Indoor air quality in schools

Abstract

In recent years, the use of synthetic materials in building and furnishing, the adoption of new lifestyles, the extensive use of products for environmental cleaning and personal hygiene have contributed to the deterioration of indoor air quality and introduced new sources of risk to humans. Indoor environments include home, workplaces such as offices, public buildings such as hospitals, schools, kindergartens, sports halls, libraries, restaurants and bars, theaters and cinemas and finally cabins of vehicles. Indoor environments in schools have been of particular public concern. According to recent studies, children aged between 3 and 14 spend 90 % of the day indoors both in winter and summer. Moreover, children have greater susceptibility to some environmental pollutants than adults, because they breathe higher volumes of air relative to their body weights, and their tissues and organs are actively growing. In this review, the authors explore the methodological approaches used for the assessment of air quality in schools: monitoring strategies, sampling and analysis techniques and summarizing an overview of main findings from scientific literature concerning the most common pollutants found in school environments.

Full text

1 23
Environmental Chemistry Letters
ISSN 1610-3653
Environ Chem Lett
DOI 10.1007/s10311-014-0470-6
Indoor air quality in schools
Gianluigi de Gennaro, Paolo Rosario
Dambruoso, Annamaria Demarinis
Loiotile, Alessia Di Gilio, Pasquale
Giungato, et al.

1 23
Your article is protected by copyright and
all rights are held exclusively by Springer
International Publishing Switzerland. This e-
offprint is for personal use only and shall not
be self-archived in electronic repositories. If
you wish to self-archive your article, please
use the accepted manuscript version for
posting on your own website. You may
further deposit the accepted manuscript
version in any repository, provided it is only
made publicly available 12 months after
official publication or later and provided
acknowledgement is given to the original
source of publication and a link is inserted
to the published article on Springer's
website. The link must be accompanied by
the following text: "The final publication is
available at link.springer.com”.

REVIEW
Indoor air quality in schools
Gianluigi de Gennaro •Paolo Rosario Dambruoso •Annamaria Demarinis Loiotile •
Alessia Di Gilio •Pasquale Giungato •Maria Tutino •Annalisa Marzocca •
Antonio Mazzone •Jolanda Palmisani •Francesca Porcelli
Received: 13 May 2014 / Accepted: 16 May 2014
ÓSpringer International Publishing Switzerland 2014
Abstract In recent years, the use of synthetic materials in
building and furnishing, the adoption of new lifestyles, the
extensive use of products for environmental cleaning and
personal hygiene have contributed to the deterioration of
indoor air quality and introduced new sources of risk to
humans. Indoor environments include home, workplaces
such as offices, public buildings such as hospitals, schools,
kindergartens, sports halls, libraries, restaurants and bars,
theaters and cinemas and finally cabins of vehicles. Indoor
environments in schools have been of particular public
concern. According to recent studies, children aged
between 3 and 14 spend 90 % of the day indoors both in
winter and summer. Moreover, children have greater sus-
ceptibility to some environmental pollutants than adults,
because they breathe higher volumes of air relative to their
body weights, and their tissues and organs are actively
growing. In this review, the authors explore the methodo-
logical approaches used for the assessment of air quality in
schools: monitoring strategies, sampling and analysis
techniques and summarizing an overview of main findings
from scientific literature concerning the most common
pollutants found in school environments.
Keywords Carbon dioxide (CO
2
)Formaldehyde and
carbonyl compounds Indoor air quality (IAQ) Inorganic
gases Monitoring strategies Ozone (O
3
)Particulate
matter (PM) School environments sources Volatile
organic compounds (VOCs)
Introduction
In recent years, numerous scientific studies highlighted that
citizens spend most of their time in indoor environments,
e.g., home, offices, schools, hospitals, kindergartens, sports
halls, libraries, restaurants, bars, theaters and vehicles.
Citizens are more exposed to indoor pollution than outdoor
G. de Gennaro (&)A. D. Loiotile P. Giungato 
A. Marzocca J. Palmisani F. Porcelli
Chemistry Department, University of Bari Aldo Moro,
Via Orabona 4, 70125 Bari, Italy
e-mail: gianluigi.degennaro@uniba.it;
g.degennaro@arpa.puglia.it
A. D. Loiotile
e-mail: annamaria.demarinis@uniba.it
P. Giungato
e-mail: pasquale.giungato@uniba.it
A. Marzocca
e-mail: annalisa.marzocca@uniba.it
J. Palmisani
e-mail: jolanda.palmisani@uniba.it
F. Porcelli
e-mail: francesca.porcelli@uniba.it
G. de Gennaro P. R. Dambruoso A. Di Gilio M. Tutino
Apulia Regions Environmental Protection Agency
(ARPA Puglia), Corso Trieste 27, 70126 Bari, Italy
e-mail: p.dambruoso@arpa.puglia.it
A. Di Gilio
e-mail: a.digilio@arpa.puglia.it
M. Tutino
e-mail: m.tutino@arpa.puglia.it
A. Mazzone
LEnviroS srl, Spin Off of University of Bari, Via Orabona 4,
70125 Bari, Italy
e-mail: antoniomazzone@lenviros.com
123
Environ Chem Lett
DOI 10.1007/s10311-014-0470-6
Author's personal copy

(Blondeau et al. 2005; Bruno et al. 2008; Pegas et al. 2010).
Indoor air quality has a considerable impact on public
health because indoor exposure may pose harmful health
effects such as respiratory and cardiopulmonary patholo-
gies and asthma, especially for children (Yang et al. 2009;
Sohn et al. 2012). There is a considerable interest in the
assessment of the association between air pollution expo-
sure and health effects in school environments, as shown
by more than 70 epidemiological publications currently
available (e.g., Guo et al. 1999; Venn et al. 2000). Indoor
air pollution is characterized by a large variability in pol-
lutants’ concentration among different indoor environ-
ments and may also vary within a specific environment as a
function of location and time. The extent of these varia-
tions depends on factors such as the emission characteris-
tics of the sources, the occupants’ behavior and the
microclimatic and ventilation conditions (Report EUR
16051 EN 1994; UNI EN ISO 16000-1: 2006). Thus,
indoor air pollution and human exposure are highly
dynamic processes rather than static phenomena.
In this review, the attention will be focused on air
quality in school buildings. Children spend large amount of
time in these environments and are more sensitive subjects
to indoor pollutants (Faustman et al. 2000; Mendell and
Health 2005;WHO2006a,b; Chithra and Shiva Nagendra
2012). Several studies reported that indoor air pollution can
increase the chance of long- and short-term health prob-
lems for students and teachers in terms of comfort, pro-
ductivity and academic performance (Daisey et al. 2003;
Shendell et al. 2004; Dijken et al. 2005; Mendell and
Health 2005; Wargocki et al. 2005; Mi et al. 2006;
Shaughnessy et al. 2006; Croome et al. 2008). The indoor
pollution observed inside school buildings can be traced
back to a variety of causes, such as the use of high emitting
materials for building construction and furnishing, minimal
landscaping with poor drainage, heating, ventilation and air
conditioning units, the lack of preventative maintenance,
crowded conditions (Godwin and Batterman 2007) and
cleaning products that release chemicals into the air (UBA
2008). Each school environment is uniquely characterized,
and thus, each personal exposure is determined by a
combination of the outdoor and indoor pollutant levels
(Stranger et al. 2007,2008). In fact, age and location of
school buildings, pollutants transport from outdoor,
chemical reactions in indoor air and heterogeneous pro-
cesses at the air–solid interfaces are the other factors that
influence the pollutant concentrations (Poupard et al.
2005). In developed countries, many studies were con-
ducted during the past decade in order to assess Air quality
in school environments (Seppanen et al. 1999; Daisey et al.
2003; Bartlett et al. 2004; Shendell et al. 2004; Rama-
chandran et al. 2005; Shaughnessy et al. 2006; Godwin and
Batterman 2007) and concentration of a large number of
indoor air pollutants were measured including Carbon
dioxide (CO
2
), Ozone (O
3
), Nitrogen oxides (NO
x
), Carbon
oxide (CO), Sulfur dioxide (SO
2
) (Lee and Chang1999;
Scheff et al. 2000a,b; Bartlett et al. 2004; Shendell et al.
2004; Blondeau et al. 2005; Ramachandran et al. 2005;
Godwin and Batterman 2007) and Volatile Organic Com-
pounds (VOCs) (Kotzias 2005; Godwin and Batterman
2007; Pegas et al. 2010,2012) and Particulate Matter (PM)
(Koutrakis et al. 1992; Ozkaynak et al. 1996; Daisey et al.
2003). The aim of the present review was to describe the
methodological approaches used for the assessment of air
quality in schools, according to the main characteristics of
school environments. Chemical pollutants and their sources
and the monitoring strategies and an overview of the main
scientific findings are discussed. This article is an abridged
version of the chapter by Dambruoso et al. (2013) pub-
lished in the book series Environmental Chemistry for a
Sustainable Word (http://www.springer.com/series/11480).
Indoor environments and pollutants
The wide range of school building designs leads to large
variations in indoor pollutants levels and hence personal
exposure (Ashmore and Dimitroulopoulou 2009). Children
spend their school hours in different environments: class-
rooms, laboratories where available, playgrounds and other
locations within the school. As a result, individual expo-
sure changes related according to the variation in pollutants
levels inside the several school locations (Mejı
´a et al.
2011).
Pollutants emission can occur in many school settings
where different activities take place. Surely the most
important ones with respect to the time spent by children
are the classrooms (Lee and Chang 2000; Hulin et al. 2011;
Bertoni et al. 2002; Blondeau et al. 2005; Mi et al. 2006;
Ekmekcioglu and Keskin 2007; Fromme et al. 2007;
Godwin and Batterman 2007; Diapouli et al. 2008; Wei-
chenthal et al. 2008; Yang et al. 2009; Sofuoglu et al. 2010;
Wu et al. 2010; Goyal and Khare 2011; Gul et al. 2011;
Mejı
´a et al. 2011; Mullen et al. 2011; Park et al. 2011;
Smedje et al. 2011; Szoboszlai et al. 2011; Sohn et al.
2012; Zhang and Zhu 2012); the gyms (Godwin and Bat-
terman 2007; Branis et al. 2009; Branis and Safra
´nek 2011;
Hochstetler et al. 2011; Szoboszlai et al. 2011); the science
labs (often without fume hoods) (Godwin and Batterman
2007; Yang et al. 2009; Jo and Kim 2010; Goyal and Khare
2011; Park et al. 2011; Szoboszlai et al. 2011); the com-
puter rooms (Yang et al. 2009; Wu et al. 2010; Szoboszlai
et al. 2011; Sohn et al. 2012); and the dining halls (Gul
et al. 2011). In addition, the exposure that may occur in
other school environments such as the arts and crafts labs
(Blondeau et al. 2005; Godwin and Batterman 2007); the
Environ Chem Lett
123
Author's personal copy

office rooms (Godwin and Batterman 2007; Goyal and
Khare 2011; Zhang and Zhu 2012), the kitchen (MacIntosh
et al. 2012); the cafeterias (Godwin and Batterman 2007;
Hochstetler et al. 2011; Zhang and Zhu 2012); other mis-
cellaneous use rooms (e.g., music room, library); the
swimming pools or stairwells should be taken into account,
as demonstrated by numerous scientific papers (Godwin
and Batterman 2007; Goyal and Khare 2011; Gul et al.
2011; Zhang and Zhu 2012, Sohn et al. 2012).
In order to give an as complete as possible assessment of
air quality in schools, many authors have considered in
their experimental activities several aspects that may affect
the air quality and so the levels of people exposure
(Stranger et al. 2008; Pegas et al. 2012). Among these, the
most relevant ones appear on the school sites such as
industrial (Scheepers et al. 2010; Tran et al. 2012), rural
(Blondeau et al. 2005; Fromme et al. 2007; Hulin et al.
2011; Tran et al. 2012; Zhang and Zhu 2012), traffic
(Blondeau et al. 2005; Hochstetler et al. 2011; Raysoni
et al. 2011; Szoboszlai et al. 2011; Chithra and Shiva
Nagendra 2012), suburban (Branis and Safra
´nek 2011),
urban (Fromme et al. 2007; Hulin et al. 2011; Mullen et al.
2011; Tran et al. 2012; Zhang and Zhu 2012) or back-
ground site because of the proximity of outdoor relevant
sources (Janssen et al. 1997,2001; Green et al. 2004;Wu
and Batterman 2006; Van Roosbroeck et al. 2007; Appat-
ova et al. 2008; Branis and Safra
´nek 2011; Hochstetler
et al. 2011; Mejı
´a et al. 2011; De Giuli et al. 2012); the age
of the buildings (Godwin and Batterman 2007; Ashmore
and Dimitroulopoulou 2009; Yang et al. 2009; Hochstetler
et al. 2011; Mullen et al. 2011; Zhang and Zhu 2012)in
respect of the type of heating systems (MacIntosh et al.
2012; Park et al. 2011; De Giuli et al. 2012; Corgnati et al.
2007); the quality of the used materials, the capacity to
accumulate or disperse pollutants; the room design (floor
area and room volume) and the level of occupancy (Daisey
et al. 2003; Godwin and Batterman 2007; Theodosiou and
Ordoumpozanis 2008; Weichenthal et al. 2008; Mumovic
et al. 2009; Mejı
´a et al. 2011; Goyal and Khare 2011;
Mullen et al. 2011; Chithra and Shiva Nagendra 2012),
measured by indoor CO
2
levels used as a surrogate of the
rate of outside supply air per occupant (Daisey et al. 2003);
the type and quality of ventilation in terms of number of
doors and windows or the presence of natural or mechan-
ical ventilation systems (Ashmore and Dimitroulopoulou
2009; Goyal and Khare 2011; Mullen et al. 2011, Mejı
´a
et al. 2011, Grimsrud et al. 2006; Lee and Chang 2000;
Mumovic et al. 2009;Wa
˚hlinder et al. 1997; Theodosiou
and Ordoumpozanis 2008; Blondeau et al. 2005), very
important for the removal of pollutants (Sohn et al. 2012;
UBA 2008; Yang et al. 2009).
Many authors emphasized also the decisive role played
by the micrometeorological parameters such as mean
temperature and relative air humidity (Godwin and Bat-
terman 2007, Park et al. 2011; Smedje et al. 2011; Wei-
chenthal et al. 2008; Zhang and Zhu 2012; Fraga et al.
2008; Yang et al. 2009; De Giuli et al. 2012), fundamental
in the emissive process of indoor pollutants, by the choice
of materials of board, desks, chairs, floor, because of their
different emission capacity (Pegas et al. 2010; Yang et al.
2009; Goyal and Khare 2011; Chithra and Shiva Nagendra
2012) and by the activities carried out by the occupants like
the use of cleaning products or collage and painting
activities (Chithra and Shiva Nagendra 2012).
The most common pollutants found in schools and
childcare facilities are the following: PM, VOCs, Formal-
dehyde and Carbonyl compounds, other Inorganic Gases:
NO
x
, CO, SO
2
,CO
2
and O
3
, deeply described in following
paragraphs. Their sources can be classified as: continuous
(with a uniform or irregular pattern) and intermittent
sources (with a periodic or variable pattern) respect to the
duration of their emission activity (UNI EN ISO
16000-1:2006).
Particulate matter
Among the indoor air pollutants, nowadays there is a
growing interest in PM. The aerosol exposure via the
inhalation route represents a major potential source of
hazard for human health, depending on the duration of
exposure and concentrations, size and chemical composi-
tion of airborne particles (Abdel-Salam 2006). In several
papers, in fact, the exposure to high PM10 concentrations
has been associated to increased risk of death for cardio-
vascular or respiratory causes (Englert 2004; Zanobetti and
Schwartz 2005; Forbes et al. 2009; Pope et al. 2009). These
effects may be largely caused also by finer particles that, as
a consequence of their greater surface area, could be an
effective media to transport different kinds of pollutants
(PAHs, heavy metals, asbestos, etc.) deeply into the lung
(Nadadur et al. 2007; Sager and Castranova 2009; Reich
et al. 2009). In particular, the exposure to these finer par-
ticles can cause short- and long-term effects such as
increased respiratory symptoms, decreased lung function,
alterations in tissue and structure lung, in respiratory tract
and premature death (Prieditis and Adamson 2002; Damek-
Poprawa and Sawicka-Kapusta 2003; Wahab and Basma
2004; Huang and Ghio 2006; Hong et al. 2007; Wild et al.
2009; Daresta et al. 2010; Liuzzi et al. 2011).
Although the school environment normally lacks typical
indoor PM sources such as smoking and cooking, many
children are present in a limited space over a period of
several hours. The use of cleaning products and floor polish
can also temporarily affect the air quality determining an
increase in chemical pollutants in school environments. On
Environ Chem Lett
123
Author's personal copy

the other hand, the floor surface type and level of cleaning
are important factors in maintaining low dust levels. The
presence of PM can be related to: (1) insufficient ventila-
tion in schools (especially in winter), (2) infrequently and
unthoroughly cleaned indoor surfaces, (3) a large number
of pupils in relation to room area and volume, (4) low class
level related to floor numbers of school buildings and (5)
resuspension of particles from room surfaces (Sexton and
Ryan 1988), which is related to physical activity of the
pupils. Moreover, numerous studies showed that gas-phase
reactions between O
3
and terpenes (for example used in
cleaning products) can contribute significantly to the
growth of indoor secondary organic aerosols (Weschler and
Shields 1999; Long et al. 2000; Wainman et al. 2000;Li
et al. 2002; Fan et al. 2003; Sarwar et al. 2003).
Recent studies report levels, behaviors and chemical
composition of PM in different indoor environment (e.g.,
Chao and Wong 2002; Gemenetzis et al. 2006; Martuz-
evicius et al. 2008; Olson et al. 2008; Smolı
´k et al. 2008
Lai et al. 2010; Saraga et al. 2010; Zhu et al. 2010; Huang
et al. 2012) and, in particular, in elementary schools
(Fromme et al. 2008; Almeida et al. 2011; Oeder et al.
2012; Pegas et al. 2012; Smolı
´k et al. 2008).
Chithra and Shiva Nagendra (2012) monitored the
PM10, PM2.5 and PM1 concentrations by means of an
environmental dust monitor in order to study the relation-
ship between outdoor and indoor air quality in eight French
schools. The indoor–outdoor (I/O) ratios of PM were higher
than two for coarse fraction and minor than one for finer
fraction. The high I/O value of PM10 concentration and its
behavior indicated significant contribution from the activi-
ties of occupants inside classroom and thus from dust
resuspension. On the contrary, the lower I/O values for PM1
and CO suggested that no indoor source of finer particles
were in classrooms and confirmed their intrusion from the
nearby road and due to vehicular emissions (Fig. 1). This
evidence was confirmed by a strong seasonal variability of
finer PM fraction. Moreover, investigating the influence of
classroom occupancy, the authors found that higher par-
ticulate matter concentrations were detected for classroom
during the periods when the classroom was occupied.
In same way Yang et al. (2009), evaluating indoor air
quality inside three different school environments in Korea
found that the mean I/O PM10 ratios (gravimetric mea-
surements) were higher in the classrooms than in labora-
tories and computers rooms, respectively. In addition,
Diapouli et al. (2008) showed higher I/O ratio for PM10
and PM2.5 inside gymnasium, where intense activity took
place, smoking office and classrooms and the I/O ratio
smaller than one for ultrafine particles (UFP) in all inves-
tigated indoor environments (Fig. 2). These evidences
confirmed that the most important contribution to PM
concentrations in school classroom is the resuspension of
particles due to pupil’s activity.
Fig. 1 Weekly variations in
indoor–outdoor aPM10,
bPM2.5, cPM1 and dCO
concentrations inside classroom
(Chithra and Shiva Nagendra
2012)
Environ Chem Lett
123
Author's personal copy

The presence of carpets in schools building also con-
tributed to poor indoor air quality. Stranger et al. (2007), in
a study regarding Belgium schools, found a significant
difference between I/O ratios calculated for the classrooms
with and without the presence of carpets, and in particular,
the authors reported a mean I/O ratio equal to 2.63 in the
classrooms where carpets were present and mean I/O ratio
equal to 1.03 in the classroom where tiles or linoleum floor
coverage were present.
The more recent study conducted by the same authors in
2008 (Stranger et al. 2008) focused the attention on the
chemical composition of PM collected in 27 primary
schools in the urban and suburban areas of Antwerp
(Belgium). The authors showed the elemental composition
of indoor particulate matter (PM2.5) collected in classroom
and analyzed by the energy dispersive X-ray fluorescence
(ED-XRF) was different than that evaluated in outdoor air.
In particular, they found that the elements such traffic
markers (V, Pb, Cr), S and Fe were the highest contribu-
tions to local outdoor PM, while high contributions to
indoor PM in schools were determined by markers of
crustal resuspension (Si, Ti, Al), Ca and Cl. The higher I/O
ratios were determined for Cl, Ca and crustal species.
Chloride could derive by detergents used for cleaning
activities inside the classroom, while Ca concentrations
could probably be determined by the chalk (mainly CaSO
4
)
used on the blackboards and/or the gypsum walls and
plasters used as construction materials. Finally, crustal
species were probably due to resuspension of dust because
of room occupation. Fromme et al. (2008) also reported the
elemental composition of PM collected by gravimetric
sampling system at two classrooms in Munich. The scan-
ning electron microscopy and the energy dispersive
microanalysis (EDX) on PM filters showed that the indoor
PM consisted mainly of earth crustal materials, detritions
of the building materials and chalk (CaSO
4
). These find-
ings suggested that increase of PM10 concentrations in
classrooms were due to a physical activity of the pupils and
to resuspension of mainly indoor coarse particles, and thus,
indoor-generated PM was less toxic than PM in outdoor air.
The measurements of the microclimatic parameters
(ventilation, temperature and air humidity), which can
influence directly or indirectly the indoor pollutant levels,
result very important in the assessment of air quality in the
school. Fromme et al. (2007) found that PM2.5 indoor
concentrations, gravimetrically measured in several
schools in Munich, increased by 1.7 lg/m
3
per 10 %
increase in humidity and by 0.5 lg/m
3
per increase in CO
2
indoor concentration by 100 ppm. The higher PM con-
centrations in winter and their correlation with CO
2
con-
centrations suggested that inadequate ventilation plays a
major role in the establishment of poor indoor air quality.
In addition, high PM10 concentration measured in low-
level classes and in rooms with high number of pupils
suggested that the physical activity of pupils contribute to a
constant process of resuspension of sedimented particles
(Lee and Chang 1999,2000; Blondeau et al. 2005). Fur-
thermore, Sohn et al. (2012) evaluated the influence of
mechanical ventilation systems on indoor air quality in
school buildings in Korea. The results showed remarkable
difference in indoor air pollutants’ level according to the
operation of mechanical ventilation system and in partic-
ular showed that the ventilation systems decreased the
levels of indoor pollutants in the all selected classrooms.
Therefore, use of mechanical ventilation system can play
key roles in improving the air quality within schools.
Volatile organic compounds
Volatile organic compounds are widely present in school
environments as they are emitted from multiple both internal
and outdoor sources. Among the VOC, the high priority
pollutants that are regulated in indoor environments and that
significantly affect children health are Benzene, Naphtha-
lene, Formaldehyde, Toluene, Xylenes, Styrene, Limonene,
Alpha-pinene and Dichloromethane. Benzene, Toluene,
Xylenes and Styrene can be emitted from solvent-based
paints and consumer products, such as collage and painting
materials, used in the art and craft rooms, from Poly Vinyl
Chloride flooring and adhesive used for gyms covering and
from printed materials (Kotzias 2005). Dichloromethane is
found in adhesives, spray paints, while the presence of
Limonene and Alpha-pinene is more related to the emission
from cleaning products (aerosol and liquid) (Priscilla et al.
2010). Polymeric materials that are used for construction,
Fig. 2 Mean indoor/outdoor ratio of PM10, PM2.5 and UFPs in a
rural area (RU), two blocks away from a major highway (HI), a
residential area (RE), a heavy-trafficked neighborhood in the center of
Athens (UR), a residential area close to a major motorway (MO), a
densely populated area close to a major motorway (HP) and at the
harbor of Athens (HA) (Diapouli et al. 2008)
Environ Chem Lett
123
Author's personal copy

decoration and furnishing of schools are high VOC emitters
due to their composition and large surface areas. Moreover,
wood-based products used for construction of writing desks
and cabinets are important sources of these pollutants in
these environments. Some VOC are associated with a variety
of serious health effects (Shendell et al. 2004) and symptoms
such as asthma and allergic reactions (Sofuoglu et al. 2011).
Moreover, several studies reported a strong association
between mucous membrane irritation, central nervous sys-
tem symptoms and total exposure to VOC; these symptoms
are similar to those that are frequently attributed as a cause of
sick building syndrome (Mølhave et al. 1986; Hodgson et al.
1991). In case of extreme concentrations, some VOC may
result in impaired neurobehavioral function (Burton 1997).
Exposure to high concentrations of several VOC commonly
found in indoor air is associated with cancers in laboratory
animals (Jones 1999). A preliminary screening monitoring
of the sum of the VOC in a school environment can be
conducted by direct measurements with automatic instru-
ments as flame ionization detector (FID) or photo ionization
detector (Hodgson 1995; Pegas et al. 2010). Short-term or
long-term measurement methods allow obtaining informa-
tion about the single pollutants present in the investigated
indoor environment (UNI EN ISO 16000-5: 2007). Short-
term measurements were conducted by active sampling on
stainless steel tube packed with specific adsorbent beds using
low-flow sample pumps (UNI EN ISO 16017-1: 2007; Fraga
et al. 2008; Jo and Kim 2010; Pegas et al. 2010; Scheepers
et al. 2010; ISO 16000-6: 2000). Diffusive sampling is the
recommended method to perform long-term measurements
(usually from few days to several days or weeks) (UNI EN
ISO 16017-2: 2007; Bruno et al. 2005; Angiuli et al. 2003;
Pennequin-Cardinal et al. 2005). VOCs collected onto
adsorbent cartridges were thermally or chemically desorbed
and analyzed by gas chromatography coupled to a flame
ionization detector or to a mass spectrometer (Bruno et al.
2005; Angiuli et al. 2003; Pennequin-Cardinal et al. 2005).
Stainless steel canisters were also used to collect VOC in
indoor environments (Meininghaus et al. 2003; Guo et al.
2004).
Volatile organic compounds monitoring campaigns
conducted in different school environments of several cit-
ies (Michigan, Catania, Athens, Arnhem and Nijmegen,
Brussels, Milan, Thessaloniki, Nicosia) highlighted that
indoor sources, micrometeorological parameters and
building conditions might have negative effects on indoor
air quality (Kotzias 2005; Godwin and Batterman 2007;
Pegas et al. 2010,2012). Moreover, it was found that
increasing ventilation rates and using low-emission mate-
rials improve indoor air quality (Pegas et al. 2010). Godwin
and Batterman 2007, monitoring VOC concentrations over
one workweek in 64 elementary and middle school class-
rooms in Michigan, found that most VOC had low
concentrations (mean of individual species \4.5 lg/m
3
)
also if they were higher than outdoor air concentrations
(mean of individual species \0.51 lg/m
3
). For example,
benzene and toluene concentrations in indoor air were 0.09
and 2.81 lg/m
3
, respectively, while their outdoor concen-
trations were 0.06 and 0.52 lg/m
3
, respectively; the total
concentration of chlorinated compounds was 0.24 lg/m
3
in
indoor air and \0.07 lg/m
3
in outdoor air. These findings
suggested that none of the sampled rooms were contami-
nated and that no building-wide relevant contamination
sources were present. Otherwise, higher indoor levels of
many VOC were registered in two studies involving 14
elementary schools in Lisbon, Portugal (Pegas et al. 2010,
2012). Almost all identified VOC (up to 40 compounds)
showed I/O ratios higher than one. The same results were
found by Kotzias (2005) in schools and kindergartens of
several cities in Southern and Central Europe: the sum of
indoor concentrations ranged from a few micrograms (ca.
8) to 281 lg/m
3
, while outdoor levels ranged from 7 to
153 lg/m
3
. VOC concentrations two to four times higher
than the outdoor concentrations were detected in kinder-
gartens and schools of Arnhem and Nijmegen and in Izmir
(Turkey) (Shendell et al. 2004; Sofuoglu et al. 2011;
Stranger et al. 2008). Among monitored VOC, benzene,
toluene, ethylbenzene and xylenes were most abundant
compounds with I/O ratios exceeding unity.
A huge increase in indoor VOC concentrations was also
observed when art works or science activities were
undertaken concurrently or just prior to the measurements
(Shendell et al. 2004; Godwin and Batterman 2007; Pegas
et al. 2010). In particular, Pegas et al. (2010) found that
there was an increase in VOC concentrations reaching
13 ppm, when glue and paints were used in pupil’s art
class.
Formaldehyde and carbonyl compounds
The most relevant carbonyl compounds detected in indoor
environments are Formaldehyde, Acetaldehyde, Acetone,
Benzaldehyde, Butyraldehyde, Capronaldehyde, 2,5-
Dimethylbenzaldehyde, Isovaleraldehyde, Propionalde-
hyde, m-Tolualdehyde, o-Tolualdehyde, p-Tolualdehyde
and Valeraldehyde. As a result of the several industrial uses
in the manufacture of sheet and insulation materials, paints,
cleaning agents and cosmetics, the carbonyl compounds can
usually be detected in school environments. Wood-based
materials made for indoor use are the following ones: (1)
Particleboard (PB) used as sub-flooring and shelving and in
cabinetry and furniture; (2) hardwood plywood paneling
used for decorative wall covering and used in cabinets and
furniture; (3) medium density fiberboard (MDF) used for
drawer fronts, cabinets and furniture tops. Therefore, articles
Environ Chem Lett
123
Author's personal copy

produced from wood-based materials such as furniture,
doors and paneling are still the most important sources of
these compounds in schools. Formaldehyde (HCHO) is the
most abundant airborne indoor carbonyl and represents an
important constituent of adhesives in the sheet material
industry (Urea–Formaldehyde resins, Phenol–Formalde-
hyde resins, Melamine–Formaldehyde resins and Mela-
mine–Urea–Formaldehyde resins). MDF material contains a
high resin-to-wood ratio and is generally recognized as being
the highest formaldehyde-emitting pressed wood product.
Several studies showed that indoor HCHO concentrations in
schools constructed within 1 year were significantly higher,
indicating that school buildings are characterized by several
indoor HCHO sources such as furnishings made of PB and
MDF. Several carbonyls, such as Formaldehyde, Acetalde-
hyde and Propionaldehyde, are included in the list of air
toxics in the Clean Air Act Amendments of 1990 (USEPA
1991). More specifically, HCHO is defined as a human
carcinogen on the basis of a sufficient evidence of carcino-
genicity from studies in animals and humans and of sup-
porting data on mechanisms of carcinogenesis. In recent
years, scientific findings led an increasing interest in HCHO
detection inside school buildings due to the high risk of
children exposure (WHO 2010; NIOSH/IPCS 2004; IARC
2012). California Office of Environmental Health Hazard
Assessment (OEHHA) set an 8-h chronic and acute inhala-
tion reference exposure level (REL) for HCHO equal to 9, 9
and 55 lg/m
3
, respectively (OEHHA 2008). Acetaldehyde,
an abundant carbonyl in indoor air, has been classified as
probable human carcinogen by USEPA (2003). Acrolein is a
severe lung irritant that, in condition of high acute exposure,
can induce oxidative stress and delayed-onset lung injury,
including asthma, congestion and decreased pulmonary
function. Because of concerns about adverse human health
effects posed by Acrolein, OEHHA set an 8-h chronic and
acute inhalation REL equal to 0.70, 0.35 and 2.5 lg/m
3
,
respectively (OEHHA 2008).
Scientific papers published during the last 10 years
reported experimental results obtained from investigation of
HCHO and other carbonyl compounds in school buildings
(Lee and Chang 2000; Righi et al. 2002; Kotzias 2005;
Mentese and Gullu 2006; Vaizoglu et al. 2003; Hanoune
et al. 2006; Yang et al. 2009; Sofuoglu et al. 2011; Yamashita
et al. 2012; Pegas et al. 2011a,b; Barro et al. 2009). The
measurement of HCHO and other carbonyl compounds was
performed according to the requirements of existing inter-
national standard (ISO 16000-3: 2011). The method is
suitable for determination of these compounds in the
approximate concentration range from 1 lg/m
3
to 1 mg/m
3
and involves drawing air through a cartridge containing
silica gel coated with 2,4-dinitrophenylhydrazine (DNPH)
reagent. The principle of the method is based on the specific
reaction of the carbonyl group with DNPH in the presence of
an acid, to form stable 2,4-dinitrophenylhydrazones. The
DNPH derivatives are analyzed with High performance
liquid chromatography and Ultraviolet (UV) absorption
detector operating at 360 nm (Lee and Chang 2000; Daisey
et al. 2003; Meininghaus et al. 2003; Yang et al. 2009; Pegas
et al. 2010; Park et al. 2011; Sohn et al. 2012).
Pegas et al. (2011a) measured indoor and outdoor con-
centrations of HCHO and other carbonyls in 14 elementary
schools in Lisbon, Portugal. In all the investigated envi-
ronments, indoor aldehydes’ levels were higher than those
observed outdoors, especially for HCHO. Pegas et al.
(2011b) carried out a further measuring campaign in school
buildings in order to evaluate seasonal variation in indoor
and outdoor levels. Most of the assessed carbonyls occur-
red at I/O ratios above unity in all the seasons, and this
evidence showed the influence of indoor sources and
building conditions on indoor air quality. However, it was
observed that carbonyls’ levels were higher during the
warm months.
Yang et al. (2009) characterized HCHO concentrations
within 55 school buildings in Korea, selected on the basis
of the year of construction, in order to relate indoor levels
to the age of school buildings. HCHO levels were mea-
sured inside three different school building environments:
classrooms, laboratories and computer rooms. Experimen-
tal results showed that mean HCHO concentrations inside
classrooms and computer rooms exceeded the acute REL
established by OEHHA. Moreover, HCHO concentrations
inside schools constructed within 1 year were significantly
higher than the Korean Indoor Air Standard, suggesting
that renovated schools have important indoor HCHO
sources, such as furnishings principally made of PB and
MDF. Therefore, in order to improve air quality within
schools, especially within renovated schools, the authors
suggest the implementation of increased ventilation rates
by means of mechanical systems and the use of low-
emitting materials.
Kotzias (2005) reported the experimental results deriv-
ing from measuring campaigns performed in several cities
in Southern and Central Europe in the frame of the AIR-
MEX project (Indoor Air Monitoring and Exposure
Assessment Study). This study highlighted that HCHO and
carbonyls’ concentrations (Acetaldehyde, Propanal and
Hexanal) inside the buildings/kindergartens were up to 7–8
times higher than outdoor, confirming that strong HCHO
indoor sources exist.
Lee and Chang (2000) showed the results of a study
carried out to characterize HCHO levels inside selected
classrooms in Hong Kong in order to compare the mea-
sured concentrations with the established standards and to
suggest policy interventions to improve air quality. HCHO
concentrations (ranging from undetectable to 27 lg/m
3
)
were substantially lower than Honk Kong Indoor Air
Environ Chem Lett
123
Author's personal copy

Quality standard, indicating that there were no apparent
HCHO indoor sources and that classroom furnishing did
not add a remarkable contribution.
Sofuoglu et al. (2011) reported HCHO levels measured
in primary school classrooms and kindergartens in Turkey.
Experimental data revealed that HCHO was one of the
most abundant indoor pollutants and that concentrations
were related to both spatial and seasonal variability. Sim-
ilar HCHO levels between urban and suburban schools, but
different HCHO levels between two urban schools can be
explained by the relative strength of the indoor HCHO
sources compared with the outdoor ones. The HCHO
concentrations measured in classrooms were in the litera-
ture range (10–400 lg/m
3
) although they resulted high if
compared with data related to schools in Sweden (Smedje
et al. 1997a,1997b) China (Lee et al. 2004) and Australia
(Zhang et al. 2006). Furthermore, HCHO levels in class-
rooms were lower than the concentrations measured in
homes and offices (Mentese and Gullu 2006; Vaizoglu
et al. 2003) but similar to those in libraries (Righi et al.
2002; Hanoune et al. 2006). Regarding kindergartens,
HCHO levels were higher than those measured in class-
rooms and difference in urban and suburban concentrations
was not significant. It can be asserted that there were
consistent sources of HCHO inside kindergartens because
neither seasonal nor spatial differences were significant.
The overall average of the concentrations measured in this
study (85 lg/m
3
) was clearly higher than the Dutch kin-
dergartens (from ca. 6 to 11 lg/m
3
) (Kotzias 2005) and in
the range of the Danish and Korean kindergartens (Yang
et al. 2009).
N Gases, carbon oxide and sulfur dioxide
Inorganic gases commonly found in school indoor air are
CO, SO
2
and NO
2
. Sometimes, high H
2
S and NH
3
con-
centrations are determined inside school buildings near
industrial plants such as water treatment plants, waste
treatment, desulfurization plants.
Nitrogen oxides (NO
x
sum both nitrogen monoxide
(NO) and dioxide (NO
2
)) enter in indoor air mainly from
outside, arising from the vehicular traffic, but several
studies showed that the most important factors in increased
exposures to NOx, over that the position of school build-
ings in the city center, where the use of gas appliances for
heating is more (Oie et al. 1993; Alm 1999; Coward et al.
2001; Dimitroulopoulou et al. 2005; WHO 2006a,b). In
particular, long-term exposure to high NO
2
concentrations
promotes the onset of diseases of the respiratory tracts:
epidemiological studies suggested that NO
2
represents a
modest risk factor for respiratory illnesses compared with
the use of electric stoves (Basu and Samet 1999).
Suitable methods for measuring NO
x
in indoor envi-
ronments can be divided into short-term measurement
methods and long-term measurement methods UNI EN
ISO 16000-15: 2008. Short-term measurements can be
performed by continuous analytical monitoring instrument
and by manual methods. The continuous monitoring
instruments are based on principle of Chemiluminescence
and are characterized by high time resolution (10–20 s). By
the manual methods, instead, NO
2
is enriched actively onto
a sorbent medium by means of suction pumps, and the
concentrations obtained by these methods are average
concentrations for the duration of sampling. Long-term
measurements are generally carried out using diffusive
sampler (manual methods) since the noise produced by
continuous analytical monitoring instrument could dis-
courage their use inside confined environments (Lee and
Chang 1999,2000; Blondeau et al. 2005; Poupard et al.
2005; Pegas et al. 2010,2012; Gul et al. 2011; Raysoni
et al. 2011; Sohn et al. 2012; Stranger et al. 2008).
Nitrogen oxides determination in French schools
(Blondeau et al. 2005; Poupard et al. 2005) showed that
vehicular exhaust emission from nearby traffic was the
most important contribute to indoor concentrations. In fact,
I/O ratios of calculated NO
2
varied in a narrow range from
0.88 to 1 as shown by the positive correlation between
indoor and outdoor NO
2
concentrations, since indoor
concentrations reflected the outdoor ones despite varying
of building air-tightness. On the contrary, I/O of NO lied in
a wider range (0.5 \I/O \1), and there was no apparent
correlation with the airtightness of the buildings. The
authors suggested that this evidence was probably related
to differences in the contribution of indoor homogeneous
and heterogeneous reactions that NO undergoes. Similar
considerations were elaborated by Stranger et al. (2008)in
Belgium, by Pegas et al. (2012) in Lisbon and by Lee and
Chang (2000) in Hong Kong.
Gul et al. (2011), confirming the results reported in
previous study, showed that I/O ratios for NO
2
at high
schools located in Eskisehir (Turkey) were [1 in dining
hall or teacher’s room where cooking and smoking activ-
ities took place (1.8 \I/O \3). Moreover, Sohn et al.
(2012) studied the relationship between NO
2
concentra-
tions with indoor ventilation rate and showed that a direct
correlation existed.
CO is a vehicular pollutant; therefore, vehicle exhaust
from roads and parking areas nearby school buildings
represents the most important contributor to CO indoor
exposure. CO levels are generally very low inside schools
since the emissive indoor sources influencing long-term
CO levels can be gas cooking, unflued heaters and smoking
(Alm et al. 1994; Coward et al. 2001). Exposure to high CO
concentrations can cause acute intoxication since this
compound combined with the hemoglobin of human blood
Environ Chem Lett
123
Author's personal copy

produces carboxy-hemoglobin and therefore disrupts the
transfer of oxygen to human tissues. Various symptoms of
neuropsychological impairment were associated with acute
low-level exposure of CO concentration (Raub et al. 2000).
Epidemiological studies reported increased relative risks of
daily mortality and morbidity of the population by
0.9–4.7 % in prevailing urban air (Touloumi et al. 1994;
Burnett et al. 1997,1998).
Both indoor and outdoor measurements of carbon oxides
(CO and CO
2
) were conducted using a non-dispersive
infrared analyzers (NDIR) (Lee and Chang 1999; Chal-
oulakoua and Mavroidisb 2002; Yang et al. 2009; Pegas
et al. 2010,2012; Park et al. 2011; Smedje et al. 2011;
Sohn et al. 2012). Continuous measurements of CO
2
and
CO can be performed with specific automatic portable
sensors (Pegas et al. 2012). Diffusive portable probes
reveal CO
2
concentrations based on its ability to absorb
infrared radiation at a certain wavelength (2.3–4.6 lm)
such as CO
2
above cited devices, whereas CO concentra-
tions on the basis of electrochemical reactions. Moreover,
CO is a purely outdoor pollutant; therefore, few studies
have been conducted to evaluate the incidence of carbon
monoxide on indoor environments. Chaloulakoua and
Mavroidisb (2002) measured indoor and outdoor CO con-
centrations at a school near the center city of Athens.
Authors found that the indoor and outdoor diurnal con-
centration cycles followed similar patterns and indoor
concentrations showed a mild and slightly delayed
response respect to outdoor concentration changes. In
addition, they observed that CO concentrations measured
during winter were higher than the respective concentra-
tions measured during summer (3.96 and 1.92 ppm,
respectively). These results were linked to the higher traffic
volume and to winter meteorological conditions that favor
the accumulation of pollutants. Similar results and con-
siderations were obtained by Chithra and Shiva Nagendra
(2012) in a study conducted in a school building located
close to an urban roadway in India. Finally Yang et al.
(2009) showed that renovation works had negative effects
on the air quality, as significantly higher concentrations of
CO were registered at schools constructed within 1 year
(1.03 ppm) with respect to those built in previous years
(0.59 ppm). These results might be caused by the new
electric heating systems.
Sulfur dioxide is the main oxide of sulfur found in
indoor air; however, the indoor concentrations determined
inside school buildings are generally lower than those
outdoors (Weschler 2009). The most important sources of
SO
2
are located outdoors, and they can impact the indoor
air of buildings near open coal fires, but the key problem is
that SO
2
is readily absorbed onto indoor material surfaces,
such as emulsion paints, the most important sink for SO
2
(Ashmore and Dimitroulopoulou 2009). Epidemiological
studies on health effects by exposure to SO
2
are compli-
cated by a paucity of representative exposure data and by
confounding factors such as exposure to other indoor pol-
lutants. Ho1wever, several studies provided some useful
data concerning exposure-effect relationships showing that
mortality was observed in populations exposed to 24-h
pollution episodes in which SO
2
concentrations exceeded
300–400 lg/m
3
(0.12–0.15 ppm) (Health Canada 1995).
Sulfur dioxide in indoor environments is continuously
measured by Electron Pulsed Fluorescence SO
2
Analyser.
The operating principle of this instrument is based on
measuring the fluorescence emitted consequently the
absorption of ultraviolet light having wavelength in the
range of 190–230 nm. The wavelength emitted in the range
from 300 to 390 nm is directly proportional to the SO
2
concentration (Lee and Chang 1999; Meininghaus et al.
2003). Moreover, SO
2
concentration can also be deter-
mined using radial passive samplers (Stranger et al. 2008).
Indoor O
3
concentrations can be monitored using an UV
Absorption Ozone Analyzer (Blondeau et al. 2005; Poup-
ard et al. 2005; Sohn et al. 2012) in order to give a real-
time synoptic flow diagram. To perform long-term mea-
surements, instead, it can be used specific diffusive
adsorbing cartridges and the extract analyzed by UV–VIS
spectrophotometry after chemical desorption (Stranger
et al. 2007,2008).
Sulfur dioxide is the less investigated pollutant for the
evaluation of the indoor air quality in schools. Ashmore
and Dimitroulopoulou (2009) found higher concentrations
inside school buildings near open coal fires. Finally,
Spedding (1974) suggested that lower SO
2
indoor con-
centrations could be linked with the capacity of indoor
materials to absorb it. Among the wide variety of materials,
the emulsion paints were identified as the most important
sink for SO
2
.
Carbon dioxide
Outdoor pollutant properties of CO
2
at a global scale are well
documented, but in indoor school environments, it cannot be
considered a pollutant, but represents an important proxy
indicator of air quality. Indoor/outdoor ratio is greater than
one in most of the classrooms, indicating the internal source
prominent, with low level of outdoor intrusions; levels of
600–800 ppm are normally registered in the literature,
indicative of inadequate ventilation rates (Seppanen et al.
1999; Apte et al. 2000), with peaks of 4,000 ppm (Daisey
et al. 2003; Clements-Croome 2006). Exposure to this pol-
lutant is associated with asthma (Mi et al. 2006) and values of
1,000 ppm are associated with a 10–20 % increase in student
absences (Shendell et al. 2004), thus indicating CO
2
Environ Chem Lett
123
Author's personal copy

concentrations a primary variable in the health risk assess-
ment of people in school (Rudnick and Milton 2003).
ASHRAE Standard 62-1989 (1989) suggested indoor
CO
2
levels not exceeding 1,000 ppm s in choosing the right
ventilation for acceptable air quality. With respect to worker
safety, Occupational Safety and Health Administration
(OSHA) has set a permissible exposure limit for CO
2
of
5,000 ppm over an 8-h work day, as also stated by the
American Conference of Governmental Industrial Hygien-
ists threshold limit value (TLV) set to 5,000 ppm for an 8-h
workday, with a ceiling exposure limit of 30,000 ppm for a
10-min period based on acute inhalation data (OSHA 2014).
Occupants in school are the major sources of CO
2
with
level that can vary according to occupancy levels, venti-
lation rate, room structure, air exchange rate (Lee and
Chang 1999,2000; Van Dijken et al. 2006; Fromme et al.
2007;Wa
˚hlinder et al. 1997; Grimsrud et al. 2006; The-
odosiou and Ordoumpozanis 2008; Mumovic et al. 2009).
Real-time monitoring (Ajiboye et al. 2006) showed wide
variations during the day in CO
2
levels registered, with
increases in the beginning of the lessons, during physical
activities (Almeida et al. 2011), peaking until time breaks
started when windows are opened and adequate ventilation
assured (Fromme et al. 2007; Yang et al. 2009; De Giuli
et al. 2012; Pegas et al. 2012) as shown in Fig. 3.
Moreover, Park et al. (2011) showed higher CO
2
con-
centrations in winter because the classrooms were not well
ventilated in this season with respect to summer. Since the
1950s, atmospheric CO
2
level measurements have been
made on air samples by NDIR for real-time monitoring of
CO and CO
2
levels with specific automatic and auto-cali-
brating portable instruments (Lee and Chang 1999; Chal-
oulakoua and Mavroidisb 2002; Yang et al. 2009; Pegas
et al.2010;Parketal.2011; Smedje et al. 2011; Pegas et al.
2012; Sohn et al. 2012). However, the precision of such
real-time measurements decreases rapidly for small air
samples, as in the case for air extracted from ice cores that
are better analyzed with HRGC/MS.
Ozone
Also outdoor pollutant properties of O
3
at a global scale are
well documented as its concentration depend on the
exchange between upper and lower layers of atmosphere
and on photochemical reactions involving nitrogen oxides
and VOCs. Indoor/outdoor ratio is much lower than one in
school (in the range 0.13–0.8) (Gold et al. 1996; Weschler
2000; Blondeau et al. 2005; Mendell and Health 2005;
Poupard et al. 2005; Stranger et al. 2007,2008; Mejı
´a et al.
2011), for almost two reasons: O
3
reacts rapidly with
indoor surfaces as well as by gas-phase reactions with
some VOCs (Weschler 2006), the internal sources are
insignificant, with high level of outdoor intrusions
(Weschler 2000) but, generally, O
3
indoor concentrations
are often below the detection limit (Grøntoft and Ray-
chaudhuri 2004). Indoor sources of O
3
are nowadays some
office equipment, primarily laser printers and copiers and
electrostatic air cleaners (Leovic et al. 1996; Destaillats
et al. 2008). Moreover, higher indoor O
3
concentrations
were found in schools located in areas affected by indus-
trial or urban pollution (Mi et al. 2006; Mejı
´a et al. 2011)
and an high correlation between outdoor and indoor con-
centration there exist as indoor concentrations increased
more rapidly when windows/doors were open and outdoor
O
3
concentrations increased (Gold et al. 1996). These
results confirm that O
3
in indoor environments mostly
comes from outdoor sources and the air exchange rate
plays an important role.
Indoor O
3
levels are dependent on the generation rate,
leakage, ventilation, degree of mixing and air filtration
(Gold et al. 1996) and its decomposition rate is dependent
on the quantity and type of materials in a building and the
presence of organic chemicals characterized by highly
reactive unsaturated carbon–carbon bonds VOCs coming
from soft woods, carpets, linoleum, paints, polishes,
cleaning products and air fresheners, soiled fabrics, soiled
ventilation filters and the occupants themselves (Brown
et al. 1994; Wolkoff 1995; Hodgson and Levin 2003;
Weschler 2006).
Many toxicological and field studies of both adults and
children (Tager 1999; Lee et al. 2004) established the short-
term reversible effects of O
3
on lung function decrements,
respiratory-related hospital admissions, school absence,
restricted activity days, asthma-related emergency depart-
ment visits and premature mortality (Gold et al. 1996;
Hubbell et al. 2005; Weschler 2006). Moreover, ozone/
terpene reactions (as used in cleaning agents) produce
Fig. 3 Classroom CO
2
concentrations during a typical occupation
period (Pegas et al. 2012)
Environ Chem Lett
123
Author's personal copy

strong airway irritants, like formaldehyde, acrolein, perox-
yactyl nitrate, hydroperoxides with known adverse health
effects (Wolkoff et al. 1999; Clausen et al. 2001; Wilkins
et al. 2001; Rohr et al. 2002,2003; Weschler 2006).
Real-time O
3
monitoring can be performed by an UV
absorption Ozone Analyzer (Blondeau et al. 2005; Poupard
et al. 2005; Sohn et al. 2012), but for long-term measure-
ments, specific diffusive adsorbing cartridges can be used,
using chemical desorption and formation of an absorbing
molecule quantified by UV–VIS spectrophotometry
(Stranger et al. 2007,2008). This latter technique can
achieve lower limit of detection, due to its pre-concentra-
tion capacity.
Conclusion
The main goal of this review was to summarize remarkable
findings about air quality inside school buildings. More
specifically, chemical pollutants, related sources and
monitoring methodologies were reported. The outcomes
provide suggestive evidence that certain conditions, com-
monly found in schools, can have adverse effects on the air
quality and therefore on occupant’s health. In particular, it
was highlighted that the location, the age and air-tightness
of school buildings, the room design, the ventilation rate,
the building and furnishing materials, the occupant’s
activities and outdoor pollution play an important role on
the indoor pollutants concentrations. Therefore, in order to
safeguard the health of the occupants and in particular of
children that are more sensitive to environmental pollutants
some good practices should be followed. These actions
include the construction of school buildings equipped with
adequate ventilation systems to improve air exchange as
well as the use of low-emitting building and furniture
materials. Moreover, indoor concentrations of many pol-
lutants are strongly influenced by outdoor sources so it is
important that schools are not located in areas affected by
high traffic or industrial pollution in order to improve air
quality and reduce the impact on students’ health. At this
regard, several States are nowadays working to define
guidelines for suggesting best practices in order to improve
air quality inside school buildings, for defining reference
values and for regulating the control methodologies. This
need arises from the lack of available reference values for
most of the pollutants monitored in indoor environments
(WHO 2010).
References
Abdel-Salam M (2006) Aerosol sampling methods in workplace and
ambient environments. J Aerosol Med 19:434–455
Ajiboye P, White M, Graves H, Ross D (2006) Building research
establishment for office of the Deputy Prime Minister: London.
Ventilation and indoor air quality in schools—guidance report
202825
Alm S (1999) Personal exposures of pre-school children to carbon
monoxide and nitrogen dioxide in urban air. Dissertation,
National Public Health Institute A19/99, Kuopio, Finland
Alm S, Reponen A, Mukala K, Pasanen P, Tuomisto J, Jantunen MJ
(1994) Personal exposures of preschool children to carbon
monoxide: roles of ambient air quality and gas stoves. Atmos
Environ 28:3577–3588
Almeida SM, Canha N, Silva A, Freitas MC, Pegas P, Alves C,
Evtyugina M, Pio CA (2011) Children exposure to air particulate
matter in indoor of Lisbon primary schools. Atmos Environ
45:7594–7599
Angiuli L, Bruno P, Caputi M, Caselli M, De Gennaro G, De Rienzo
M (2003) Radial passive samplers for air quality monitoring in
field comparison with a BTEX automatic analyser preliminary
results. Fresenius Environ Bull 12(10):1167–1172
Appatova AS, Ryan PH, LeMasters GK, Grinshpun SA (2008) Proximal
exposure of public schools and students to major roadways: a
nationwide U.S. survey. J Environ Plan Manag 51:631–646
Apte MG, Fisk WJ, Daisey JM (2000) Associations between indoor
(CO2) concentrations and sick building syndrome symptoms in
US Office Buildings: an analysis of the 1994–1996 BASE Study
Data (LBNL 44385). Indoor Air 10:246–257
Ashmore MR, Dimitroulopoulou C (2009) Personal exposure of
children to air pollution. Atmos Environ 43:128–141. doi:10.
1016/j.atmosenv.2008.09.024
ASHRAE Standard 62 (1989) American Society of Heating, Refrig-
erating and Air-conditioning Engineers. Ventilation for accept-
able indoor air quality. ASHRAE Standard 62, Atlanta
Barro R, Regueiro J, Llompart M, Garcia-Jares C (2009) Analysis of
industrial contaminants in indoor air: Part 1. Volatile organic
compounds, carbonyl compounds, polycyclic aromatic hydro-
carbons and polychlorinated biphenyls. J Chromatogr A
1216:540–566
Bartlett KH, Kennedy SM, Brauer M, Netten CV, Dill B (2004)
Evaluation and determinants of airborne bacterial concentrations
in school classrooms. J Occup Environ Hyg 1:639–647
Basu R, Samet JM (1999) A review of the epidemiological evidence
on health effects of nitrogen dioxide exposure from gas stoves.
J Environ Med 1:173–187. doi:10.1002/jem.28
Bertoni G, Ciuchini C, Pasini A, Tappa R (2002) Monitoring of
ambient BTX at Monterotondo (Rome) and indoor-outdoor
evaluation in school and domestic sites. J Environ Monit
4:903–909. doi:10.1039/b206959h
Blondeau P, Iordache V, Poupard O, Genin D, Allard F (2005)
Relationship between outdoor and indoor air quality in eight
French schools. Indoor Air 15:2–12. doi:10.1111/j.1600-0668.
2004.00263.x
Branis M, Safra
´nek J (2011) Characterization of coarse particulate
matter in school gyms. Environ Res 111:485–491
Branis M, Safra
´nek J, Hytychova
´A (2009) Exposure of children to
airborne particulate matter of different size fractions during
indoor physical education at school. Build Environ
44:1246–1252. doi:10.1016/j.buildenv.2008.09.010
Brown S, Sim M, Abramson M, Gray C (1994) Concentrations of
volatile organic compounds in indoor air—a review. Indoor Air
4:123–134
Bruno P, Caputi M, Caselli M, de Gennaro G, de Rienzo M (2005)
Reliability of a BTEX radial diffusive sampler for thermal
desorption: field measurements. Atmos Environ 39:1347–1355
Bruno P, Caselli M, de Gennaro G, Iacobellis S, Tutino M (2008)
Monitoring of volatile organic compounds in non-residential
indoor environments. Indoor Air 18:250–256
Environ Chem Lett
123
Author's personal copy

Burnett RT, Dales RE, Brooks JR, Raizenne ME, Krewski D (1997)
Association between ambient carbon monoxide levels and
hospitalizations for congestive heart failure in the elderly in 10
Canadian cities. Epidemiology 8:162–167
Burnett RT, Cakmak S, Raizenne ME, Stieb D, Vincent R, Krewski
D, Brooks JR, Philips O, Ozkayanak H (1998) The association
between ambient carbon monoxide levels and daily mortality in
Toronto, Canada. J Air Waste Manag Assoc 48:689–700
Burton BT (1997) Volatile organic compounds. In: Bardana EJ,
Montanaro A (eds) Indoor air pollution and health. Marcel
Dekker, New York, pp 127–153
Chaloulakoua A, Mavroidisb I (2002) Comparison of indoor and
outdoor concentrations of CO at a public school. Evaluation of
an indoor air quality model. Atmos Environ 36:1769–1781
Chao CY, Wong KK (2002) Residential indoor PM 10 and PM 2.5 in
Hong Kong and their elementalcomposition. Atmos Environ
36:265–277
Chithra VS, Shiva Nagendra SM (2012) Indoor air quality investi-
gations in a naturally ventilated school building located close to
an urban roadway in Chennai, India. Build Environ 54:159–167.
doi:10.1016/j.buildenv.2012.01.016
Clausen PA, Wilkins CK, Wolkoff P, Nielsen GD (2001) Chemical
and biological evaluation of a reaction mixture of R-(?)-
limonene/ozone—formation of strong airway irritants. Environ
Int 26(7–8):511–522
Clements-Croome D (2006) Ventilation rates in schools. Build
Environ 43(3):362–367
Corgnati SP, Filippi M, Viazzo S (2007) Perception of the thermal
environment in high school and university classrooms: sub-
jective preferences and thermal comfort. Build Environ
42:951–959
Coward S, Llewellyn J, Raw G, Brown V, Crump D, Ross D (2001)
Indoor air quality in homes in England. BRE report BR 433.
CRC Ltd, Watford, UK
Croome DJC, Awbi HB, Biro ZB, Kochhar N, Williams M (2008)
Ventilation rates in schools. Build Environ 43:362–367
Daisey JM, Angell WJ, Apte MG (2003) Indoor air quality,
ventilation and health symptoms in schools: an analysis of
existing information. Indoor Air 13:53–64
Dambruoso et al. (2013) School air quality: pollutants, monitoring
and toxicity published in ‘Pollutant diseases, remediation and
recycling’, Series: environmental chemistry for a sustainable
world, vol 4. doi:10.1007/978-3-319-02387-8_1
Damek-Poprawa M, Sawicka-Kapusta K (2003) Damage to the liver,
kidney, and testis with reference to burden of heavy metals in
yellow-necked mice from areas around steelworks and zinc
smelters in Poland. Toxicology 186:1–10
Daresta BE, Liuzzi VC, de Gennaro G, De Giorgi C, De Luca F,
Caselli M (2010) Evaluation of the toxicity of PAH mixtures and
organic extract from Apulian particulate matter by the model
system ‘Caenorhabditis elegans’. Fresen Environ Bull
19:2002–2005
De Giuli V, Da Pos O, De Carli M (2012) Indoor environmental
quality and pupil perception in Italian primary schools. Build
Environ 56:335–345. doi:10.1016/j.buildenv.2012.03.024
Destaillats H, Maddalena RL, Singer BC, Hodgson AT, McKone TE
(2008) Indoor pollutants emitted by office equipment. A review
of reported data and information needs. Atmos Environ
42:1371–1388
Diapouli E, Chaloulakou A, Mihalopoulos N, Spyrellis N (2008)
Indoor and outdoor PM mass and number concentrations at
schools in the Athens area. Environ Monit Assess 136:13–20.
doi:10.1007/s10661-007-9724-0
Dijken FV, Bronswijk JV, Sundell J (2005) Indoor environment in
Dutch primary schools and health of the pupils. In: Proceedings
of indoor air, Beijing, China, vol 1, p 623
Dimitroulopoulou C, Crump D, Coward SKD, Brown B, Squire R,
Mann H, White M, Pierce B, Ross D (2005) Ventilation, air
tightness and indoor air quality in new homes. BR477. Building
Research Establishment Press, Garston/Watford/Hertfordshire
Ekmekcioglu D, Keskin SS (2007) Characterization of indoor air
particulate matter in selected elementary schools in Istanbul,
Turkey. Indoor Built Environ 16:169–176. doi:10.1177/
1420326X07076777
Englert N (2004) Fine particles and human health—a review of
epidemiological studies. Toxicol Lett 149:235–242
Fan Z, Lioy P, Weschler CJ, Fiedler N, Kipen H, Zhang J (2003)
Ozone-initiated reactions with mixtures of volatile organic
compounds under simulated indoor conditions. Environ Sci
Technol 37:1811–1821
Faustman EM, Silbernagel SM, Fenske RA, Burbacher TM, Ponce
RA (2000) Mechanisms underlying children’s susceptibility to
environmental toxicants. Environ Health Perspect 108(Suppl
1):13–21
Forbes L, Patel MD, Rudnicka AR, Cook DG, Bush T, Stedman JR,
Strachan DP, Anderson HR (2009) Chronic exposure to outdoor
air pollution and diagnosed cardiovascular disease: meta-
analysis of three large cross-sectional surveys. Environ Health
8(30):1–9
Fraga S, Ramos E, Martins A, Samu
´dio MJ, Silva G, Guedes J,
Oliveira Fernandes E, Barros H (2008) Indoor air quality and
respiratory symptoms in Porto Schools. Rev Port Pneumol
14(4):487–507
Fromme H, Twardella D, Dietrich S, Heitmann D, Schierl R, Liebl B,
Ruden H (2007) Particulate matter in the indoor air of
classrooms-exploratory results from Munich and surrounding
area. Atmos Environ 41:854–866. doi:10.1016/j.atmosenv.2006.
08.053
Fromme H, Diemer J, Dietrich S, Cyrys J, Heinrich J, Lang W,
Kiranoglua M, Twardella D (2008) Chemical and morphological
properties of particulate matter (PM10, PM2.5) in school
classrooms and outdoor air. Atmos Environ 42:6597–6605.
doi:10.1016/j.atmosenv.2008.04.047
Gemenetzis P, Moussas P, Arditsoglou A, Samara C (2006) Mass
concentration and elemental composition of indoor PM2.5 and
PM 10 in University Rooms in Thessaloniki, Northern Greece.
Atmos Environ 40:3195–3206
Godwin C, Batterman S (2007) Indoor air quality in Michigan
schools. Indoor Air 17:109–121
Gold DR, Allen G, Damokosh A, Serrano P, Hayes C, Castiilejos M
(1996) Comparison of outdoor and classroom ozone exposures
for school children in Mexico City. J Air Waste Manag Assoc
46:335–342
Goyal R, Khare M (2011) Indoor air quality modeling for PM10,
PM2.5, and PM1.0 in naturally ventilated classrooms of an urban
Indian school building. Environ Monit Assess 176:501–516.
doi:10.1007/s10661-010-1600-7
Green RS, Smorodinsky S, Kim JJ, McLaughlin R, Ostro B (2004)
Proximity of California public schools to busy roads. Environ
Health Perspect 112:61–66
Grimsrud D, Bridges B, Schulte R (2006) Continuous measurements
of air quality parameters in schools. Build Res Inform
34:447–458
Grøntoft T, Raychaudhuri MR (2004) Compilation of tables of
surface deposition velocities of O3, NO2 and SO2 to a range of
indoor surfaces. Atmos Environ 38:533–544
Gul H, Gaga EO, Do
¨g
˘erog
˘lu T, O
¨zden O, Ayvaz O, O
¨zel S, Gu
¨ngo
¨rG
(2011) Respiratory health symptoms among students exposed to
different levels of air pollution in a Turkish city. Int J Environ
Res Public Health 8:1110–1125. doi:10.3390/ijerph8041110
Guo YL, Lin YC, Sung FC, Huang SL, Ko YC, Lei JS, Su HJ, Shaw
CK, Lin RS, Dockery DW (1999) Climate, traffic-related air
Environ Chem Lett
123
Author's personal copy

pollutants, and asthma prevalence in middle-school children in
Taiwan. Environ Health Perspect 107:1001–1006
Guo H, Lee SC, Chan LY, Li WM (2004) Risk assessment of
exposure to volatile organic compounds in different indoor
environments. Environ Res 94:57–66
Hanoune B, LeBris T, Allou L, Marchand C, Calve LS (2006)
Formaldehyde measurements in libraries: comparison between
Infrared diode laser spectroscopy and a DNPH-derivatization
method. Atmos Environ 40:5768–5775
Health Canada (1995) Exposure guidelines for residential indoor air
quality. Report of the Federal- Provincial Advisory Committee on
environmental and occupational health. Health Canada Publica-
tions—Communications, Ottawa, ON. Available at: http://www.
hc-sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/air/exposure-
exposition/exposure-exposition-eng.pdf. Accessed 20 Nov 2012
Hochstetler HA, Yermakov M, Reponen T, Ryan PH, Grinshpun SA
(2011) Aerosol particles generated by diesel-powered school
buses at urban schools as a source of children’s exposure. Atmos
Environ 45:1444–1453. doi:10.1016/j.atmosenv.2010.12.018
Hodgson AT (1995) A review and a limited comparison of methods
for measuring total volatile organic compounds in indoor Air.
Indoor Air 5(4):247–257
Hodgson AT, Levin H (2003) Volatile organic compounds in indoor
air: a review of concentrations measured in North America since
1990. Report LBNL-51715. Berkeley National Laboratory,
Lawrence. Available at: http://energy.lbl.gov/ie/pdf/LBNL-
51715.pdf. Accessed 20 Nov 2012
Hodgson MJ, Frohlinger J, Permar E, Tidwell C, Traven ND,
Olenchock SA, Karpf M (1991) Symptoms and micro-environ-
mental measures in non-problem buildings. J Occup Med
33(4):527–533
Hong H, Cheng LS, Jun-Ji C, Chang-Wei Z, Xin-Geng C, Shao-Jia F
(2007) Characteristics of indoor/outdoor PM2.5 and elemental
components in generic urban, roadside and industrial plant areas
of Guangzhou City China. J Environ Sci 19:35–43
Huang YC, Ghio AJ (2006) Vascular effects of ambient pollutant
particles and metals. Curr Vasc Pharmacol 4:199–208
Huang H, Zou C, Cao J, Tsang P, Zhu F, Yu C, Xue S (2012) Water-
soluble ions in PM 2.5 on the qianhu campus of Nanchang
University, Nanchang city: indoor–outdoor distribution and
source implications. Aerosol Air Qual Res 12:435–443
Hubbell BJ, Hallberg A, McCubbin DR, Post E (2005) Health related
benefits of attaining the 8-hr ozone standard. Environ Health
Perspect 113:73–82
Hulin M, Annesi-Maesano I, Caillaud D (2011) Indoor air quality at
school and allergy and asthma among schoolchildren. Differ-
ences between rural and urban areas. Rev Fr D’allergol
51:419–424. doi:10.1016/j.reval.2011.01.002
IARC (2012) Monographs on the evaluation of carcinogenicity to
humans, volume 100 F, formaldehyde, 2012. U.S. Department of
Health and Human Services Public Health Service, National
Toxicology Program, Report on Carcinogens, 12th edition
ISO 16000-3: (2011) Indoor air-part 3: determination of formalde-
hyde and other carbonyl compounds in indoor air and test
chamber air-active sampling method
Janssen NAH, Hoek G, Harssema H, Brunekreef B (1997) Childhood
exposure to PM10: relation between personal, classroom, and
outdoor concentrations. Occup Environ Med 54(12):888–894
Janssen NAH, van Vliet PHN, Aarts F, Harssema H, Brunekreef B
(2001) Assessment of exposure to traffic related air pollution of
children attending schools near motorways. Atmos Environ
35:3875–3884
Jo WK, Kim JD (2010) Personal exposure of graduate students
attending the college of natural sciences or social sciences to
volatile organic compounds on campus. Chemosphere
81:1272–1279
Jones AP (1999) Indoor air quality and health. Atmos Environ
33(28):4535–4564
Kotzias D (2005) Indoor air and human exposure assessment—needs
and approaches. Exp Toxicol Pathol 57:5–7
Koutrakis P, Briggs SLK, Leaderer BP (1992) Source apportionment
of indoor aerosols in Suffolk and Onondaga Counties, New
York. Environ Sci Technol 23:521–527
Lai SC, Ho KF, Zhang YY, Lee SC, Huang Y, Zou SC (2010)
Characteristics of residential indoor carbonaceous aerosols: a
case study in guangzhou, pearl river delta region. Aerosol Air
Qual Res 10:472–478
Lee SC, Chang M (1999) Indoor air quality investigations at five
classrooms. Indoor Air 9:134–138
Lee SC, Chang M (2000) Indoor and outdoor air quality investigation
at schools in Hong Kong. Chemosphere 41:109–113
Lee K, Parkhurst WJ, Xue J, Ozkaynak A, Neuberg D, Spengler JD
(2004) Outdoor/indoor/personal ozone exposures of children in
Nashville, Tennessee. Air Waste Manag Assoc 54:352–359
Leovic KW, Sheldon LS, Whitaker DA, Hetes RG, Calcagni JA,
Baskir JN (1996) Measurement of indoor air emissions from dry-
process photocopy machines. J Air Waste Manag Assoc
46(9):821–829
Li TH, Turpin BJ, Shields HC, Weschler CJ (2002) Indoor hydrogen
peroxide derived from ozone/d-limonene reactions. Environ Sci
Technol 36:3295–3302
Liuzzi VC, Daresta BE, de Gennaro G, De Giorgi C (2011) Different
effects of polycyclic aromatic hydrocarbons in artificial and in
environmental mixtures on the free living nematode C. elegans.
J Appl Toxicol 32:45–50
Long CM, Suh HH, Koutrakis P (2000) Characterization of indoor
particle sources using continuous mass and size monitors. J Air
Waste Manag Assoc 50:1236–1250
MacIntosh DL, Minegishi T, Fragala MA, Allen JG, Coghlan KM,
Stewart JH, McCarthy JF (2012) Mitigation of building-related
polychlorinated biphenyls in indoor air of a school. Environ
Health 11:24. doi:10.1186/1476-069X-11-24
Martuzevicius D, Grinshpun SA, Lee T, Hu S, Biswas P, Reponen T,
LeMasters G (2008) Traffic-related PM 2.5 aerosol in residential
houses located near major highways: indoor versus outdoor
concentrations. Atmos Environ 42:6575–6585
Meininghaus R, Kouniali A, Mandin C, Cicolella A (2003) Risk
assessment of sensory irritants in indoor air a case study in a
french school. Environ Int 28:553–557
Mejı
´a JF, Low Choy S, Mengersen K, Morawska L (2011)
Methodology for assessing exposure and impacts of air pollu-
tants in school children: data collection, analysis and health
effects—a literature review. Atmos Environ 45:813–823. doi:10.
1016/j.atmosenv.2010.11.009
Mendell JM, Health GA (2005) Do indoor pollutants and thermal
conditions in schools influence student performance? A critical
review of the literature. Indoor Air 15:27–52
Mentese S, Gullu G (2006) Variations and sources of formaldehyde
levels in residential indoor air in Ankara, Turkey. Indoor Built
Environ 15:273–281
Mi YH, Norback D, Tao J, Mi YL, Ferm M (2006) Current asthma
and respiratory symptoms among pupils in Shanghai, China:
influence of building ventilation, nitrogen dioxide, ozone, and
form aldehyde in classrooms. Indoor Air 16(6):454–464. doi:10.
1111/j.1600-0668.2006.00439.x
Mølhave L, Bach B, Pedersen OF (1986) Human reactions to low
concentrations of volatile organic compounds. Environ Int
12(1–4):167–175
Mullen NA, Bhangar S, Hering SV, Kreisberg NM, Nazaroff WW
(2011) Ultrafine particle concentrations and exposures in six
elementary school classrooms in northern California. Indoor Air
21:77–87. doi:10.1111/j.1600-0668.2010.00690.x
Environ Chem Lett
123
Author's personal copy

Mumovic D, Palmer J, Davies M, Orme M, Ridley I, Oreszczyn T,
Jud C, Critchlow R, Medina HA, Pilmoor G, Pearson C, Way P
(2009) Winter indoor air quality, thermal comfort and acoustic
performance of newly built secondary schools in England. Build
Environ 44:1466–1477. doi:10.1016/j.buildenv.2008.06.014
Nadadur SS, Miller A, Hopke PK, Gordon T, Vedal S, Vandenberg JJ,
Costa DL (2007) The complexities of air pollution regulation:
the need for an integrated research and regulatory perspective.
Toxicol Sci 100:318–327
NIOSH/IPCS (2004) International chemical safety cards: formaldehyde
Oeder S, Dietrich S, Weichenmeier I, Schober W, Pusch G, Jo
¨rres
RA, Schierl R, Nowak D, Fromme H, Behrendt H, Buters J
(2012) Toxicity and elemental composition of particulate matter
from outdoor and indoor air of elementary schools in Munich,
Germany. Indoor Air 22:148–158
OEHHA (2008) Office of environmental health hazard assessment,
Sacramento, CA. Air toxics hot spots, risk assessment guide-
lines, technical support document for the derivation of non
cancer reference exposure levels. Appendix D. Available: http://
oehha.ca.gov/air/hot_spots/2008/NoncancerTSD_final.pdf.
Accessed 20 Nov 2012
Oie L, Nafstad P, Botten G (1993) Infants exposure to NO2. In:
Proceedings of indoor air’93, Helsinki, Finland, vol 3, p 183
Olson DA, Turlington J, Duvall RM, McDow SR, Stevens CD,
Williams R (2008) Indoor and outdoor concentrations of organic
and inorganic molecular markers: source apportionment of PM
2.5 using low- volume samples. Atmos Environ 42:1742–1751
Ozkaynak H, Xue J, Spengler JD, Wallace LA, Pellizzari ED, Jenkins
P (1996) Personal exposure to airborne particles and metals:
results from the particle TEAM study in Riverside, California.
J Expo Anal Environ Epidemiol 6:57–78
Park JC, Chung MH, Rhee EK (2011) Field survey on the indoor
environment of elementary schools for planning of environment
friendly school facilities. J Asian Archit Build Eng 10(2):461–468
Pegas PN, Evtyugina MG, Alves CA, Nunes T, Cerqueira M, Franchi
M, Pio C, Almeida SM, Freitas M (2010) Outdoor/indoor air
quality in primary schools in Lisbon: a preliminary study. Quim
Nova 33(5):1145–1149
Pegas PN, Alves CA, Evtyugina MG, Nunes T, Cerqueira M, Franchi
M, Pio CA, Almeida SM, Freitas MC (2011a) Indoor air quality
in elementary schools of Lisbon in spring. Environ Geochem
Health 33(5):455–468
Pegas PN, Alves CA, Evtyugina MG, Nunes T, Cerqueira M, Franchi
M, Pio CA, Almeida SM, Verde SC, Freitas MC (2011b)
Seasonal evaluation of outdoor/indoor air quality in primary
schools in Lisbon. J Environ Monit 13(3):657–667
Pegas PN, Nunes T, Alves CA, Silva JR, Vieira SLA, Caseiro A, Pio
CA (2012) Indoor and outdoor characterisation of organic and
inorganic compounds in city centre and suburban elementary
schools of Aveiro, Portugal. Atmos Environ 55:80–89
Pennequin-Cardinal A, Plaisance A, Locoge N, Ramalho O, Kirchner
S, Galloo JC (2005) Dependence on sampling rates of radiello
diffusion sampler for BTEX measurements with concentration
level and exposure time. Talanta 65:1233–1240
Pope CA, Ezzati M, Dockery DW (2009) Fine-particulate air
pollution and life expectancy in the United States. N Engl J
Med 360:376–386
Poupard O, Blondeau P, Iordache V, Allard F (2005) Statistical
analysis of parameters influencing the relationship between
outdoor and indoor air quality in schools. Atmos Environ
39:2071–2080
Prieditis H, Adamson IYR (2002) Comparative pulmonary toxicity of
various soluble metals found in urban particulate dust. Exp Lung
Res 28:563–576
Priscilla N, Pegas M, Evtyugina G, Alves CA, Nunes T, Cerqueira M,
Franchi M, Pio C (2010) Outdoor/indoor air quality in primary
schools in Lisbon: a preliminary study. Quim Nova
33(5):1145–1149
Ramachandran G, Adgate JL, Banerjee S, Church TR, Jones D,
Fredrickson A et al (2005) Indoor air quality in two urban elementary
schools-measurements of airborne Fungi, Carpet allergens, CO2,
temperature, and relative humidity. J Occup Environ Hyg 2:553–566
Raub JA, Mathieu-Nolf M, Hampson NB, Stephen RT (2000) Carbon
monoxide poisoning—a public health perspective. Toxicology
145:1–14
Raysoni AU, Sarnat JA, Sarnat SE, Garcia JH, Holguin F, Lue
`vano
SF, Li WW (2011) Binational school-based monitoring of
traffic-related air pollutants in El Paso, Texas (USA) and Ciudad
Jua
´rez, Chihuahua (Me
´xico). Environ Pollut
159(10):2476–2486. doi:10.1016/j.envpol.2011.06.024
Reich BJ, Fuentes M, Burke J (2009) Analysis of the effects of
ultrafine particulate matter while accounting for human expo-
sure. Environmetrics 20:131–146
Righi E, Aggazzotti G, Fantuzzi G, Ciccarese PG (2002) Air quality
and well-being perception in subjects attending university
libraries in Modena (Italy). Sci Total Environ 286:41–50
Rohr AC, Wilkins CK, Clausen PA, Hammer M, Nielsen GD,
Wolkoff P (2002) Upper airway and pulmonary effects of
oxidation products of (?)-alpha-pinene, d-limonene, and iso-
prene in BALB/c mice. Inhal Toxicol 14(7):663–684
Rohr AC, Shore SA, Spengler JD (2003) Repeated exposure to isoprene
oxidation products causes enhanced respiratory tract effects in
multiple murine strains. Inhal Toxicol 15(12):1191–1207
Rudnick S, Milton DK (2003) Risk of indoor airborne infection
transmission estimated from carbon dioxide concentration.
Indoor Air 13:237–245
Sager TM, Castranova V (2009) Surface area of particle administered
versus mass in determining the pulmonary toxicity of ultrafine
and fine carbon black: comparison to ultrafine titanium dioxide.
Part Fibre Toxicol 6:1–12
Saraga DE, Maggos T, Helmis CG, Michopoulos J, Bartzis JG,
Vasilakos C (2010) PM1 and PM 2.5 ionic composition and
VOCs measurements in two typical apartments in Athens,
Greece: investigation of smoking contribution to indoor air
concentrations. Environ Monit Assess 67:321–331
Sarwar G, Corsi R, Allen D, Weschler CJ (2003) The significance of
secondary organic aerosol formation and growth in buildings:
experimental and computational evidence. Atmos Environ
37:1365–1381
Scheepers PTJ, Konings J, Demirel G, Gaga EO, Anzion R, Peer PGM,
Dogeroglu T, Ornektekin S, van Doorn W (2010) Determination
of exposure to benzene, toluene and xylenes in Turkish primary
school children by analysis of breath and by environmental
passive sampling. Sci Total Environ 408:4863–4870
Scheff PA, Paulius VK, Curtis L, Conroy LM (2000a) Indoor air
quality in a middle school, part II: development of emission
factors for particulate matter and bioaerosols. Appl Occup
Environ Hyg 15:835–842
Scheff PA, Paulius VK, Huang SW, Conroy LM (2000b) Indoor air
quality in a middle school, part I: use of CO2 as a tracer for
effective ventilation. Appl Occup Environ Hyg 15:824–834
Seppanen OA, Fisk WJ, Mendell MJ (1999) Association of ventila-
tion rates and CO2 concentrations with health and other
responses in commercial and institutional buildings. Indoor Air
9(4):226–252
Shaughnessy RJ, Haverinen-Shaughnessy U, Nevalainen A, Mos-
chandreas D (2006) A preliminary study on the association
between ventilation rates in classrooms and student performance.
Indoor Air 16:465–468
Shendell DG, Prill R, Fisk WJ, Apte MG, Blake D, Faulkner D (2004)
Associations between classroom CO2 concentrations and student
attendance in Washington and Idaho. Indoor Air 14:333–341
Environ Chem Lett
123
Author's personal copy

Smedje G, Norback D, Edling C (1997a) Asthma among secondary
schoolchildren in relation to the school environment. Clin Exp
Allergy 27(11):1270–1278. doi:10.1111/j.1365-2222.1997.
tb01171.x
Smedje G, Norback D, Edling C (1997b) Subjective indoor air quality
in schools in relation to exposure. Indoor Air 7:143–150
Smedje G, Mattsson M, Walinder R (2011) Comparing mixing and
displacement ventilation in classrooms: pupils’ perception and
health. Indoor Air 21:454–461. doi:10.1111/j.1600-0668.2011.
00725.x
Smolı
´k J, Doha
´nyosova
´P, Schwarz J, Z
ˇdı
´mal V, Lazaridis M (2008)
Characterization of indoor and outdoor air in a suburban area of
Prague. Water Air Soil Pollut Focus 8:35–47
Sofuoglu A, Kiymet N, Kavcar P, Sofuoglu SC (2010) Polycyclic and
nitro musks in indoor air: a primary school classroom and a
women’s sport center. Indoor Air 20:515–522. doi:10.1111/j.
1600-0668.2010.00674.x
Sofuoglu SC, Aslan G, Inal F (2011) An assessment of indoor air
concentrations and health risks of volatile organic compounds in
three primary schools. Int J Hyg Environ Health 214:38–46.
doi:10.1016/j.ijheh.2010.08.008
Sohn JR, Moon HJ, Ryu SH, Hwang T (2012) Indoor air quality in
school classrooms with mechanical ventilation systems. In:
Proceedings of the 7th international symposium on sustainable
healthy buildings, Seoul, Korea, p 349
Spedding JD (1974) Air pollution. Clarendon Press, Oxford
Stranger M, Potgieter-Vermaak SS, Van Grieken R (2007) Compar-
ative overview of indoor air quality in Antwerp, Belgium.
Environ Int 33:789–797. doi:10.1016/j.envint.2007.02.014
Stranger M, Potgieter-Vermaak SS, Van Grieken R (2008) Charac-
terization of indoor air quality in primary schools in Antwerp,
Belgium. Indoor Air 18:454–463
Szoboszlai Z, Furu E, Angyal A, Szikszai Z, Zs K (2011)
Investigation of indoor aerosols collected at various educational
institutions in Debrecen, Hungary. X-Ray Spectrom 40:176–180.
doi:10.1002/xrs.1323
Tager IB (1999) Air pollution and lung function growth—is it ozone?
Am J Respir Crit Care Med 160:387–389
Theodosiou TG, Ordoumpozanis KT (2008) Energy, comfort and
indoor air quality in nursery and elementary school buildings in
the cold climatic zones of Greece. Energy Build 40:2207–2214.
doi:10.1016/j.enbuild.2008.06.011
Touloumi G, Pocock SJ, Katsouyanni K, Trichopoulos D (1994) Short
term effects of air pollution on daily mortality in Athens: a time-
series analysis. Int J Epidemiol 23:957–967
Tran DT, Alleman LY, Coddeville P, Galloo JC (2012) Elemental
characterization and source identification of size resolved
atmospheric particles in French classrooms. Atmos Environ
54:250–259. doi:10.1016/j.atmosenv.2012.02.021
UBA (2008) Guidelines for indoor air hygiene in school buildings. In:
Dr. Heinz-Jo
¨rn Moriske, Dr. Regine Szewzyk (eds) Federal
Environment Agency (UBA) Innenraumlufthygiene-Kommis-
sion des Umweltbundesamtes. Available at: http://www.umwelt
daten.de/publikationen/fpdf-l/4113.pdf. Accessed 20 Nov 2012
UNI EN ISO (16000-1): (2006) Indoor air—Part 1: general aspects of
sampling strategy
UNI EN ISO (16000-2): (2006) Indoor air—Part 2: sampling strategy
for formaldehyde
UNI EN ISO (16000-5): (2007) Indoor air – Part 5: sampling strategy
for volatile organic compounds (VOCs)
UNI EN ISO (16017-1): (2007) Campionamento ed analisi di
composti organici volatili mediante tubo di adsorbimento/
desorbimento termico/cromatografia gassosa capillare. Parte 1:
Campionamento mediante aspirazione con pompa
UNI EN ISO (16017-2): (2007) Campionamento ed analisi di
composti organici volatili mediante tubo di adsorbimento/
desorbimento termico/cromatografia gassosa capillare. Parte 2:
Campionamento per diffusione
UNI EN ISO (16000-15): (2008) Indoor air—Part 15: sampling
strategy for nitrogen dioxide (NO2)
USEPA (1991) The clean air act. Office of Research and Develop-
ment, Washington, DC
USEPA (2003) Integrated risk information system. USEPA, Wash-
ington, DC. Available: http://www.epa.gov/IRIS/subst/2003
Vaizoglu SA, Aycan S, Deveci MA, Acer T, Bulut B, Bayraktar UD,
Akyollu B, Celik M, Arslan U, Akpinar F, Baris Z, Arslan S,
Deniz A, Didem Evci E, Gu
¨ler C (2003) Determining domestic
formaldehyde levels in Ankara, Turkey. Indoor Built Environ
12:329–335. doi:10.1177/142032603035546
Van Dijken F, Van Bronswijk JEMH, Sundell J (2006) Indoor
environment and pupils’ health in primary schools. Build Res Inf
34(5):437–446
Van Roosbroeck S, Jacobs J, Janssen NAH, Oldenvening M, Hoek G,
Brunekreef B (2007) Long-term personal exposure to PM2.5
soot and NOx in children attending schools near busy roads a
validation study. Atmos Environ 41:3381–3394. doi:10.1016/j.
atmosenv.2006.12.023
Venn A, Lewis S, Cooper M, Hubbard R, Hill I, Boddy R, Bell M,
Britton J (2000) Local road traffic activity and the prevalence,
severity, and persistence of wheeze in school children: combined
cross sectional and longitudinal study. Occup Environ Med
57:152–158
Wahab SAA, Basma Y (2004) Total suspended dust and heavy metal
levels emitted from a workplace compared with nearby residen-
tial houses. Atmos Environ 38:745–750
Wa
˚hlinder R, Norba
¨ck D, Wieslander G, Smedje G, Erwall C (1997)
Nasal mucosal swelling in relation to low air exchange rate in
schools. Indoor Air 7:198–205
Wainman T, Zhang J, Weschler CJ, Lioy PJ (2000) Ozone and
limonene in indoor air: a source of submicron particle exposure.
Environ Health Perspect 108:1139–1145
Wargocki P, Wyon DP, Matysiak B, Irgens S (2005) The effects of
classroom air temperature and outdoor air supply rate on the
performance of school work by children. In: Proceedings of
indoor air 2005, Beijing, vol 1, p 368
Weichenthal S, Dufresne A, Infante-Rivard C, Joseph L (2008)
Characterizing and predicting ultrafine particle counts in Cana-
dian classrooms during the winter months: model development
and evaluation. Environ Res 106:349–360. doi:10.1016/j.envres.
2007.08.013
Weschler CJ (2000) Ozone in indoor environments: concentration and
chemistry. Indoor Air 10:269–288
Weschler CJ (2006) Ozone’s impact on public health: contributions
from indoor exposures to ozone and products of ozone-initiated
chemistry. Environ Health Perspect 114(10):1489–1496. doi:10.
1289/ehp.9256
Weschler CJ (2009) Changes in indoor pollutants since the 1950s.
Atmos Environ 43:153–169
Weschler GJ, Shields HC (1999) Indoor ozone/terpene reactions as a
source of indoor particles. Atmos Environ 33:2301–2312
WHO, World Health Organisation (2006a) Air quality guidelines—
global update 2005. WHO Regional Office for Europe. Available
at: http://www.euro.who.int/__data/assets/pdf_file/0005/78638/
E90038.pdf. Accessed 20 Nov 2012
WHO, World Health Organization (2006b) Principles for evaluating
health risks in children associated with exposure to chemicals.
Available at: http://www.who.int/ipcs/publications/ehc/ehc237.
pdf. Accessed 20 Nov 2012
WHO, World Health Organization (2010) Guidelines for indoor air
quality: selected pollutants. ISBN 978 92 890 0213 4. Available
at: http://www.euro.who.int/__data/assets/pdf_file/0009/128169/
e94535.pdf
Environ Chem Lett
123
Author's personal copy

Wild P, Bourgkard E, Paris C (2009) Lung cancer and exposure to
metals: the epidemiological evidence. Methods Mol Biol
472:139–167
Wilkins CK, Clausen PA, Wolkoff P, Larsen ST, Hammer M, Larsen
K, Hansen V, Nielsen GD (2001) Formation of strong airway
irritants in mixtures of isoprene/ozone and isoprene/ozone/
nitrogen dioxide. Environ Health Perspect 109:937–941
Wolkoff P (1995) Volatile organic compounds-sources, measure-
ments, emissions, and the impact on indoor air quality. Indoor
Air 5(suppl 3):9–73
Wolkoff P, Clausen PA, Wilkins CK, Hougaard KS, Nielsen GD
(1999) Formation of strong airway irritants in a model mixture of
(?)-alpha-pinene/ozone. Atmos Environ 33(5):693–698
Wu YC, Batterman SA (2006) Proximity of schools in detroit,
michigan to automobile and truck traffic. J Expo Sci Environ
Epidemiol 16:457–470
Wu Q, Baek SY, Fang M, Chang YS (2010) Distribution and fate of
polybrominated diphenyl ethers in indoor environments of
elementary schools. Indoor Air 20:263–270. doi:10.1111/j.
1600-0668.2010.00652.x
Yamashita S, Kume K, Horiike T, Honma N, Masahiro F, Amagai T
(2012) Emission sources and their contribution to indoor air
pollution by carbonyl compounds in a school and a residential
building in Shizuoka, Japan. Indoor Built Environ 21(3):392–402
Yang W, Sohn J, Kim J, Son B, Park J (2009) Indoor air quality
investigation according to age of the school buildings in Korea.
J Environ Manag 90:348–354
Zanobetti A, Schwartz J (2005) The effect of particulate air pollution
on emergency admissions for myocardial infarction: a multicity
case-crossover analysis. Environ Health Perspect 113:978–982
Zhang Q, Zhu Y (2012) Characterizing ultrafine particles and other air
pollutants at five schools in South Texas. Indoor Air 22:33–42.
doi:10.1111/j.1600-0668.2011.00738.x
Zhang G, Spickett J, Rumchev K, Lee AH, Stick S (2006) Indoor
environmental quality in a ‘low allergen’ school and three standard
primary schools in Western Australia. Indoor Air 16:74–80
Zhu CS, Cao JJ, Tsai CJ, Shen ZX, Ho KF, Liu SX (2010) The indoor
and outdoor carbonaceous pollution during winter and summer
in rural areas of Shaanxi, China. Aerosol Air Qual Res
10:550–558
Environ Chem Lett
123
Author's personal copy