Download SOHIE, A European Data Base on Indoor Air Pollution Sources

SOPHIE, A European Database on Indoor Air Pollution
Sources
Paper # 1039
Eduardo de Oliveira Fernandes1, Philomena M. Bluyssen2, J.L.Molina3
1
FEUP, Universidade do Porto, 4200-465 Porto, Portugal; 2TNO, P.O. Box 49, NL-2600 AA
Delft, The Netherlands; 3AICIA, University of Sevilla, 41092 Sevilla, Spain.
ABSTRACT
The Indoor Air Quality issue is mostly centered around a triangle of topics: health and
comfort effects, pollution sources and ventilation. Strategies for good IAQ include giving
priority to source control since ventilation techniques have proven not to respond properly in
every circumstance. Ventilation systems are themselves often a cause of indoor pollution, and
ventilation levels are also being subject to constrains imposed by energy efficiency targets in
buildings.
In the context of the European Union RTD Programme, some projects were launched since
1991 aiming at identifying the main causes for the indoor pollution and defining and
preparing a tool of some universal character to enable industry and professionals to allow to
relate the strength of the pollution sources with the IAQ conditions. SOPHIE is a database
containing information on hundreds of materials as pollution sources and chemical substances
as pollutants, and, a model allowing to integrate the information of the strength of the sources
to calculate the ventilation rate that assures a proper level of IAQ.
This paper presents the main features of SOPHIE and the conditions under which the data
were obtained, namely the agreed protocols adopted by a number of prominent laboratories in
Europe. A special focus will be made on the way SOPHIE can be used to provide information
for designing buildings for better IAQ but, probably more important, as a reference database
for the enhancement of the cleanliness and sustainable character of materials and other
building products towards the future.
INTRODUCTION
Indoor Air Quality (IAQ) is becoming more and more a key issue in today’s health policies.
As personal air exposure becomes more dependent on the indoor environment, where people
can spend more than 90 % of their life time, IAQ needs to be tackled together with and in a
necessary continum to the more common ambient air quality approaches.
IAQ is mostly centered around a triangle of topics: health and comfort effects, pollution
sources and ventilation. It is difficult to deal with health effects at indoor levels, as
epidemiological studies are, in general, a very complex task and because concentrations of
pollutants in indoor air are usually very low. The most common types of effects can be
identified as being: sick building syndrom, building related illnesses such as allergies and
asthma, and cancer. Yet, there is a lack of a foundation for the definition of what is acceptable
IAQ from the health point of view as no generally accepted procedure for evaluation of the
effects of the multiple low level exposures is agreed [1].
There are three commonly presented strategies to promote good IAQ: (a) source control,
meaning that sources of indoor pollutants shall be avoided or confined or their strength be
minimized; (b) dilution, in tune with the fact that exposure will be less if, for the same time
duration, the concentrations of the pollutants in the air are lower; and (c) the removal,
basically through filtration and ventilation techniques which have proven not to respond
properly in every circumstance.
Despite all progress in filtration technology, still many questions remain about the
performance of filters. One area of performance in question includes what could be called the
secondary pollutants eventually generated in the filter matrix itself, such as odours [2]. In the
past, ventilation has been presented as the panacee for good IAQ. Yet the so-called fresh air
must come from a clean outdoor area. Furthermore, it has been already abondantly illustrated
that ventilation systems can themselves be causes for non negligeable indoor air pollution [3].
However, the fact that the criteria to establish the ventilation rates adequate to each situation
have been missing and that other types of constraints emerged, namely the trends to reduce
the energy consumption, led to a lot of changes in recommended ventilation rates in the last
150 years.
Recent studies have shown that to guarantee good IAQ for comfortable and healthy indoor
environments in the future, more detailed efforts must be made giving priority to the source
control approach [2]. The concept of sustainability will also encourage that materials and
energy used in buildings converge to the same ultimate objective: to make healthier and more
environmental friendly buildings (i.e., buildings contributing to a better environment both
indoors and outdoors) [4].
In the context of the European Union RTD Programme, a few projects were launched since
1991 [2,3,5,6] aiming at identifying the main causes of indoor air pollution and defining a
database as a tool of some universal character to enable industry and professionals to relate
the pollution sources with the IAQ conditions through the ventilation rates. The expected final
result would have been a set of protocols and of formats to collect, store and manipulate data
that could be recognised by growing shares of the technical and professional communities.
Some of those protocols were tested in parallel with the development of guidelines and
standards in several fora [7,8,9,10].
The most relevant products of the whole ten year programme would be a database containing
information on hundreds of materials as pollution sources and a model allowing to integrate
the information on the strength of the sources and to calculate the ventilation level that assures
proper IAQ.
This paper presents the database SOPHIE and some of its main features. A special focus is
made on the way this database can be used to provide information to designers for developing
buildings with better IAQ and, more importantly, on its potential as a reference database for
the enhancement of the cleanliness and sustainable character of materials and other building
products towards the future.
SOPHIE – SOURCES OF POLLUTION FOR A HEALTHY AND
COMFORTABLE INDOOR ENVIRONMENT
SOPHIE is the acronym adopted for a database of indoor air pollution sources, including
building materials and furnishings and ventilation system components. It represents the result
of the work of a vast network of laboratories in Europe developed under the sponsorship of
the European Commission. It aims to document the most important indoor pollution sources
and to create a model to establish the link between the strength of the pollution sources and
the ventilation rate and its consequences in terms of IAQ in a given space.
SOPHIE is a tool that can become a reference database and function as a basis for the
launching of more practical or specific databases and labelling frameworks at different levels.
This could be by differentiating construction products or by reflecting the diversity of state or
national contexts. Its data can be handled and compared with a particular high degree of
confidence as its results have been obtained from different laboratories following the same
protocols and checked through different processes (i.e. pilot studies of inter-calibration at the
European level) [11]. The structure of SOPHIE is illustrated in Figure 1.
Figure 1: SOPHIE Structure
Modelling of Ventilated Spaces
Building Materials
Protocol for Characterisation of Indoor Air
Pollution Sources
Coupling
Diffusion
Pre-existing model for
dynamic thermal behaviour of
buildings
Sorption and Air movement
Testing in Chambers
Chemical emission
Toxicological
Information
Sensory
evaluation
Model
Database on Indoor Air
Pollution Sources
Toxicological
evaluation
Informative Data
Userfriendly Programme SOPHIE
It contains information on some HVAC-components but the more prevalent information
refers to construction materials. Table 1 makes a balance of the type of materials tested and of
how many tests were performed during the two major campaigns of the development process
of SOPHIE. Those materials have been tested according to standard procedures for testing
chambers [9] and for chemical analysis [10]. A sensory assessment was also performed [12].
Two product ages were generally considered for the materials tested: 3 and 30 days. In some
cases an intermediate age of 14 days was also considered.
SOPHIE is more than just a static list of materials organised by several different criteria
related to their contribution to the indoor air quality. Once the emission rate of chemicals by
the different materials was determined, the next step was to establish the model to link the
concentrations of those chemical substances (pollutants) in a given space with a certain level
of ventilation rate and with the dynamics of a certain thermal environment indoors. That is
why a major tool is incorporated to enable the linkage of the ventilation conditions with the
actual level of the IAQ conditions for a certain type of occupation, including the nature and
the extension of materials employed. It is a dynamic model quite ambitious but probably with
the merit of establishing a frame with enough generality and broadness to allow for further
developments.
The model has certainly many limitations, some related to the status of the current knowledge
and others due to the lack of appropriate information. It is clear nowadays that
sorption/desorption effects play an important role on the actual levels of the concentrations of
certain pollutants depending on the different ambient conditions, but, above all, on the
interaction of the material/substance. The fact is that the values for specific coefficients of
adsorption or desorption of a particular chemical substance in a given material are generally
unknown. Recent studies have been made in order to obtain the information needed on the
sorption/desorption coefficients for different coupling material/substance. [13] So far, that
work has only been done for a very limited number of cases. Given the hundreds of
substances and materials that can be present, that limitation represents probably the major
bottleneck to the wide application of the model.
Table 1. Description of emission sources and related tests investigated for SOPHIE.
Type of Source
Number
of sources
FLOORING
56
WALL
33
CEILING
2
CONSTRUCTION
14
OTHER
14
HVAC-Components.#
16
1994 – 1997
1998 – 2000
#
Number of Chemical Tests
Number of Sensory Tests
3rd day
14th day
30th day
3rd day
14th day
30th day
53
26
2
10
13
18
14
5
0
3
2
0
55
29
2
14
14
0
57
14
0
17
11
39
28
0
0
8
6
0
57
14
0
17
11
0
86
46
24
0
68
46
106
32
32
10
67
32
85
50
Tests not related to time but air volume
It is well known that there are many pollutants which cannot be traced chemically. That often
makes sensory evaluation absolutely necessary. Unfortunatelly, there has been some
controversy regarding the meaning of the different procedures for sensory assessment [12], in
particular, on the way through which the relationship between the sensory information and the
ventilation rate can be established. That controversy became more apparent in Europe in the
late 90’s to the point that it influenced the development of SOPHIE negatively. Since the
scientific community has not been been able to reach the necessary clarification on this matter
so far, the sensory information, as well as the information on the toxicity of some selected
substances, will be part of the database but cannot be worked out through the model. This data
will be available only on an informative basis.
DATA FROM TESTING
A database can only be of interest if the quality of the data is assured, in particular, in regard
to their relative coherence and consistency. Therefore, the experimental work to be performed
by independent and reliable laboratories has to be conducted using the same procedures. The
procedures adopted under a former agreement among participating laboratories were the same
as already existed in the European standards for chamber operation, sampling and test
specimen preparation [9]. It has to be recognised that there was some simultaneous work
between the development of SOPHIE and the standardisation process. Therefore, SOPHIE
can emerge as a precursor having a patrimony of experience and gathering a set of data that
would not be possible to have today, if the approval of the standard was to precede the tests.
In this context, the agreement among several laboratories in different countries, obtained
previously to the test campaigns, was a key element for SOPHIE and represented a good
background for the development of the work in the standardisation process.
The method for determination of VOCs is defined on the standard ISO DIS 16000-6 [10]. It
defines that the VOC emissions shall be quantified by their own response factors. This is in
contrast to the major part of the internationally available data where quantification has been
done as toluene equivalent.
MODEL
The dynamical modelling of the effect of ventilation strategies on indoor air quality of
buildings had as its main objective to obtain a model able to evaluate the indoor air quality in
a particular zone of a building in terms of levels of concentrations of pollutants. The
modelling exercise was completed taking into account the effect of possible different
ventilation strategies and thermal dynamics of the building as well as the effects of sorption
and desorption of chemical compounds in building materials [13].
The effect of ventilation strategies can not be calculated without considering the thermal
dynamics of the building, which is very important for comfort and health purposes even if no
attention is paid to IAQ. The effects of sorption and desorption can not be evaluated without
the knowledge of the temperature of the indoor air and those of the different materials. So, an
important piece in this method is the dynamical thermal model of the building in which the
specific IAQ model has been introduced.
The sequence of the work was as follows: non steady state diffusion model of mass and heat
transfer through building materials; sorption (and desorption) model of the diffusion of
pollutants (mass) through the building materials; and model of the air movement including
both the natural air movement and the forced air movement simulated by the behaviour in
jets. Coupling all the previous phenomena a new model was created, representing a tool for
calculating the dynamical thermal behaviour of buildings. Then the model was introduced in
the database and software was produced for including the results of tests and presenting the
SOPHIE outputs.
POTENTIAL FOR BETTER INDOOR AIR
There is nowadays a clear trend towards the production of cleaner materials for buildings. The
reasons are obvious from the point of view of the environment in general but also from the
perspective of the indoor air or the quality of the indoor environment. The quality of the
indoor air is linked to the quality of the ambient air because supply air tends to be taken from
outside – recirculation has become less recommended – and ventilation is an important energy
demanding service. In OECD countries the top energy consumer is the building sector
accounting for about 40% of the total energy used. In a recent document issued by the
European Commission (Green Paper) [14] it is clearly assumed that the strategies for CO2
economy cannot be successful if the control of the diffuse consumers such as transportation
and buildings is not assured. In regards to buildings, ventilation is definitely one of the major
causes of energy consumption. More ventilation is, in principle, beneficial for a better IAQ
and less ventilation is beneficial for less energy used and consequently for better outdoor air.
Therefore, the aim shall be to obtain a solution that creates the conditions, by a wise source
control methodology, to have no more than just the right amount of ventilation necessary to
assure that the absolute needs for good IAQ are guaranteed.
EXAMPLE
Let us consider a room in an office building, located in Seville (Spain). The office has 9 m 2 of
floor area, 3 m height with a window (2.12.1 m2) in the south façade. Internal gains of 30
W/m2 (sensible) are considered. The floor is covered with a carpet which emits 46 g/h/m2 of
formaldehyde (among other pollutants, see table 2).
Table 2: Emission rates (g/h/m2) from floor material
The ventilation fans are on during the working period (7-15 hours) assuring 2 air changes per
hour. In the base case 0.5 renovations are of outdoor clean air. Qualitative results for
formaldehyde concentrations in the vertical central plane cells of the room are shown in
figure 2. When the fans are off there is only natural movement of the air (Fig. 2a) . There is a
clear stratification of the concentrations near the floor, partly broken by the movement of air
due to the free convection near the window. When the fans are on, with the return vent located
near the ceiling, the cell shapes change to accommodate the jet trajectory. It can be seen how
the stratification changed being apparent some higher concentrations in the cells just below
the supply vent.
Results regarding the impact on energy use can also be obtained. Figure 3 shows the energy
demands for heating and cooling, for the base case (a) and when the outdoor air supply
increases from 0.5 to 1.5 air changes per hour (b). The heating demand increases from
823 kWh to 1000 kWh, whereas the cooling demand increases from 320 to 446 kWh. On the
other hand, maximum formaldehyde concentration is reduced from 0.0026 ppm to
0.0013 ppm. Making some energy recovery via heat exchangers or free cooling can reduce the
increment on the energy demand due to higher ventilation rates. On figure 3 (c) the results of
incorporating free cooling controlled by temperature are shown. The heating demand is
reduced to 810 kWh and the cooling demand goes down to 294 kWh.
a
b
Figure 2. Qualitative results for formaldehyde concentrations: a) – no ventilation; b)
ventilation with jet on the wall
Heating
Base Case: 2 ach + Free Cooling, T
Base Case: 2 ach (1.5 O.A.)
Base Case: 2 ach (0.5 O.A.)
Heating
Cooling
Heating
Cooling
150
100
100
100
50
50
50
0
0
11
200
150
9
200
150
7
200
5
250
3
250
1
250
Cooling
0
1
2
3
4
5
6
7
8
9 10 11 12
1
2
3
4
5
6
7
8
9 10 11 12
a
b
c
Figure 3. Heating and cooling demands for base case (a), higher percentage of outdoor air (b)
and free cooling (c)
HOW TO USE SOPHIE
The question of how access to SOPHIE is achieved has been raised for a few years now. A
marketing plan was created, a questionnaire to different industry representatives was
promoted and several options are being considered to launch a process of making SOPHIE
available in a dynamic and interactive way. Every time the concept has been presented and
further steps in the development of this database have been shown, more interest was
generated.
From these marketing and promotion activities around SOPHIE, quite a bit of interest in
SOPHIE has been generated not only from the industry and research community in Europe,
but also from USA, Japan, and Australia [13]. Most of the interested parties accept all the
current available features. However, many would prefer to add some features such as
commercial names of products, access to complementary info on products, a
classification/labelling system and a link to other databases. English is not a problem. Most
are interested in becoming a member of an organisation around SOPHIE.
The problem is that SOPHIE is not specific and asks for a sound engagement of a few entities
to make sure that it can keep developing in the future and does not loose its momentum.
Among the alternative ways of accomplishing this is through the creation of a club of users
through which the adoption of the concepts and practices become tested and eventually
enhanced exploring a tool of interaction among manufacturers, designers users and regulators.
This possibility could be reached in the very near future through a “thematic network”, a
specific European RTD action for information and dissemination. In this process, to be
launched in the next months, the interest of laboratories with experience on testing materials,
labelling and certification will be essential.
Nowadays there is a great interest for materials labelling. Several labelling schemes are
available at the national level. SOPHIE may not be directly useful to such an activity but it
could help the labelling process, in particular if a European (or even global) labelling system
would to be implemented. The fact that SOPHIE can rank an expressive number of materials
and chemical substances it can act as a reference or background database. Every time a new
product is tested and recognised as being a clean or a low polluting material according to the
current criteria, it can be introduced into the database. This way, SOPHIE can be kept updated
in terms of new products and of cleaner products assuming that cleaner raw materials and
components are used more and more in a continuous emulation process towards a more
sustainable world.
CONCLUSIONS
There is a need to enhance the access to methods and protocols in order to widen the assessed
information and to create the opportunities and means for management of indoor air pollution
sources in order to give credibility to the information used when documenting their
performance.
IDMEC
SOPHIE is certainly one of those tools that may contribute towards a more systematic and
universal approach to the IAQ issues beyond the interests of groups, be it of manufacturers or
other professionals.
Besides other potential uses, there seems to be a special “niche” of market for SOPHIE as a
reference database, closer to laboratories and institutions where the data is obtained and the
products are certified.
SOPHIE can be a strong element as a reference tool in the process for labelling materials in a
coherent sound trans-national context.
In Europe, actions are on the way to make certain SOPHIE is enhanced and exploited in such
a way that it contributes to the creation of healthy and energy efficient buildings.
Contributions and opportunities for interaction with other Nations are nevertheless very much
appreciated.
AKNOWLEDGMENTS
SOPHIE was sponsored partly by the European Union in the JOULE programme (DGXII)
and involved several laboratories from different countries namely: FEUP - Faculdade de
Engenharia da Universidade do Porto, Portugal, acting as co-ordinator. Other participants
were: Technical University of Denmark, Department of Energy Engineering, Denmark; TNO
Bouw, Division Building and Systems, Netherlands; VTT Chemical Technology – Technical
Research, Finland; CSTB – Centre Scientifique et Technique du Bâtiment, France; AICIA –
Asociacion de Investigacion y Cooperacion Industrial de Andalucia, Spain; and FriedrichSchiller - University Jena, Erfurt, Germany.
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