home
Yes
20
80
16
84
No
Home Type
Single family or attached house 47
33
65
EXPERIMENTAL METHODS
Block of flat
Home Area
≤60 m2
53
Population Sample
27
73
37
62
The target populations of EXPOLIS were European adult
urban inhabitants.21 In Helsinki, a base sample of 2523
adults (25–55 years of age) was randomly selected from
the population census of the Helsinki metropolitan area.
A short screening questionnaire was completed and re-
turned by 1881 participants of this base population
sample. A subsample of 15 participants was drawn at ran-
dom from these 1881 participants for measurement of
formaldehyde and acetaldehyde exposures.
In Table 1, some characteristics of the subsample are
presented and compared to the 1881 respondents of the
Helsinki base sample. The evaluation of the population
sampling bias between the 1881 respondents and the
Helsinki metropolitan area population has been presented
elsewhere.22 The subsample consisted of 11 women and 4
men between 31 and 54 years of age. Two of the partici-
pants were unemployed and four smoked during the
48-hr sampling period. One of the smokers smoked in-
doors in the residence and three participants reported that
smoking occurred in their workplace. One participant
lived in a single-family house, six in attached houses, and
eight in apartment buildings. None of the single-family
or attached houses had an attached garage.
>60 m2
during the summer and autumn of 1997 (May 14–
September 26, 1997). Formaldehyde and acetaldehyde
were sampled in addition to PM2.5, NO2, and volatile or-
ganic compounds (VOCs), which were the core analytes
of the EXPOLIS study. Personal exposures were measured
by personal exposure monitors (PEMs) carried by each par-
ticipant for 48 hr. Microenvironmental monitors (MEMs)
were placed inside and outside of each participant’s resi-
dence and in each participant’s workplace and were pro-
grammed to run for self-reported nonworking hours and
self-reported working hours, respectively. The total num-
ber of outdoor measurements at residences was 13, as there
were no suitable locations for two participants to install
the outdoor MEM. In addition, microenvironmental con-
centrations at workplaces (indoor) were measured for 10
participants, as it was not possible to measure in the work-
place for three participants and two participants were
unemployed. One workplace measurement was carried out
in the residence, as one participant worked at home.
Formaldehyde and acetaldehyde were sampled using
Sep-Pak DNPH-Silica cartridges (Waters). Air was drawn
through the cartridge using the vacuum generated by the
PM2.5 pump. An aldehyde sampling line was connected
to the PM2.5 sampling line by a T-joint, and diffusive flow
Personal and Microenvironmental
Measurements
Personal exposure levels and microenvironmentalconcen-
trations of formaldehyde and acetaldehyde were measured
18 Journal of the Air & Waste Management Association
Volume 51 January 2001

Jurvelin et al.
during nonsampling periods was limited by small-pore
Teflon tubes (350 mm in length, 1.6-mm i.d.) placed in
front of and behind the sampling cartridge. Airflow
through the cartridge was measured before and after each
sampling period with a bubble flow meter (Mini Buck
Calibrator M-1, A.P. Buck Inc.). Sample volumes were cal-
culated using the average of pre- and postsampling flow
rates. In personal exposure measurements, the average
sampling volume was 66.4 L with a standard deviation
(SD) of 14.9 L. In microenvironmental measurements, the
average sampling volume was 122.6 L (SD 46.0 L). The
average sample flow rate was 23.6 mL/min (SD 5.3
mL/min) in personal exposure measurements and 91.6
mL/min (SD 21.4 mL/min) in microenvironmental mea-
surements. To avoid a negative interference from O3, a
copper tube (500 mm in length, 4-mm i.d.) with KI coat-
ing was used as an O3 scrubber for all samples.23
PEMs were packed into aluminum briefcases (5.2 kg
total), which could be carried in the hand, as shoulder bags,
or as backpacks by the participants during their daily ac-
tivities. The modified PEM pump (Buck I.H., A.P. Buck) was
equipped with a volumetric flow control and could be op-
erated for the entire 48-hr sampling period on a single set
of batteries. MEMs were packed into portable sound-
absorbing containers (MDF-board coated with a low-emis-
sion paint). The MEM pump (BGI PQ100, BGI Inc.) could
be operated for up to 36 hr on an internal lead-acid bat-
tery. The pump was equipped with a mass flow control
and timing. In microenvironmental measurements, MEMs
were located in central representative locations at least
1 m away from the wall and 50 cm from the floor/ground
level. Air was sampled outside of the boundary layer of the
PEM case or the MEM container for both personal and
microenvironmental sampling. Both temperature and rela-
tive humidity (Extech 445922, Extech Inc.) were measured
when MEMs were delivered and collected from the resi-
dence or workplace. Sampling data were recorded in the
EXPOLIS database after each measurement.21
0% and ACN was increased to 73%. Finally, ACN was in-
creased to 90% and maintained for 2 min (from min 15
to 20 of each run). Analytical and reference wavelengths
were 360 and 450 ηm, respectively.
Pure 2,4-dinitrophenylhydrazine (DNPH) derivatives
of formaldehyde and acetaldehyde were synthesized
separately for standards by reaction with DNPH. Satu-
rated DNPH solution was prepared in 2 M HCl and the
solution was filtered through a hydrophilic membrane
filter (0.45-µm pore size). Formaldehyde and acetalde-
hyde were added and stirred for 30 min. The formed solid
derivative was filtered and washed 3 times with 2 M HCl
and 3 times with water and dried overnight in an oven
at 60 °C. Subsequently, it was dissolved in hot ethyl al-
cohol and recrystallized, filtered, and dried in the oven.
A series of standard solutions were prepared in ACN. The
percent relative standard deviation (RSD) for 56 stan-
dard solutions was 4.0% for formaldehyde and 4.6% for
acetaldehyde.
Questionnaires and Time-Activity Monitoring
Questionnaires were used in the EXPOLIS study to obtain
information on factors thought to affect personal expo-
sure levels or the quality of indoor air in the participant’s
residence and workplace. A time-microenvironment-
activity diary was used to assess the times that partici-
pants spent in each microenvironment and the activities
performed during the 48-hr measurement period.21
Partial Model of Average Exposure
Data collected in EXPOLIS are used to develop and test
models for predicting personal exposure. A partial model
of average exposure for formaldehyde and acetaldehyde
was used, which consisted of proportionally weighting
the time spent in microenvironments where concentra-
tion measurements were carried out by concentrations in
each respective microenvironment.
E = (CITI + COTO + CWTW)/(TI + TO + TW)
(1)
Sample Analysis
Hydrazone derivatives of formaldehyde and acetaldehyde
were eluted from Sep-Pak DNPH-Silica cartridges with
3-mL acetonitrile (ACN) (HPLC grade). The mass of sol-
vent that was recovered from the silica cartridge in 2 min
was weighed for exact volume determination. An auto-
matic injector injected 15 µL into an HPLC pumping sys-
tem (HP 1050, Hewlett Packard GmbH) with a Hypersil
BDS C18 (3 µm, 100 × 4 mm) column at a flow rate of 1.3
mL/min, coupled with UV detection (Hewlett Packard).
An isocratic run was used for the first 2 min with 60%
water, 35% ACN, and 5% tetrahydrofuran (THF). Subse-
quently, gradient elution was used (from min 2 to 15 of
each run), where the percentage of THF was decreased to
where E is the estimated average personal exposure con-
centration, C is the concentration in measured microen-
vironments (I is indoor residential, O is outdoor residential,
and W is workplace), and T is the time spent in the re-
spective microenvironments.
Quality Assurance/Quality Control
Microenvironmental samples for four participants were
accompanied by field blanks. These consisted of com-
plete formaldehyde and acetaldehyde sampling assem-
blies, which underwent all sample procedures, except
that they were not connected to a sampling pump. De-
termination of formaldehyde and acetaldehyde
Volume 51 January 2001
Journal of the Air & Waste Management Association 19

Jurvelin et al.
sampling precision was based on field duplicate mea-
surements (n = 3) collected in the field along with the
normal sample.
the outdoor residential samples was below limits of de-
tection due to low concentration levels of these com-
pounds in this microenvironment. Comparison with other
studies that used Sep-Pak cartridges indicated similar de-
tection limits and precision, although the number of field
blanks and duplicates in this study were small.3-5,8,11,25,26
RESULTS AND DISCUSSION
Quality Assurance/Quality Control
Aldehyde and PM2.5 samples were drawn simultaneously
using the same pump. Flow resistance of PM2.5 filters
increased with loading of particles during the sampling
periods. Consequently, there was a potential for in-
creased flow through aldehyde sampling cartridges in
microevironmental measurements as a mass flow-con-
trolled pump was used to draw air for both samples using a
T-joint in the sample lines. Thus, it was possible for form-
aldehyde and acetaldehyde concentrations to be somewhat
over-represented toward the end of each sample relative to
the beginning. Measured differences in pre- and
postsampling flow rates for microenvironmental measure-
ments, however, were small, with a mean change of 7.5%
(SD 4.8%) due to the low PM2.5 masses collected. Personal
exposure measurements used a volumetric flow-controlled
pump, which kept the pump speed constant as the particle
load on PM2.5 filters increased. Consequently, flow rate
changes for personal samples were minimal (mean –1.1%,
SD 7.0%) when the PM2.5 filters got loaded during the sam-
pling period. The combined effect of these flow-rate change
differences resulted in less than 10% differences in con-
centrations in side-by-side PEM and MEM VOC sampling
comparisons carried out as a part of the EXPOLIS, and there-
fore did not introduce significant error.
Time Activities of the Sampled Participants
Participants of this study spent, on average, 62% of the
48-hr sampling period at the residence (Table 2), 88% in-
doors, and 4% outdoors. Time spent in traffic and trans-
portation (inside a vehicle or in close proximity to road
traffic) is not included in these percentages. These values
are similar to those found in other studies.17
Concentration Levels
Mean 48-hr personal exposure levels (including smokers)
of formaldehyde and acetaldehyde were 21.4 (7.6–40.3
ppb) and 7.9 ppb (1.4–13.9 ppb), and mean indoor resi-
dential concentrations (including the home where smok-
ing occurred indoors) of formaldehyde and acetaldehyde
were 33.3 and 10.1 ppb, respectively (Table 3). Compari-
son of smokers with nonsmokers is not supported by this
study, as the numbers of smokers (n = 4) and residences
(n = 1) or workplaces (n = 3) where smoking occurred in-
doors were very small, which precluded meaningful com-
parison. Personal exposure levels of active smokers reflect
concentrations of formaldehyde and acetaldehyde in the
air around each study participant and not the dose re-
ceived from actively inhaling smoke directly from a ciga-
rette. Measured doses from directly inhaling cigarette
smoke were not measured or estimated in our study be-
cause there is a wealth of literature already available on
this topic.
In general, personal exposure levels were lower than
indoor residential concentrations. This suggests that con-
centrations of formaldehyde and acetaldehyde in indoor
residential environments were higher than those found
in other microenvironments in which participants spent
significant portions of the day, and that participants spent
only a small amount of time in nonresidential microen-
vironments where concentrations were high (e.g., traffic)
and more time in locations where concentrations were
low (e.g., workplace, outdoors).
Mean contamination levels found in field blanks were
0.80 ppb (0.68-1.03 ppb) for formaldehyde and 0.67 ppb
(0.32-1.04 ppb) for acetaldehyde (using an assumed sam-
pling volume of 100 L). Limits of detection were defined
as 3 times the standard deviation of the field blanks and
were 0.50 ppb for formaldehyde and 1.00 ppb for acetal-
dehyde. One-half of the detection limit was used for data
below the limit of detection in statistical analyses.24
Percentages of samples above the limit of detection
for formaldehyde were 100% (15/15) for personal expo-
sure samples, 100% (15/15) for indoor residential samples,
85% (11/13) for outdoor residential samples, and 100%
(10/10) for workplace samples. Respective percentages for
acetaldehyde were 100% (15/15), 100% (15/15), 62%
(8/13), and 90% (9/10). The mean RSD for microenviron-
mental duplicate pairs was 2.7% (0.1–4.3%) for formalde-
hyde and 1.6% (0.7–3.2%) for acetaldehyde.
Ambient air concentrations measured outside each
participant’s residence were low compared with indoor (in-
door residential and workplace) concentrations and personal
exposure levels. Mean outdoor concentrations of formalde-
hyde and acetaldehyde were 2.6 and 1.5 ppb, respectively.
The ratio of mean indoor to mean outdoor concentrations
was 12.8 for formaldehyde and 6.7 for acetaldehyde, and
individual indoor/outdoor ratios were greater than unity for
almost every measurement pair (Table 4).
The sensitivity of current methods was adequate for
the measurement of personal exposures and microenvi-
ronmental concentrations of formaldehyde and acetal-
dehyde. In this study, percentages of samples above the
limits of detection were greater than 90% for all microen-
vironments except outdoor residential samples. A part of
20 Journal of the Air & Waste Management Association
Volume 51 January 2001

Jurvelin et al.
Table 2. Time activities of the participants (n = 15) during the 48-hr sampling period.
Microenvironment
Residence
In Transit
Not in Transit
Work
% of
Time
Walk or Bike Car or Taxi Bus or Tram
Other
In
Out
In
Out
In
Out
Mean
Min
3.5
0
3.5
0
0.8
0
61.7
24.4
87.3
3.1
0
22.3
0
0.4
0
4.1
0
0.6
0
Max
18.4
20.3
6.3
13.5
53.8
2.9
26.8
4.2
Table 3. The 48-hr personal exposure levels and indoor residential, outdoor residential, and workplace concentrations of formaldehyde and acetaldehyde (in ppb). The analysis of
workplace concentrations does not include the participant who worked at home.
Personal (n = 15)
Residential-In (n = 15)
Residential-Out (n = 13)
Workplace (n = 9)
Formald.
Acetald.
Formald.
Acetald.
Formald.
Acetald.
Formald.
Acetald.
Mean
SDa
50thb
75thc
Min
21.4
11.1
18.0
29.1
7.6
7.9
3.9
33.3
17.9
33.0
47.8
6.5
10.1
5.4
2.6
2.9
1.5
1.6
1.2
1.3
0.5
6.5
12.0
6.1
2.6
1.2
3.3
3.6
0.5
4.0
7.1
9.1
1.5
11.1
12.3
7.3
10.5
1.4
12.0
2.0
3.2
0.3
Max
40.3
13.9
62.3
22.7
10.9
26.4
aStandard deviation; b50th percentile; c75th percentile.
Mean indoor workplace concentrations of formalde-
hyde and acetaldehyde (including workplaces where
smoking occurred indoors) were 12.0 and 2.6 ppb, respec-
tively. Analysis of workplace concentrations does not in-
clude one participant who worked at home. Generally,
concentrations of formaldehyde and acetaldehyde were
lower in workplaces than in residences. This suggests that
there were more indoor sources of formaldehyde and ac-
etaldehyde in residences (e.g., building materials which
emit formaldehyde and acetaldehyde) and/or workplaces
had better ventilation. It is also possible that there were
additional formaldehyde and acetaldehyde sinks at work-
places compared with residences.
from 250 randomly selected residences in Perth, Western
Australia. The mean personal exposure level (17.5 ppb)
was lower than that measured in Helsinki due to lower
indoor residential concentrations in Perth. Mean indoor
residential concentration in Perth (19.7 ppb) was higher
than respective mean personal exposure concentration
and 10 times higher than respective mean outdoor resi-
dential concentration (2.0 ppb).
In another study carried out in New Jersey,11 simulta-
neous indoor and outdoor residential measurements of
aldehydes were made for six suburban houses during the
summer of 1992. In this study, the mean indoor concen-
trations of formaldehyde and acetaldehyde were 54.6 and
3.0 ppb and mean outdoor concentrations were 12.5 and
2.6 ppb, respectively. Mean indoor/outdoor concentration
ratios were 7.20 for formaldehyde and 1.38 for acetalde-
hyde. Reiss et al.26 measured indoor residential and out-
door concentrations of carbonyl compounds in the greater
Boston, MA, area during the winter (n = 4 residences) and
summer (n = 9 residences). During the summer, mean in-
door and outdoor formaldehyde concentrations were 16.1
and 2.6 ppb, and mean indoor and outdoor acetaldehyde
concentrations were 5.1 and 1.1 ppb, respectively.
Indoor residential concentrations of acetaldehyde in
Helsinki were generally higher than indoor concentrations
in New Jersey and Boston. No such difference was observed
Dingle et al.20 reported personal exposures and in-
door and outdoor residential concentrations (all 5-day
average concentrations) of formaldehyde for 80 volunteers
Table 4. Statistics of the I/O ratios of formaldehyde and acetaldehyde in residential
air (n = 13).
Compound
Mean
50tha
75thb
Min
Max
Formaldehyde
Acetaldehyde
44.8
14.2
25.7
10.9
39.6
19.5
1.5
0.8
217.5
43.2
a50th percentile; b75th percentile.
Volume 51 January 2001
Journal of the Air & Waste Management Association 21

Jurvelin et al.
Table 5. Summary of Spearman correlation coefficients between personal expo-
sure (n = 15) levels and indoor residential (n = 15) and outdoor residential (n = 13)
concentrations of formaldehyde and acetaldehyde.
in outdoor concentrations. In addition, mean indoor/out-
door concentration ratios of both formaldehyde and ac-
etaldehyde were higher in Helsinki than in New Jersey. The
higher indoor residential concentrations of acetaldehyde
observed in Helsinki may result from differences in physi-
cal properties of the buildings (e.g., lower air-exchange rates
in Helsinki), building materials, and chemical processes
governing the generation, accumulation, and removal of
this compound in the indoor environments.11
Formaldehyde
Measurement
Personal
Exposure
Residential-
In Conc.
Residential-
Out Conc.
Personal exposure
Residential-in conc.
Residential-out conc.
1.0
0.804a
–0.300
1.0
–0.386
1.0
Correlation between 48-hr Personal Exposure
Levels and Microenvironmental Concentrations
Personal 48-hr exposures to formaldehyde and acetalde-
hyde were correlated with indoor residential concentrations
of these compounds (Table 5). There was no significant
correlation, however, between personal exposure levels and
indoor workplace concentrations (n = 9) for formaldehyde
(rs = 0.150) and acetaldehyde (rs = 0.151) or between per-
sonal exposures and concentrations in ambient air (out-
door residential). Dingle et al.20 reported a correlation (r =
0.780) between personal exposures and indoor residential
concentrations of formaldehyde that was similar to the cur-
rent study. These findings indicate that for formaldehyde
and acetaldehyde, outdoor air concentrations are a poor
proxy of personal exposure levels.
Acetaldehyde
Residential-
In Conc.
Measurement
Personal
Exposure
Residential-
Out Conc.
Personal exposure
Residential-in conc.
Residential-out conc.
1.0
0.819a
–0.154
1.0
–0.393
1.0
Note: The significance level of the correlations are denoted as follows: aProbability <
0.001.
studies on personal exposure to NO2 have reported that
time weighting is of minor importance for estimating per-
sonal NO2 exposures.27,28
Measured 48-hr Personal Exposure
Levels Versus Partial Model of
Average Exposure
It is important to note that the partial model
of average exposure only covered the moni-
tored microenvironments and the time spent
in these environments. It did not cover
nonmonitored microenvironments such as
shops, restaurants, and traffic even if the par-
ticipants could visit these environments dur-
ing their 48-hr sampling period. The model
explained 54% of the variation in formalde-
hyde personal exposures and 59% of the varia-
tion in acetaldehyde personal exposures using
logarithmically transformed data (Figure 1).
Interestingly, measured indoor residential
concentrations predicted measured personal
exposures better than the used model did (for
formaldehyde, R2 = 0.61 and for acetaldehyde,
R2 = 0.78) (Figure 2). Dingle et al.20 also re-
ported that the time-weighted formaldehyde
exposure model did not improve estimation
of personal exposures compared with predic-
Figure 1. Measured 48-hr personal exposure levels vs. partial model of average exposure
(n = 12). The model consisted of proportionally weighting the time spent in the
microenvironments where concentration measurements were carried out by concentrations
in each respective microenvironment. For regression analysis, data were logarithmically
tion using indoor residential concentrations.
These results emphasize the importance of
residential formaldehyde and acetaldehyde
concentrations for personal exposures. Other transformed.
22 Journal of the Air & Waste Management Association
Volume 51 January 2001

Jurvelin et al.
Formaldehyde-to-Acetaldehyde Ratio
Concentration ratios of formaldehyde and ac-
etaldehyde have been used to compare the re-
sults of carbonyl compound measurement
studies in different locations.8,29 The high cor-
relation between formaldehyde and acetalde-
hyde suggests that these two compounds have
similar sources and sinks. In this study, form-
aldehyde and acetaldehyde were correlated in
outdoor air (p < 0.001) (Table 6). In indoor mi-
croenvironments and personal exposures,
there was no correlation between compounds.
Contrary to our study, Reiss et al.26 reported
significant correlation between formaldehyde
and acetaldehyde in indoor residential air.
Combined with higher indoor concentrations
in Helsinki, this indicates there were additional
but separate indoor sources of formaldehyde
and acetaldehyde in residences of Helsinki
compared with those of Boston. It is also pos-
sible that the numbers of sinks of both com-
pounds were lower or that the sinks were
weaker in Helsinki residents.
Figure 2. Measured 48-hr personal exposure levels vs. indoor residential concentrations
(n = 15). For regression analysis, data were logarithmically transformed.
Mean formaldehyde-to-acetaldehyde con-
centration ratios (ppb/ppb) increased from out-
door residential (1.69) to personal exposure
(3.46), indoor residential (4.02), and workplace (5.93).
The mean outdoor formaldehyde-to-acetaldehyde con-
centration ratio in Helsinki is consistent with data from
other urban areas.3,8 The highest mean observed in work-
places resulted from low indoor workplace concentra-
tions of acetaldehyde.
systematically lower than indoor residential concentra-
tions. Outdoor residential concentrations were low com-
pared with indoor residential concentrations and personal
exposure levels. Mean concentrations of both compounds
were lower indoors in workplaces than in residences. Per-
sonal exposure levels of formaldehyde and acetaldehyde
were correlated with indoor residential concentrations,
but not with workplace or outdoor residential concentra-
tions. Indoor residential concentrations alone were bet-
ter estimators of personal exposures than was a
time-weighted exposure model. Concentration levels of
formaldehyde and acetaldehyde were correlated in out-
door residential microenvironments, but not in indoor
microenvironments or personal exposure samples. This
suggests that both compounds have similar sources and
sinks in ambient urban air, but not in indoor air, which
dominates personal exposures.
CONCLUSIONS
Mean 48-hr personal exposure was found to be 21.4 ppb
for formaldehyde and 7.9 ppb for acetaldehyde among
15 participants living in the Helsinki metropolitan area.
For both compounds, personal exposure levels were
Table 6. Summary of concentration ratios and Spearman correlation coefficients
between formaldehyde and acetaldehyde in personal exposure and microenvironmen-
tal concentration samples. The analysis of workplace concentrations does not include
the participant who worked at home.
Formaldehyde/Acetaldehyde (ppb/ppb)
ACKNOWLEDGMENTS
Measurement
Mean
SDa
rsb
This work has been supported by EU Contract No. ENV4-
CT96-0202 (DG 12-DTEE), EU Contract No.
ERBIC20CT96-0061, Academy of Finland Contract No.
36586, NESTE Foundation, and intramural funding by
KTL, the National Public Health Institute of Finland. Spe-
cial thanks go to Dr. Rufus Edwards (Division of Environ-
mental Health, KTL, Kuopio, Finland) for technical editing
of the manuscript.
Personal Exposure (n = 15)
Residential-in (n = 15)
Residential-out (n = 13)
Workplace (n = 9)
3.46
4.02
1.69
5.93
2.59
2.82
0.95
4.09
0.136
0.438
0.844c
0.117
aStandard deviation; Spearman correlation coefficient; The significance level of the
b
c
correlations are denoted as follows: Probability < 0.001.
Volume 51 January 2001
Journal of the Air & Waste Management Association 23

Jurvelin et al.
22. Rotko, T.; Oglesby, L.; Kuenzli, N.; Jantunen, M. J. Expos. Anal. Environ.
Epidemiol. 2000, 10, 355-364.
23. Arnts, R.R.; Tejda, S.B. Environ. Sci. Technol. 1989, 23, 1428-1430.
24. Hornung, R.W.; Reed, L.D. Appl. Occup. Environ. Hyg. 1990, 5, 46-51.
25. Granby, K.; Christensen, C.S.; Lohse, C. Atmos. Environ. 1997, 31,
1403-1415.
26. Reiss, R.; Ryan, P.B.; Tibbetts, S.J.; Koutrakis, P. J. Air & Waste Manage.
Assoc. 1995, 45, 811-822.
27. Clausing, P.; Mak, J.K.; Spengler, J.D.; Letz, R. Environ. Int. 1986, 12,
413-417.
28. Noy, D.; Brunekreef, B.; Boleu, J.S.M.; Houthuus, D.; De Koning, R.
Atmos. Environ. 1990, 24A, 2903-2909.
29. Anderson, L.G.; Lanning, J.A.; Barrell, R.; Miyagishima, J.; Jones, R.H.;
Wolfe, P. Atmos. Environ. 1996, 30, 2113-2123.
REFERENCES
1. Carlier, P.; Hannachi, H.; Mouvier, G. Atmos. Environ. 1986, 20, 2079-
2099.
2. Carter, W.P.L. Atmos. Environ. 1990, 24A, 481-518.
3. Grosjean, D. Environ. Sci. Technol. 1991, 25, 710-715.
4. Grosjean, E.; Grosjean, D.; Fraser, M.P.; Cass, G.R. Environ. Sci. Technol.
1996, 30, 2687-2703.
5. Williams, I.D.; Revitt, D.M.; Hamilton, R.S. Sci. Total Environ. 1996,
189/190, 475-483.
6. Hileman, B. Environ. Sci. Technol. 1984, 18, 216-225.
7. Shepson, P.B.; Kleindienst, T.E.; Edney, E.O.; Nero, C.M.; Cupitt, L.T.;
Claxton, L.D. Environ. Sci. Technol. 1986, 20, 1008-1013.
8. Grosjean, E.; Williams, E.L.; Grosjean, D. J. Air & Waste Manage. Assoc.
1993, 43, 469-474.
9. Humfrey, C.; Shuker, L.; Harrison, P. IEH Assessment on Indoor Air Qual-
ity in Home, Assessment A2; Medical Research Council, Institute for
Environment and Health: Leicester, United Kingdom, 1996.
10. Maroni, M.; Seifert, B.; Lindvall, T. Indoor Air Quality, A Comprehensive
Reference Book; Elsevier Science: Amsterdam, The Netherlands, 1995;
Vol. 3.
11. Zhang, J.; He, Q.; Lioy, P.J. Environ. Sci. Technol. 1994, 28, 146-152.
12. Jones, A.W. Alcohol 1995, 30, 271-285.
13. Vainiotalo, S.; Matveinen, K. Am. Ind. Hyg. Assoc. J. 1993, 54, 376-
382.
14. Glossary of Terms Related to Health, Exposure, and Risk Assessment; EPA/
450/3-88/016; U.S. Environmental Protection Agency, Air Risk Infor-
mation Support Center, Office of Air Quality Planning and Standards:
Research Triangle Park, NC, 1989.
15. Ryan, B.; Spengler, J.D.; Letz, R. Environ. Int. 1986, 12, 394-400.
16. Hosein, R.; Corey, P.; Silverman, F.; Ayiomamitis, A.; Urch, R.; Alexis,
N. Indoor Air 1991, 1, 457-464.
17. Schwab, M.; Colome, S.D.; Spengler, J.D.; Ryan, P.B.; Billick, I.H.
Toxicol. Ind. Health 1990, 6, 517-532.
18. Ott, W. J. Expos. Anal. Environ. Epidemiol. 1995, 5, 449-472.
19. Bracken, M.J.; Leasa, D.J.; Morgan, W.K.C. Can. J. Public Health 1985,
76, 312-316.
20. Dingle, P.; Shuwee, H.; Murray, F. In Proceedings of Indoor Air ‘93;
Saarela, K., Kalliokoski, P., Seppänen, O., Eds.; Gummerus Oy:
Jyvaskyla, Finland, 1993; pp 293-298.
About the Authors
Jouni Jurvelin, M.Sc., and Matti Vartiainen, Ph.D., are re-
searchers and Matti Jantunen, Ph.D., is the director of the
Department of Environmental Hygiene at KTL (National Pub-
lic Health Institute), P.O. Box 95, FIN-70701 Kuopio, Fin-
land. Pertti Pasanen, Ph.D., is a lecturer in environmental
engineering in the Department of Environmental Sciences
at the University of Kuopio, P.O. Box 1627, FIN-70211
Kuopio, Finland.
21. Jantunen, M.J.; Hänninen, O.; Katsouyanni, K.; Knöppel, H.; Kuenzli,
N.; Lebret, E.; Maroni, M.; Saarela, K.; Sram, R.; Zmirou, D. J. Expos.
Anal. Environ. Epidemiol. 1998, 8, 495-518.
24 Journal of the Air & Waste Management Association
Volume 51 January 2001