Topic C6: Low energy buildings
SEMI-VOLATILE AND VOLATILE ORGANIC COMPOUNDS IN LOW-ENERGY
AND CONVENTIONALLY BUILT HOUSES
Samuel HARTIKAINEN1,*, Kari SALMI2, Maija LEPPÄNEN1, Marko HYTTINEN1, Erkki
KÄHKÖNEN2, Rauno HOLOPAINEN2 and Pertti PASANEN1
1
2
*
Department of Environmental Science, University of Eastern Finland, Kuopio, Finland
Finnish Institute of Occupational Health, Helsinki, Finland
Corresponding email: [email protected]
Keywords: SVOC, VOC, Low-energy house, Polyurethane
INTRODUCTION
Energy saving is taken as a target in building codes of many countries demanding increased
insulation of the building envelope. In many cases, the energy saving is also done by
decreasing the air exchange rate. This action may potentially decrease the indoor air quality
(IAQ) in low energy houses, and also reflect to the air quality during the normal living. The
aim of this study was to find out if the IAQ is weakened by semi-volatile organic compounds
(SVOCs) or volatile organic compounds (VOCs) in airtight low energy houses compared to
that in the conventially built reference houses. Various additives are used in manufacture or
for modification of mechanical, chemical, and physical properties of building materials and
consumer goods. Many of these additives are VOCs used as solvents or SVOCs used as
plasticizers and fire retardants in materials. These additives are not bound to the polymer
matrix in plastics and the migration to the surface and release to the environment by abrasion,
dissolution and volatilisation can occur. The concentration of VOCs originated from the
materials tends to decrease within the time, while SVOCs tend to adsorb on the surfaces
because of their lower vapor pressure. Exposure to SVOCs like phthalates and flame
retardants can occur by skin contact, ingestion, or inhalation (Fong et al., 2014, Saito et al.,
2007).
Organophosphate esters (OPs) such as tributyl phosphate (TBP), tris(2-chloroethyl)
phosphate (TCEP), tris(2-chloro-1-methylethyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl)
phosphate (TDCPP), triphenyl phosphate (TPP), tris(2-ethylhexyl) phosphate (TEHP) and
tricresyl phosphate (TCP), are commonly used as plasticizers and flame retardants in
applications were the ignitability and burning rate of the consumer products and building
materials need to be reduced (IPCS 1998 and 1991). The high-molecular-weight phthalates,
such as di-isononyl phthalate (DINP), di-isodecyl phthalate (DIDP) and di-n-octyl phthalate
(DNOP) are widely used as general purpose plasticizers, because of their low cost, high
permanence, versatility and low migration. The low-molecular-weight phthalates, such as
di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP) and benzyl butyl phthalate
(BBP) are tightly regulated by the European Union legislation, because they are recognised as
potential hormone disrupters in animal studies (ECHA, 2013). Dimethyl phthalate (DMP)
and diethyl phthalate (DEP) are used ubiquitously not only as plasticizers but also as solvents
to bind cosmetics and fragrances. Because of their low molecular weight, they are commonly
found in indoor air. Other commercially used phthalate plasticizers are dipropyl phthalate
(DPP), di-isobutyl phthalate (DIBP), dicyclohexyl phthalate (DCHP).
METHODOLOGIES
Eight low-energy houses and six conventionally built buildings were selected for the study.
The low-energy houses were built between the years 2009 and 2011, and the conventionally
built buildings between the years 1956 and 2011. The main thermal insulation material used
in the low energy buildings was polyurethane foam board, while in the conventionally built
buildings the main thermal insulation material was mineral wool. Indoor air samples for
SVOC analyses were collected with SUPELPAK-2SVTM (Supelco, Sigma Aldrich) adsorbent
and glass fibre filter by active sampling in living room and bedroom. Sampling time was 12
hours for each sample. In this study, 16 different SVOCs, namely nine different phthalate
plasticizers DMP, DEP, DPP, DIBP, BBP, DCHP, DEHP, DBP and DNOP, and seven
different organophosphate ester flame retardants TBP, TCEP, TCPP, TDCPP, TPP, TEHP
and TCP, were determined simultaneously from indoor air samples. Samples were extracted
with/by ultrasound and subsequently analysed by GC-MS (GC Agilent 6890, MS Agilent
5973 inert, column Zebron ZB-Semivolatiles 30m x 0.25 mm x 0.25 µm). Deuterated DBP
and deuterated DNOP were used as internal standards for phthalates. Tripropyl phosphate
(TPrP) was used as an internal standard for organophosphate ester flame retardants. External
standards were used to determine the individual retention times of compounds during the GCMS analyses. The detection limit for GC-MS method used in SVOC analyses was 4 ng/m3 for
each compound. Indoor air samples for VOC analyses were collected by Tenax GR adsorbent
by active sampling in living room and bedroom. VOC-samples were analysed by thermo
desorption GC-MS (Markes TD-100, MS Agilent 5975C VL MSD, GC Agilent 7890 A) by
using ISO 16000-6 (2004) standardized method. Detection limit for VOCs was 1 µg/m3 for
every compound.
RESULTS AND DISCUSSION
The concentrations of selected phthalate plasticizer compounds varied between 4 – 1540
ng/m3 (Fig 1.) and the concentrations of selected fire retardant compounds varied between 4 350 ng/m3 (Fig 2.). The total concentrations of volatile organic compounds (TVOCs) were at
the normal level in the low-energy buildings (44 – 560 µg/m3) and in the conventionally built
buildings (60 – 380 µg/m3) compared to the levels in Guidance for Healthy Housing,
Ministry of Social Affairs, Finland (2003).
Figure 1. Concentrations of the phthalates in the living rooms (A) and in the bedrooms (B) of
the conventionally built reference houses (REF1 – REF6) and the low energy houses (LOW1
– LOW9). LOW1 was an unoccupied one-room-flat located to same house with LOW2.
Figure 2. Concentrations of the organophosphate ester fire retardants in the living rooms (A)
and in the bedrooms (B) of the conventionally built reference houses (REF1 – REF6) and the
low energy houses (LOW1 – LOW9). LOW1 was an unoccupied one-room-flat located to
same house with LOW2.
CONCLUSIONS
There was no clear evidence that the IAQ was weakened by SVOCs or VOCs in airtight low
energy houses compared to that in the conventially built reference houses. This study shows
also that there are multiple sources of VOCs and SVOCs in the indoor environment, which
can be seen as a variation in the chemical content of indoor air in different houses. This study
shows also that the concentrations of analysed compounds can variate also between the living
room and the bedroom in the same house.
ACKNOWLEDGEMENT
This study is financed by RYM Ltd, which is partly funded by the Finnish Funding Agency
for Technology and Innovation (Tekes), Halton Ltd and SPU Ltd.
REFERENCES
1. IPCS, International programme on chemical safety (1998) Environmental health criteria
209: Flame retardants: tris (chloropropyl) phosphate and tris (2-chloroethyl) phosphate.
World Health Organization, Geneva.
2. IPCS, International programme on chemical safety (1991) Environmental health criteria
112: tri-n-butyl phosphate. World Health Organization, Geneva.
3. Saito I., Onuki A., Seto H. (2007) Indoor organophosphate and polybrominated flame
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6. ISO 16000-6 (2004) Indoor air – Part 6: Determination of volatile organic compounds in
indoor and test chamber air by active sampling on Tenax TA sorbent, thermal desorption
and gas chromatography using MS/FID.
7. Guidance for Healthy Housing (2003), Ministry of Social Affairs, Finland.