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Atmospheric Environment xxx (2014) 1e7
Contents lists available at ScienceDirect
Atmospheric Environment
journal homepage: www.elsevier.com/locate/atmosenv
Volatile Organic Compounds: Characteristics, distribution and sources
in urban schools
Nitika Mishra a, b, Jennifer Bartsch c, Godwin A. Ayoko a, b, Tunga Salthammer a, c,
Lidia Morawska a, b, *
a
International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD 4001, Australia
b
Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane 4059, Australia
c
Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, D-38108 Braunschweig, Germany
h i g h l i g h t s
VOCs represent a major group of indoor and outdoor air pollutants.
Indoor and outdoor VOCs in 25 primary schools in Brisbane were quantified.
PCA- APCS technique used to identify sources of VOCs and their contributions.
Risks of exposure associated with indoor sources including cleaning products.
a r t i c l e i n f o a b s t r a c t
Article history: Long term exposure to organic pollutants, both inside and outside school buildings may affect children's
Received 7 August 2014 health and influence their learning performance. Since children spend significant amount of time in
Received in revised form school, air quality, especially in classrooms plays a key role in determining the health risks associated
30 September 2014
with exposure at schools. Within this context, the present study investigated the ambient concentrations
Accepted 30 October 2014
Available online xxx
of Volatile Organic Compounds (VOCs) in 25 primary schools in Brisbane with the aim to quantify the
indoor and outdoor VOCs concentrations, identify VOCs sources and their contribution, and based on
these; propose mitigation measures to reduce VOCs exposure in schools. One of the most important
Keywords:
Volatile Organic Compounds
findings is the occurrence of indoor sources, indicated by the I/O ratio >1 in 19 schools. Principal
Ambient concentrations Component Analysis with Varimax rotation was used to identify common sources of VOCs and source
Personal exposure contribution was calculated using an Absolute Principal Component Scores technique. The result showed
Schools that outdoor 47% of VOCs were contributed by petrol vehicle exhaust but the overall cleaning products
Children had the highest contribution of 41% indoors followed by air fresheners and art and craft activities. These
findings point to the need for a range of basic precautions during the selection, use and storage of
cleaning products and materials to reduce the risk from these sources.
© 2014 Elsevier Ltd. All rights reserved.
1. Introduction fumes, cleaning products, heating, varnishing and painting, com-
puters, photocopiers and printers (Destaillats et al., 2008; Jia et al.,
Volatile Organic Compounds (VOCs) are released into the envi- 2008; Wu et al., 2011). Urban air consists of different types of VOCs,
ronment via natural and anthropogenic processes. They represent a many of which are classified as group 1 carcinogen (e.g. benzene),
major group of indoor and outdoor air pollutants; they are ubiq- potential carcinogens (e.g. toluene and xylenes) while some,
uitous and associated with increased long term health risks. including formaldehyde are classified as known carcinogens (IARC,
Vehicular and industrial emissions are the major sources of VOCs in 2006) to humans.
outdoor air, while the indoor sources are tobacco smoke, cooking Children are exposed at schools to pollutants from different
emission sources operating both inside and outside the classroom.
Indoor air quality may even be of more concern in classrooms than
in other types of buildings due to a number of factors, including
* Corresponding author. International Laboratory for Air Quality and Health,
higher occupant density (i.e. volume of classroom and number of
Queensland University of Technology, Brisbane, QLD, 4001, Australia.
E-mail address: [email protected] (L. Morawska). children), activities conducted inside the classrooms and
http://dx.doi.org/10.1016/j.atmosenv.2014.10.052
1352-2310/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Mishra, N., et al., Volatile Organic Compounds: Characteristics, distribution and sources in urban schools,
Atmospheric Environment (2014), http://dx.doi.org/10.1016/j.atmosenv.2014.10.052
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insufficient ventilation, aggravated by the poor construction and/or populated city in Australia, with population more than 2 million
maintenance of many school buildings. VOC concentration tends to (ABS, 2011). Although the city lies on either side of the Brisbane
be lower in the spacious and well ventilated classrooms with a low River, on a low lying flood plain, it is surrounded by hills, some of
occupancy ratio (Pegas et al., 2011b). Accumulation of pollutants is which reach 300 m in height. The major air pollution sources in
possible when doors and windows remain closed for long periods Brisbane include, vehicle emissions, controlled and uncontrolled
of time in order to maintain thermal comfort, especially in winter. biomass burning in the vicinity of the city and a limited number of
In addition to this, children are involved in different types of art and industrial activities, such as a power station, oil refineries, the
craft activities, with the use of glue and paints that may increase the airport, port and a brewery (Morawska et al., 2002). Brisbane has a
level of VOCs in the classroom as reported by Zhang et al. (2006) subtropical climate, with a hot and humid summer (mean tem-
and Pegas et al. (2011b). Besides these, the use of cleaning and perature 25 C) and a dry, moderately warm winter (mean tem-
other consumer products inside the classroom are also possible perature 15 C), with an average diurnal temperature variation
sources of VOCs. If the school is located in an urban environment, around 9e10 C.
the air quality can be affected by many other factors, such as the
amount and type of passing traffic, distance from the road and the 2.2. Study design
location of drop off and pick up areas, together with some meteo-
rological factors, like wind direction and speed. 2.2.1. School selection and location
The pollutants most commonly monitored in elementary school The 25 state schools selected for this study, coded as S01 to S25,
studies are carbon dioxide, carbon monoxide, nitrogen dioxide, were from a range of different suburbs in the Brisbane Metropolitan
particulate matter (PM10, PM2.5) and inorganic components, as well Area. The schools were randomly selected but they need to meet
as biological agents including airborne fungi and bacteria (Meklin several selection criteria, which were: (i) no major pollution sour-
et al., 2002; Godoi et al., 2009; Sohn et al., 2009). There have ces near the schools other than traffic; (ii) not close to any large
been several studies performed worldwide to assess students' infrastructure project, such as a major road, tunnel or building
exposure to indoor particles, but very few aimed at characterizing construction; and (iii) naturally ventilated classrooms used by 8e11
their chemical composition, and those that did mainly focused on year old children. The general characteristics of each school are
elemental content (e.g. Molnar et al., 2007; Stranger et al., 2008; described in the Supplementary Table S1.
Almeida et al., 2011; Oeder et al., 2012).
Due to the long term health risks associated with organic pol- 2.2.2. Sampling period and sites
lutants, there is increased concern about their presence in the air of The field measurements were conducted throughout the year,
schools. A study conducted by (Godwin and Batterman, 2007) in 64 from October 2010 until August 2012, except on school holidays.
classrooms in Michigan, USA reported that benzene, ethylbenzene, There were two sampling sites for VOCs at each school - one out-
toluene, xylene and limonere were the prevalent VOCs. Sofuoglu door and one indoor. The outdoor site was chosen in a central
et al. (2011) measured the concentrations of VOCs in classrooms, location within the school grounds, which was assumed to repre-
kindergartens and outdoor playgrounds of three primary schools in sent the air quality within the school as best as possible. The indoor
Turkey in different seasons and found the concentrations were site was a classroom used by 8e11 year old children. All of the
higher indoors than outdoors. Ten VOCs were identified in the study classrooms were naturally ventilated via doors and windows, with
conducted in three primary schools in Western Australia (Zhang an occasional use of a fan or local air conditioning systems, which
et al., 2006), of which the highest concentration was measured in were not operated during the measurements. Doors and windows
the visual art classroom. Pegas et al., 2011a, Pegas et al., 2012 were usually closed while doing indoor measurements. Children
investigated the pollutant (organic and inorganic) concentrations were involved in different activities inside the classroom, including
inside and outside school buildings and found the important painting, art and craft.
contribution from indoor sources. In general, literature reports
higher VOC concentrations indoors than outdoors. None of the above 2.3. Sample collection and analytical methods
studies investigated on the sources of VOCs and their contributions.
Therefore, the identification and of outdoor and indoor sources of VOCs samples were collected using active sampling procedure
VOCs particularly in school environment is still lacking. by a portable VOC pump. The flow rate was set to 150 mL/min. The
To address this gap in knowledge, the following aims were measurements were taken at the height of 1.5 m from the ground.
established for this study: 1) to conduct comprehensive measure- Stainless steel desorption tubes filled with Tenax TA ((20/35 and
ments of VOCs in indoor and outdoor air of representative number of 60/80 mesh; 300 mg) were used indoors to prevent terpenes and
urban primary schools; 2) to quantify the relationship between in- aldehydes from analytical losses. To avoid artefacts (due to reactive
door and outdoor VOCs concentrations; 3) to identify the VOCs gases like ozone or NOx) tubes were filled with carbotrap (20/40
sources and activities contributing to these sources in urban schools mesh; 300 mg) for outdoor measurements. Air samples were
and 4) to identify the optimal scenarios for reduction of VOCs collected between 7 am and 5 pm, each day (outdoor: 9:00 am,
exposure to children at schools. This study is a part of larger project 9:45am, 1:10 pm, 1:55 pm; indoor: 7:00 am, 7:45 am, 3:00 pm, 3:45
called “The Effect of Ultrafine Particles from Traffic Emissions on pm; volume: 6 L) in each school. Several sampling periods,
Children's Health (UPTECH),” which seeks to determine the effect of including before the start of class, during school and after school
exposure to traffic generated ultrafine particles and organic pollut- hours was chosen. There were no students and teachers inside the
ants in schools. The complete study design is available online (http:// classroom during the indoor measurements. Once the sampling
www.ilaqh.qut.edu.au/Misc/UPTECH%20Home.htm). was completed, the tubes were made air tight using screw caps,
placed in a ziplock plastic bag and sent to Fraunhofer WKI,
2. Experimental section/material and methods Braunschweig, Germany for analysis.
Laboratory analysis of all sorbent tubes was performed via
2.1. Study location thermal desorption/gas chromatography, coupled with mass
spectrometry (TD-GC/MS), according to DIN ISO 16000-6. An Agi-
Brisbane, the capital city of the State of Queensland, is located lent 7890/5975 GC/MS system equipped with a Markes TD 100
along the South-East coast of the state and is the third most thermal desorber was used and the compounds were separated on
Please cite this article in press as: Mishra, N., et al., Volatile Organic Compounds: Characteristics, distribution and sources in urban schools,
Atmospheric Environment (2014), http://dx.doi.org/10.1016/j.atmosenv.2014.10.052
Page 3
N. Mishra et al. / Atmospheric Environment xxx (2014) 1e7 3
an HP-5MS column (60 m 0.25 mm, 0.25 mm). Further details of
the GC/MS system are provided in Supplementary Table S2.
Identification was based on a probability-based matching (PBM)
library search (McLafferty and Turecek, 1993). Mass spectra and
retention data were compared with those of measured reference
substances. All identified compounds were quantified using inter-
nal and external standards against original reference substances.
The calibration was made using external standards (containing
around 200 compounds commonly found in air samples). Stan-
dards were measured every three weeks and on demand,
depending on the sample. For the substances that were not covered
by mixed standards, single standards for external standardisation
were prepared and updated the database. Quantification with
toluene and other compounds similar to analytes was only done if
no reference standard was available. Internal standards were also
continuously used. For the calibration, the linear regression model
was used (Massold et al., 2005). In all cases the limit of detection
was <1 mg m 3.
2.4. Data analysis
The geometric mean and standard deviation of the ambient
concentration of individual VOCs as well as total VOCs for all
Fig. 2. Average VOCs concentration at different locations (Michigan:(Godwin and
samples were calculated using Microsoft Excel 2007. All of the
Batterman, 2007); Minnesota:(Adgate et al., 2004); Malmo:(Willers et al., 1996);
concentration values were blank corrected. The average total VOCs Turkey: (Sofuoglu et al., 2011); Korea: (Yang et al., 2009); Sweden:(Smedje et al., 1997).
were plotted in a bar diagram against each sampling site, in order to
compare indoor and outdoor concentrations (Fig 2). The I/O ratio
for each sampling site was used in further analysis, in order to 3. Results and discussion
determine the VOCs sources. Traffic density was calculated using
five minute averaging intervals. Average traffic count per hour was 3.1. Meteorological conditions
calculated in all sites for sampling period.
Principal Component Analysis (PCA) with Varimax rotation was The average temperature and relative humidity for each school
applied to the VOC concentration data to identify the VOC sources. during the measurement period (i.e. from 7 am to 5 pm over 4 days
Absolute Principal Component Score (APCS) technique was used to of sampling) are included in Table S3. Sampling at 11 schools was
quantify the source contribution. The detailed description of PCA- completed during the summer (November to April), with an
APCS method was followed as given by (Guo et al., 2004). IBM average temperature of 24 C, while Sampling at 14 schools was
SPSS (version 21) was used for the PCA eAPCS analysis. Before done in winter (May to October), with an average temperature of
applying PCA to the VOC data, individual samples were inspected 16e18 C. Since Brisbane has a subtropical climate, there was a
for their percentage of occurrence in all schools. VOCs with 20% or relatively small difference in summer and winter temperatures. The
less detection rates in the samples were not included in the analysis average humidity varied from 30 to 71%. The wind direction data
and absolute coefficients less than 0.50 have been omitted from the were used to prepare wind rose plots for the entire sampling period
Tables to facilitate source identification. The missing values and at each school to identify the prominent wind direction either from
values below the detection limit were replaced by the geometric school to road or road to school.
mean and half of method detection limit, respectively.
3.2. Composition of air samples
More than 70 VOCs including very few Very Volatile Organic
Compounds (VVOC) and Semi volatile organic compounds (SVOC)
were identified in the air samples collected at the 25 schools. Those
compounds were separated into different groups according to their
chemical structure namely aliphatic hydrocarbons, aromatic hy-
drocarbons, aldehyde and ketones, terpenes, cyclo-aliphatics, al-
cohols, halogenated hydrocarbons, organic acid and esters. The
detailed composition of compounds within each group is provided
in Supplementary Table S4. Overall, more VOCs were identified in
indoor than outdoor air samples.
3.3. Ambient concentration of total VOCs and I/O ratios
This section presents the indoor and outdoor concentrations of
total VOCs (sum of all the quantified VOCs ranging from C6eC16), as
well as I/O ratios and comparison with other studies. In general, the
total indoor VOCs concentrations were found to be higher than
Fig. 1. Total VOCs (geometric mean, mg/m3) for each school. Error bar represents the outdoor concentration, with only five schools having higher out-
std. deviation. door concentrations as can be seen in Fig. 1. The geometric mean
Please cite this article in press as: Mishra, N., et al., Volatile Organic Compounds: Characteristics, distribution and sources in urban schools,
Atmospheric Environment (2014), http://dx.doi.org/10.1016/j.atmosenv.2014.10.052
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4 N. Mishra et al. / Atmospheric Environment xxx (2014) 1e7
or close to one indicates significant outdoor source contribution
(Edwards et al., 2001). The geometric mean concentration of total
VOCs was used to calculate I/O ratios, which were found to be >1 in
the majority (i.e. 19) of the schools studied as can be seen in Fig. 3,
which implies that, in addition to outdoor sources, there were
dominant indoor sources in these schools.
Only five schools (S02, S05, S08, S18 and S19) had I/O ratios <1,
which shows that outdoor VOC concentrations were higher than
indoor, and implying that outdoor sources had dominant contri-
bution. This can be explained by the combination of the important
factors: wind and traffic during school hour as well as the level of
indoor emissions. In S02, S05 and S08 the wind direction was
predominantly from the road to school and the number of vehicles
passing per hour was also higher i.e. 1418, 1096 and 1106, respec-
tively; this accounted for the high outdoor concentrations. S19 had
comparatively high traffic count (1609) though the wind direction
was from the school to the road whereas S18 had very low traffic
count (92 vehicles/hr) and the wind direction was also from the
Fig. 3. Indoor/outdoor ratio (in increasing order) of total VOCs for each school. school to the road. These two factors cannot explain the low value
of I/O ratio in these schools.
It can also be seen from Fig. 4 that I/O ratio in seven schools (S16,
concentrations for indoor and outdoor total VOCs for all schools S23, S09, S17, S13, S12 and S11) was very high indicating dominant
were 125 mg/m3 and 71 mg/m3 respectively. The range for total VOCs indoor sources. There were evidences found inside the classroom
was (8e1070 mg/m3) indoors and (3e826 mg/m3) outdoors. In during the measurements in these schools such as in S09 classroom
addition to this, individual concentrations of the most common was newly painted because the school was flooded, some renova-
compounds and their I/O ratios are presented in boxplots in tion was done recently in S11. Similarly, there were much paper-
Supplementary Figure S5. work activities done by the students hanging on the wall, windows,
Fig. 2 presents a comparison between the total VOCs concen- over desk and benches in S12 and S13. There was a sink inside the
trations identified in this study and those reported in literature. It classroom in S17 where the use cleaning liquids, soaps was very
can be seen that the total VOC concentrations measured in this common. During the measurements in S16 and S23, cleaners were
study were either similar or higher than the studies performed in wiping desk, table using the spray. These local evidences support
other countries, but significantly lower indoors than those for the high concentration indoors in these schools.
measured in South Korea. In the later study the samples were
collected from schools that had been recently renovated and 3.4. Source identification
reconstructed.
In addition to the studies included in Fig. 3, Pegas et al. (2011a), Source identification of indoor and outdoor VOC concentrations
(2011b) reported the range for total VOCs (mg/m3) in different was carried out using the PCA method.
seasons in schools as (a) Indoor: 37e317 in Spring, 11e922 in
autumn, 84e2175 in winter (b) outdoor: 6e18 in spring, 5e50 in 3.4.1. Outdoor VOCs
autumn, 7e22 in winter. Similarly, Sofuoglu et al., 2011 showed the As explained in the data analysis section, out of the 48 outdoor
comparison between outdoor playground and classrooms concen- VOCs identified, the 16 species which were the most abundant
trations in their study (Classroom: 27 in fall, 111 in winter, 66 in compounds in the atmosphere were selected for further analysis.
spring; Outdoor playground: 22 in fall, 41 in winter, 24 in spring). The PCA anysis was carried out twice for outdoor data in order to
Although, season was not taken into consideration in our study, the see the changes made by including and excluding S03 but the re-
overall trend was similar to other studies showing that in all sea- sults were very similar therefore the results with S03 were
sons indoor levels were higher than outdoor. mentioned here. Five components/factors were extracted from the
The I/O ratio is generally used to infer penetration of pollutants application of PCA to the data. The rotated component matrix for
into the indoor environment through doors and windows as well as outdoor VOCs is presented in Table 1. Varimax rotation with Kaiser
the presence of indoor sources (Tang et al., 2005). A ratio less than Normalisation was applied to determine the appropriate number of
Fig. 4. Source contribution of each source to the total VOCs concentrations indoor and outdoor.
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Atmospheric Environment (2014), http://dx.doi.org/10.1016/j.atmosenv.2014.10.052
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N. Mishra et al. / Atmospheric Environment xxx (2014) 1e7 5
Table 1
PCA Analysis of outdoor VOCs.
Factor Sources Major compounds Comments/references
1 Petrol Vehicle Exhaust 2- methyl hexane, 3-methyl hexane, (Liu et al., 2008a), (Han and Naeher, 2006) reported similar compounds
methylcyclohexane, heptanes, from petrol vehicle exhaust.
2- methyl butane, toluene
2 Fuel evaporation 2- methyl pentane, 3- methyl (Geng et al., 2010) suggested that these alkanes are also emitted from
(petrol and diesel) pentane, hexane, pentane fuel evaporation (petrol, LPG/NG and diesel). (Morikawa et al., 1998)
reported pentane as a tracer of petrol evaporation.
3 Industrial sources xylenes(m,-p-,xylene),benzene (Liu et al., 2008b), (Guo et al., 2004) reported similar results in their research.
benzaldehyde
4 Solvent usage o-xylene (Guo et al., 2004) found that o- xylene is one of the constituents of paints and
have also been associated with solvent use.
5 Photochemical process Acetone (Atkinson, 2000; Vlasenko et al., 2009) mentioned that acetone is released as a
secondary product and has a long residence time in atmosphere.
factors to be retained (i.e. only factors with an eigenvalue >1) from the application of PCA to the indoor data (Table S8). Again,
(Kaiser, 1958). Marker compounds for specific sources were deter- Kaiser's criteria were adopted to identify the appropriate number of
mined based on published chemical composition profiles (Vega- factors to be retained (with only factors having eigenvalues >1
Baudrit et al., 2007; Shinohara et al., 2009; Kim et al., 2010; retained) (Kaiser, 1958). Altogether seven factors, representing
Yrieix et al., 2010; Yuan et al., 2010) as well as some prior knowl- seven different source categories, were identified, namely: 1. Out-
edge regarding the sources of VOC species. The five components in door traffic emissions; 2. Off-gassing of building materials and
Table S6 of Supplementary Information represent the following stationaries; 3. Decorating materials and computers, printers; 4.
source categories: 1. Petrol vehicle exhaust; 2. Fuel evaporation Personal care products; 5. Art and craft activities; 6. air fresheners;
(petrol and diesel); 3. Industrial sources; 4. Solvent usage; and 5. and 7. Cleaning products. All of these factors explained 88% of total
Photochemical process. Altogether, 84% of data variability was data variance.
explained by these five factors. The characteristics of the seven source categories obtained from
The characteristics of the five factors representing the five the indoor dataset are summarized in Table 2.
source categories for the data are summarized in Table 2. The source contribution from each factor is mentioned in the
The contribution from each of the outdoor sources are described following section while the detailed description of these indoor
in section 3.4 while the detailed descripton of each factors are sources is included in S9 of the Supplementary information.
included in S7 of supplementary information. The main purpose of the PCA was to reduce the number of inter-
related variables in the original data to fewer number of factors,
3.4.2. Indoor VOCs which are orthogonal to each other. The first factor accounts for the
PCA was applied to indoor VOC data in the same way as the highest variability in the data and subsequent factors account for
outdoor data. Twenty two out of the 60 measured VOCs were progressively less amount of data variance. As it is a qualitative
selected for the PCA analysis. Seven components were extracted analysis, it provides the variance and pattern in the data set but the
Table 2
PCA analysis of indoor VOCs.
Factor Sources Major compounds Comments/References
1 Outdoor Traffic Emissions 2- methyl butane, 2- methyl pentane, The outdoor concentrations of these
3- methyl pentane, hexane, compounds were much higher than
3- methyl hexane, heptanes, toluene indoor and the I/O ratio for these
compounds varied from 0.1 to 0.5,
so they could have penetrated inside
from outdoor air.
2 Off- gassing of building materials and stationaries a- pinene, benzaldehyde, m-, p-,o-xylene, (Weisel et al., 2005)
reported the emission of a- pinene from
plywood. DSEWPC, 2001 mentioned xylenes
as a major solvent in pens/inks and coatings
3 Decorating materials and computers, printers 2-ethyl 1-hexanol, phenol,n-nonanal, Edwards et al., 2001) reported a similar
styrene result in their study of VOCs in Finland.
(Kagi et al., 2007) reported that styrene
is produced indoor air from printers,
computers
4 Personal care products Acetone, siloxane (Bernstein et al., 2008) reported that
siloxanes are widely used in personal
care products. Acetone is also used as
one of the ingredients in such products.
5 Art and craft activities Acetic acid (Colak and Colakoglu, 2004) found that
wood based materials elevated the level
of acetic acid.
6 Air fresheners Decanal (Pluschke, 2004; Fukuda et al., 2010)
reported decanal as one of the compounds
in air fresheners.
7 Cleaning products Limonene (Nazaroff and Weschler, 2004) reported
limonene as an active ingredient in cleaning
products.
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6 N. Mishra et al. / Atmospheric Environment xxx (2014) 1e7
results of it cannot be used directly for source contribution. For e.g. (iii) What measures can be taken with respect to the traffic
29% of the data variance was explained by the first factor i.e. out- impact?
door traffic emissions in indoor VOC, but that doesn't mean that it
will have a comparable contribution to the indoor VOC concen- The outdoor traffic was found to have very negligible contri-
tration. High variance was due to the big differences in the con- bution (2%) in indoor VOCs concentrations but the contribution of
centration values of the VOCs associated with factor 1. 70% on outdoor was from traffic related sources, so providing drop
Therefore, the results of PCA were subjected to a receptor off/pick up area as far as possible from buildings and stopping the
modelling approach Absolute Principal Component Scores (APCS) engine of the vehicles while waiting can improve the situation
that is based on multiple linear regressions which gives the quan- outdoors. This is of importance, considering that children do spend
titative estimates of source contributions and profiles associated a lot of time on outdoor school activities. When they are active, the
with each factor by calculating absolute principal component inhalation rate increases and thus pollutant intakes.
scores and then regressing the total VOCs concentrations on these
scores (Thurston and Spengler, 1985). Acknowledgements
3.5. Source contribution This work was supported by the Australian Research Council
(ARC), Department of Transport and Main Roads (DTMR) and
The mass contribution of each source to the total ambient VOCs Department of Education, Training and Employment (DETE)
concentration in indoor and outdoor air was estimated as shown in through Linkage Grant LP0990134. Our particular thanks go to R.
Fig. 4. It was found that 41% of indoor VOCs concentrations in Fletcher (DTMR) and B. Robertson (DETE) for their vision regarding
schools were attributed to the cleaning products followed by air the importance of this work. We would also like to thank all
fresheners (23%) and art and craft activities (21%) while the rest members of the UPTECH project, including Prof G. Marks, Dr P.
were caused by personal care products (5%), (most likely sunscreen, Robinson, Prof K. Mengersen, Prof Z. Ristovski, Dr M. Mazaheri, Dr C.
body powder/lotion, shampoo, hair oil), decorating materials and He, Dr G. Johnson, Dr R. Jayaratne, Dr S. Low Choy, Prof G. Williams,
computers, printers (5%), offgasing of building materials and sta- W. Ezz, F. Salimi, L. Crilley, S. Clifford, M. Mokhtar, R. Laiman, L. Guo,
tioneries (3%) and outdoor traffic emissions (2%). The highest Prof C. Duchaine, Dr H. Salonen, Dr X. Ling, Dr J. Davies, Dr L.
contribution of cleaning products and air fresheners was likely due Leontjew Toms, F. Fuoco, Dr A. Cortes, Dr B. Toelle, A. Quinones and
to the fact cleaning of the classrooms and materials inside is the P. Kidd for their contribution to this work. We thank former ILAQH,
important and regular (twice a day) activity in schools that aims to QUT members Dr M. Falk, Dr F. Fatokun, Dr J. Mejia and Dr D. Keogh
promote hygiene and preserving materials. The level of limonene for their contributions at the early stage of the project. Thanks also
was found below the reference value of 450 mg/m3 (JRC, 2005) for to R. Appleby and C. Labbe for their administrative assistance and
schools, therefore the cleaning products themselves are not ex- Dr. Adrian Friend for his support for APCS analysis.
pected to be a significant health risk. However, secondary organic
aerosols may be formed by the reaction of limonene, with the
Appendix A. Supplementary data
hazard they create unknown.
About 70% of outdoor VOCs concentrations were attributed to
Supplementary data related to this article can be found at http://
traffic i.e petrol vehicle exhaust and fuel evaporation. Other sources
dx.doi.org/10.1016/j.atmosenv.2014.10.052.
such as industrial source, solvent usage and photochemical process
contributed 26%, <1% and 3% respectively. (Guo et al., 2004) also
found the highest contribution from vehicle emissions and gasoline References
evaporation in their studies.
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Please cite this article in press as: Mishra, N., et al., Volatile Organic Compounds: Characteristics, distribution and sources in urban schools,
Atmospheric Environment (2014), http://dx.doi.org/10.1016/j.atmosenv.2014.10.052