GUIDANCE ON PRODUCT EMISSIONS BY LABORATORY TESTING

THE EPHECT EXPERIENCE

John Bartzis, Evangelos Tolis, George Efthimiou (UOWM)

Peder Wolkoff (NRCWE)

Marianne Stranger, Frederick Maes, Eddy Goelen (VITO)

Gabriela Ventura, Eduardo de Oliveira Fernandes (IDMEC)

September 2013

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DISTRIBUTION LIST

Vlaamse Instelling voor Technologisch Onderzoek , Mol, Belgium

University of Western Macedonia Research Committee, Kozani, Greece

Agence Nationale de Sécurité Sanitaire, Alimentation, Environnement, Travail, Paris, France

Technische Universität München, Germany

National Research Centre for the Working Environment, Copenhagen, Denmark

Instituto de Engenharia Mecanica Environment, Porto, Portugal

Universita Degli Studi di Milano, Italy

Ipsos Belgium, Waterloo, Belgium

“©UOWM, VITO, NRCWE, IDMEC All rights on the materials described in this document rest with UOWM, VITO, NRCWE, and IDMEC. This document is produced in the frame of the EPHECT –project. The EPHECT-project is co-funded by the European Union in the framework of the health Programmes 2006-2013. The information and views set out in this document are those of the author(s) and do not necessarily reflect the official opinion of the European Union. Neither the European Union institutions and bodies nor any person acting on their behalf, nor the authors may be held responsible for the use which may be made of the information contained herein. Reproduction is authorized provided the source is acknowledged.

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TABLE OF CONTENTS

Distribution List ________________________________________________ II

Table of contents _______________________________________________ III

List of figures __________________________________________________ IV

List of tables ___________________________________________________ V

Nomenclature _________________________________________________ VI

Chapter 1: Introduction ___________________________________________ 8

Chapter 2: Consumer product testing________________________________ 9

2.1 Background 9

2.2 Pollutant Mass transfer mechanisms 10

2.3 Parameters that influence the mass transfer 12

2.4 Selection of test chamber 13

2.4.1. Additional considerations 14

2.5 The preparation phase for testing 15

2.5.1 Start-up conditions 15

2.5.2 Initial test conditions 16

2.5.3 Product specific test chamber conditions 16

Liquid consumer and personal care products 17

Solid consumer and personal care products 20

2.6 Testing and Sampling phase 21

2.7 Test Duration 22

Chapter 3: EPHECT analytical methods ______________________________ 26

Chapter 4: Emission estimations ___________________________________ 28

4.1. Basic Theory 28

4.2. Emission Estimations 33

Chapter 5: Concluding remarks and future considerations ______________ 36

Reference list __________________________________________________ 38

IV

LIST OF FIGURES

Figure 2.1 Diagram of the kinetic processes involved in the mass transfer model of VOCs from

material surfaces.

Figure 2.2 The test chamber concentration measurements pattern.

Figure 2.3 The ideal concentration time profile for a constant emitting source.

Figure 2.4 Test chamber measured limonene concentration distribution from a kitchen cleaning

agent.

Figure 4.1 The measured concentration simplified pattern.

Figure 4.2 The proposed new measurement concentration pattern in a chamber test.

Figure 5.1 The measured concentration simplified pattern.

V

LIST OF TABLES

Table 1.1 Selection of EPHECT consumer products _______________________________________ 1 Table 2.1 Start-up conditions of consumer product emission testing _________________________ 9 Table 2.2 Initial conditions for EPHECT consumer product emission testing ____________________ 9 Table 2.3 The ideal room dimensions and loading factors according to CEN TC 351 WG2 ________ 17 Table 2.4 Experimental conditions to test liquids, packed in a flask _________________________ 18 Table 2.5 Experimental conditions to test liquids, packed in a spray bottle ___________________ 19 Table 2.6 Experimental conditions to test liquids, packed to be volatilized _____ Error! Bookmark not

defined. Table 2.7 Experimental conditions to test solid products; candle emissions ___________________ 20 Table 3.1 Overview of the analytical methods __________________________________________ 20 Table 4.1 Overview of the EPHECT analytical methods ___________________________________ 26

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NOMENCLATURE

Symbol Description Units

A

Rate of adsorption on surfaces in the chamber

[mass units h-1]

C Concentration in the chamber [mass units m-3]

Cext

Concentration of the inlet air

[mass units m-3]

CM Measured concentration within the sampling time

[mass units m-3]

Cmax Peak concentration [mass units m-3]

CT Average concentration over Δt [mass units m-3]

C0 Initial pollutant concentration [mass units m-3]

D

Rate of desorption from surfaces in the chamber

[mass units h-1]

DT

Time interval which includes both the preparation and the sampling time

[hrs]

DTIN Preparation time [hrs]

DTS Sampling time [hrs]

ER Emission rate [mass units h-1]

ER0 Peak emission rate [mass units h-1]

ET Total emission [mass units]

F

Removal rate by an air cleaning device in the chamber

[mass units h-1]

k Decay rate constant [h-1]

N Number of measurements -

Qin

Air flow rate going in the chamber

[m3 h-1]

Qout

Air flow rate going out of the chamber

[m3 h-1]

SER Specific emission rate [mass units h-1 gr-1]

t Time [h]

TIMTEST Total testing time duration [h]

VII

tmax

Time of maximum observed concentration

[h]

V

Volume of the test chamber

[m-3]

X

Rate of generation/destruction through chemical reactions in the chamber

[mass units h m-3]

ΔλN Emission strength factor [h-1]

Δt

Time interval between two successive measured concentrations of the simplified pattern

[h]

λ

Air exchange rate of the test chamber

[h-1]

λd Decay constant [h-1]

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CHAPTER 1: INTRODUCTION

This document addresses the strategy to measure and model product emissions, related to the

household use of consumer products. This is based on the EPHECT project experience and the

available expertise. The strategy more specifically applies to the following 15 product classes,

selected for testing in the EPHECT project.

Table 1.1: Selection of EPHECT consumer products

1 all purpose cleaner

2 kitchen cleaning agent

3 floor cleaning agent

4 glass and window cleaner

5 bathroom cleaning agent

6 furniture polish

7 floor polish

8 combustible air fresheners

9 air fresheners (spray)

10 air freshener, passive units

11 air freshener, plug-in units

12 coating products

13 hair styling products

14 deodorants (sprays)

15 Perfumes

One of the purposes of the EPHECT Project is to explore and develop methods to measure the

emission of air pollutants from the above mentioned products by placing them into a climate test

chamber. The purpose of the present guidance is to present the EPHECT experience (Stranger et al.

EPHECT WP6 report part I and II) together with findings from the open literature and to analyze

advantages, disadvantages, and caveats by applying test chamber technology for chemical emission

testing and associated modeling strategies to estimate emission rates of specific compounds in a

predefined model room.

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CHAPTER 2: CONSUMER PRODUCT TESTING

2.1 Background

In the recent decades, research activities on product emissions were mainly focused on building

material emissions. The resulting emission test procedures, evaluation protocols (e.g. AgBB, Afsset

2009, GEV testing method, etc ) and standards on emission test chamber procedures and sampling

techniques (ISO 16000-3, ISO 16000-6, ISO 16000-9) are well-established. ASTM D6670-01 (2007)

describes a more generic strategy for volatile organic compounds (VOC) emission testing from

materials, products and equipment (building materials, furniture, consumer products, printers, air

cleaners etc.) typically used in office and residential buildings, in full-scale chambers for VOC

emission testing. However, specifically for the consumer and personal care products studied in

EPHECT, dedicated standards for emission tests are currently not available. Test protocols as well as

the results, reported in the open literature, vary between laboratories and are difficult to compare,

mainly due to variable test conditions (ASTM D5116-10, Salthammer, 2009). Therefore, EPHECT aims

at a maximal overlap between the proposed consumer and personal care product test protocols and

existing ISO standards and other relevant emission test/evaluation protocols and standards for

building materials.

In building material emission testing, the products are typically installed as a static object in the test

chamber, with respect to relevant ISO standard (ISO 16000-9), test chamber dimensions, and

reported loading factors; the product emissions are assessed respecting valid emission test protocols.

The selected consumer and personal care products (Table 1.1) consist of products characterized by

exposures related to the household user patterns and user scenarios. Certain aspects of the emission

test protocols proposed in EPHECT may therefore differ from the well-established building material

test protocols, because the emissions will only occur when a certain interaction between the product

and the user takes place: a certain use scenario should thus be simulated in the test chamber.

An important aspect of an emission test protocol is its repeatability for internal use and external

applicability (reproducibility) in emission test chambers of various dimensions. For building material

emission testing, the reproducibility will mainly be function of the product dimensions with respect

to the loading factor and the test conditions (respecting chamber start-up conditions and testing

conditions), in addition to the overall sampling and analytical performance of the individual

laboratory. For consumer product testing, the use scenario itself can additionally have a considerable

impact on the emission test results.

The list of EPHECT consumer and personal care products implies a variety of use scenarios. These use

scenarios are typically a function of the product package (sprays, flasks, etc.) and of the purpose of

the product (floor cleaning agent to be diluted, floor polish to be used undiluted, etc.). The product

package on the other hand is closely related to the aggregation state of the product (solid, liquid or

gaseous). Each package and product purpose thus implies a specific user scenario that should be

simulated in the test chamber protocol, in a reproducible way, in order to assess the emission

characteristics and factors of the consumer product.

When assessing building product emissions in emission test chambers, the emission test result is

typically obtained as specific emission rate per hour and per m² surface (or per kg or per m³ product

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or per unit). It is then used to model its concentration in a reference room. For consumer and

personal care product testing, the units of the emission factors are typically related to the amount of

used products.

Another important aspect is the emission pattern. Two products can be considered as continuous emitting sources of VOCs: passive and plug-in (electric) air fresheners, the remaining are to be considered sources with temporary (short-term) emission patterns. Some of the products form a surface (coating) film during the curing process that alters the mechanism of evaporation of solvents, as discussed below. Other products form initially an aerosol of solvents and additives.

2.2 Pollutant Mass transfer mechanisms

The important questions about emission testing of building and consumer products are; a) what specific pollutants are emitted that may influence the indoor air quality and adversely affect occupants; b) how the emission profiles change over time; and c) are the emission test results meaningful – i.e. are the results independent of test conditions; d) can the results be translated to personal exposure for a risk assessment. In general, the emission can be characterized by two fundamental physical processes (see Figure 2.1), partly taken from Wolkoff et al. (2005).

a) Gas-phase mass transfer (i.e. external diffusion) b) Source-phase mass transfer (i.e. internal diffusion)

Figure 2.1 Diagram of the kinetic processes involved in the mass transfer model of VOCs from material surfaces.

The gas-phase mass transfer model (a) is based on molecular diffusion across a laminar boundary layer as described in equation (1), external diffusion.

)CC(k)CC(D

SER iSgiS

(1)

air

boundary layer

source

Ci

Cs

mi

ms

surface

gas-phase mass transfer(external diffusion)

source-phase mass transfer(internal diffusion)

kg

ks

Figure 3

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SER is the specific emission rate, D is the diffusion coefficient, is the thickness of the boundary layer, CS is the concentration of the target VOC at the source surface and Ci is the concentration of the target VOC in the air and kg is the gas-phase mass transfer coefficient. Process (b) is limited by internal diffusion from the interior of the source to the surface and can be described by equation (2).

)mm(kSER iSs (2)

Here, ms is the mass of the target VOC in the source, mi is the mass of the target VOC at the surface and ks is the source-phase mass transfer coefficient. Comparing emission test results from different chambers, three different scenarios have to be considered.

For kg >> ks: the emission is controlled by the external diffusion process and the thickness of the boundary

layer is directly related to the air velocity above the surface and turbulence, if it is a point source or activity related emission (e.g. spray). This applies to most wet-applied or liquid building products and certain consumer products during the drying/curing phase. Thus, the external diffusion is significantly affected by both surface air velocity/turbulence and the sample loading factor (m2/m3) (and associated vapour concentration within the chamber). The exact timing of the emissions testing is also critical for wet samples, in particular for temporary point sources. During this phase it is therefore paramount to control both air velocity (and/or turbulence), in order to prevent them from influencing/changing the test result. However, for temporary (activity related) point sources like spray products, the air velocity/turbulence becomes difficult to define and measure (which direction), and no harmonized practice exists. Thus, any comparison of such temporary sources will by nature be difficult to compare between laboratories with quite different chamber dimensions without applying rigorous control of all parameters prior to and during testing. However, the extreme sensitivity of the results to such a multitude of variables, does call into the question the reliability of testing wet samples and point sources during the curing/drying stage or use. Further, a vapour pressure effect for such wet-like products cannot be ruled out; thus, some agreed upon test condition is helpful, but not a guarantee for obtaining comparable emission data. Furthermore, it is relevant to envisage that the air velocity becomes less important the larger the chamber dimension; for instance, in a full scale chamber (20 m3) and an air change 0.5/h, the calculated air velocity is 0.05 cm/s.

For kg << ks: the emission is controlled by the internal diffusion process and the influence of the air flow condition in the chamber should be negligible. This applies to most solid building materials and to wet and liquid products after a surface film have been formed. There will be a transition phase where kg and ks compete together; thus, a more difficult situation arises for

kg ks or if the ratio ks/kg changes over time. For an ageing product, ks/kg will normally reach infinity over time. Thus, VOC emissions controlled by internal diffusion (dry products/materials) are largely independent of surface air velocity and loading, provided the exchange rate is fast enough to prevent a vapour pressure effect.

Thus, for consumer product testing, that is characterized by short-term or temporary activity, related emission profiles are generally dominated by external diffusion, but for e.g. creamy products forming a coating an additional internal diffusion may occur. Thus, comparison of emission data obtained

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from different chambers (and even only slightly different test conditions) is by nature encumbered, even if harmonized test conditions are attempted. Two often quoted questions about the outcome of emission testing of building materials in a given chamber are: “does the chamber provide correct SERs” and “how comparable are the round-robin testing results with other chambers”. These questions lead to the implicit assumption that SER data obtained from that particular chamber may be less reliable. These questions are deceptive, especially in view of round-robin testing, because a successful test requires that the results are independent of test conditions, i.e. the emission data are comparable. This is only the case for emissions where the mass transfer rate within the material is slower than in the boundary layer (i.e. “internal” versus “external” diffusion control). However, many other factors influence the SER, of which the most important ones are material homogeneity and laboratory performance (Oppl, 2008; Wolkoff et al., 2005). For consumer products with temporary short-term emission profiles the issue becomes even more difficult, because of the difficulty of defining and controlling exactly identical test and activity conditions. An additional problem is loss of VOCs, if the application cannot be carried out within the chamber itself. In theory, under well controlled environmental conditions and satisfactory recovery (minimal sink (wall) effect) and adequate sampling (according to the objective) and analytical performance, comparable SERs should be obtainable for “internal” diffusion controlled emissions from homogeneous materials, independent of type of chamber. Thus, a third frequently asked question is “whether there exists an ideal chamber providing SER data that would be identical in real scenarios”, i.e. a golden chamber standard. One may ask how meaningful is it to predict (model) externally controlled SERs of VOCs and SVOCs from building materials and consumer products in real life indoor scenarios, in view of the inherent difficulties associated with the use of test chambers. These include all the factors that influence the SERs and external factors. Thus, measured SER in a test chamber, even with adequate recovery and low wall sink effects, may not be representative of the actual SER from the exact same building material/product in a real indoor setting. Well-knowing that chambers versus chambers may differ, in some cases for reasons outside of the performance of chamber itself, one should consider the objective of the emission test itself. Thus, the sampling strategy should reflect the objective of the testing. This in EPHECT means that the emission data should accommodate requirements set by the risk assessment objective, i.e. the associated health endpoints of interest. The important issue here is that the risk assessment focuses on acute effects, semi-acute effects (objective sensory irritation) or longer-term (respiratory) effects. Thus, the sampling strategy should be adopted accordingly, where applicable. With this in mind, one may contemplate the feasibility and meaningfulness of transforming emission data, at least of short-term temporary (point source) emissions to a given model room and assume this reflects the personal exposure. Other emission decay models are available simply by use of the known amount of emitting compounds in the product.

2.3 Parameters that influence the mass transfer

Vapor pressure, gas-phase mass transfer coefficient and diffusion/desorption rate of the organic

compounds are affected by the temperature of the air inside the chamber. Thus, temperature inside

the chamber test must be controlled and recorded during the entire experiment due to the fact that

increase in temperature cause increase in the emissions of VOCs. However, it should be envisaged

that fast evaporation from surfaces results in cooling the surface, thus lowering the rate of emission.

Air change rate is another parameter that plays an important role to the chamber concentration. Air

change rate is expressed in how many change per hour of the air is exchanged at the unit of time

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(n/h). If lower concentrations in the chamber test occur due to an increase of air change rate, the

evaporative mass transfer (external diffusion) may increase affecting the emission rate (ASTM

D5116-10).

Air velocity can be important for the evaporative controlled emissions. In general the higher velocity

leads to increased gas-phase mass transfer coefficient. Because this guidance is dealing with

products used indoors, the test should be done under typical indoor velocities, where applicable and

relevant.

2.4 Selection of test chamber

The key element in the selection of the appropriate test chamber is the objective of the emission

testing. If qualitative information of emitting volatile compounds is required various extraction

techniques may be applied according to product type without the use of a test chamber. The

extraction can be dynamic headspace sampling, purge-and-trap, solvent or thermal extraction

techniques. If the extraction technique is validated it may also provide semi-quantitative information

of the content of volatiles; this may be useful for a conservative exposure assessment under

standardized conditions in a given scenario. Furthermore, mass spectrometric techniques may

provide additional information about the content of non-volatiles compounds.

Historically, test chambers from a few cm3 up to several m3 have been used for quantitative emission

testing and determination of the emission rate of building materials according to ISO and ASTM

standards. A number of comparisons and round robin tests have been carried out during the last two

decades. Generally, the test period has been within three and 28 days, or beyond according to the

objective.

For consumer products the time frame of interest has a different focus. Peak emission rates

(concentrations), which usually occur within 0 to 60 min after the application of a temporary source

(e.g. window cleaner), are used for the assessment of acute exposure and associated acute effects.

Averaged emission rates, that are determined by extended sampling duration, e.g. 6 hours, may be

used for the assessment of longer-term exposures and associated health effects. For constant

sources (e.g. passive air freshener) a constant emission rate is achieved that may be used for both

acute and longer-term exposure assessments.

There are several parameters that may influence the outcome of the emission testing apart from

those discussed above. Among those are two major issues, chamber size and application or

conditioning of the product before starting the test:

Chamber size determines how the product can be applied. The smaller the chamber the

more difficult to prepare the test specimen, in particular spray products within the chamber.

Thus, for small chambers and fast decay emissions that there is a need for outside sample

preparation special care should be taken to minimize emission losses outside

For small chambers temperature control may be difficult during candle testing, thus

unintentional increase of the emission rate may occur.

For chambers of 1 m3 and larger an electronic device can control the dosage for spray

products.

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The application and conditioning can be carried within a full scale (walk-in) chamber.

The larger a chamber, the more becomes effective mixing an issue for achieving “exact”

emission data versus realistic scenario conditions.

Further advantages (+) and disadvantages (-) of chamber size are listed below.

Small chambers (< 0.1 m3) + Provide basic information of emitted compounds + Relatively easy to operate + Heating may be possible + High throughput - Inadequate conditioning (emission loss during application and transport to chamber) for wet,

liquid and pasty products - Inadequate loading versus air exchange rate - Vapor pressure effects that may suppress the emission (saturation), i.e. limited transfer

capability - Difficult to transfer/model emission rate data for exposure assessment - Difficult to test sprays under certain use scenario ( e.g. spraying into the air)

Large chambers (0.1 – 2 m3) + Spray products may be applied inside chambers 1 m3

+ Relatively easy to operate (larger chamber are expensive) + Medium throughput - Inadequate conditioning (emission loss if application outside and transport to chamber) for wet,

liquid and pasty products - Compounds may be lost by excessive dilution (too low concentrations) - Compounds may be underestimated due to wall sink effects - Modelling required for exposure assessment. Modelling of breathing zone concentrations might

be difficult, during and after application

- Larger chambers are expensive Full scale (walk-in) chambers (real test rooms) + Allow realistic user behavior, conditioning and loading within chamber under controlled

conditions + Provide “realistic” environment and concentration + Data be directly translational to exposure assessment + Personal exposure monitoring possible + Air velocity more realistic than in smaller chambers - Compounds may be lost due to dilution (too low concentrations) - Compounds may be underestimated due to wall and other present surfaces sink effects - Effective mixing can be a problem, however realistic, and possibly critical for representative

sampling

- Expensive and may be difficult to operate - Low throughput

2.4.1. Additional considerations

In the selection of the test chamber one has to ensure that undesired effects that may influence the

concentrations of the compounds are minimal. Such effects can be:

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adsorption/deposition of the compounds on the chamber walls and other present surfaces and materials,

re-emission from the chamber wall of the deposited compound,

chemical reaction of reactive VOCs with inlet oxidants (e.g. ozone) may form secondary VOCs.

Nevertheless the selected test chamber has to conform to ISO 16000-9 with respect to recovery and

sink effects of the VOCs measured.

In addition it is recommended that the test chambers are additionally tested with a prescribed

source profile of the VOCs under investigation to check for possible influence of the above

mentioned effects. The VOC source profile needs to reflect to a certain extent the emission profile

that is usually found in the product class under investigation.

For example for products that can be considered as continuous emitting sources the constant source could be the right choice. For products that are considered sources with temporary (short-term) emission patterns it might be advisable to use instantaneous pattern.

2.5 The preparation phase for testing

The testing preparation phase consists of the following three (3) levels:

- Start-up conditions - Initial test chamber conditions - Product specific application procedure

2.5.1 Start-up conditions

The test chamber start-up conditions in the EPHECT consumer product testing procedures are the

same as those reported in ISO 16000-9 (Indoor Air – Part 9: determination of the emission of volatile

organic compounds from building products and furnishing – emission test chamber method). This

implies the installation settings summarized in Table 2.1. The listed parameters have been measured

or set before the experiment takes place and will be kept constant during the experiment.

Table 2.1 Start-up conditions for consumer product emission testing according to ISO 16000-9.

Aspect Conditions

Air supply The emission test chamber has facilities capable of continuously controlling the air change rate at a fixed value with an accuracy of ± 5%

Air flow The deviation of the exhaust flow with the intake flow is < 5%

Air Exchange rate 0.5/h

Sample collection limit The sum of sampling air flows can be up to 80% of the intake flow

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Recovery and sink Using a permeation of diffusion tube, insert a known concentration of toluene and n-dodecane in the chamber, measure the concentration after 72h in the room. The recovery should be > 80%

Air velocity The air velocity above the sample is 0.1-0.3 m/s (accuracy 0.1 m/s) (with an averaging time of 10 minute)*

*) In general, air velocity is not a well-defined parameter and which comes less relevant in full-scale chambers

2.5.2 Initial test conditions

The initial test conditions are also established in agreement with ISO 16000-9. In consumer product

testing these conditions are labeled as ‘initial’ conditions, since the emission tests of certain products

may alter initial conditions. This could for instance occur when assessing the emissions of a diluted

floor cleaning agent: applying the product in the chamber will increase the relative humidity that was

initially set at 50%. They are, however, considering being less critical when realistic user scenario is

simulated.

Table 2.2 summarizes the initial test conditions for consumer product testing.

Aspect Conditions

Temperature 23°C ± 2°C (accuracy of 1.0°C)

Relative humidity 50% ± 5% (accuracy of 3%)

Supply air & background concentrations (TVOC and VOCS)

The concentration of TVOC is below 20 µg.m-3; Individual VOCs occur at concentrations below 2 µg.m-3 (Radiello code 130 – at least 48h, maximal 5 days)

During the experiments, temperature, relative humidity and air flow rate are monitored

continuously.

2.5.3 Product specific test chamber conditions

All emission data measured in the test chamber are recalculated to the ideal room dimensions

(CEN/TS 16516 and CEN TC 351 WG2). This implies a room with a total volume of 30 m3, and an air

change rate of 0.5 h-1. This ideal room consists of a floor of 12 m2, a ceiling of 12 m2, one door of 1.6

m2, walls of 31.4 m2 (excluding door and window) and joints (or small surfaces) of 0.2 m2. Table 2.3

shows an overview of these dimensions. For the windows, reference is made to l’Arrêté sur

l’étiquettage’ NOR : DEVL1104875A and CEN TC 351 WG2, with a surface of one window equal to 2

m2. In case a product can be used on several types of surfaces, the most important surface will be

taken into account (in agreement with NOR: DEVL1104875A). Using the dimensions of this ideal

room in the generation of emission data, will also enable us to refer to EU LCI values. However, a

direct comparison should be carried out with some caution, because LCI values refer to the emission

after 28 days only. Further, LCI values do not necessarily refer to acute effects and respiratory

17

diseases. Furthermore, it is probable that LCI values in the future will consider multiple-source

contribution.

Whenever applicable, the loading factors, related to the ideal room dimensions, are respected in the

EPHECT test protocols. This implies that e.g. a floor cleaning agent will be tested respecting a loading

factor of 0.4 m2/m3 and a window cleaning agent will be applied respecting a loading factor of 0.07

m2/m3. Products to be applied on surfaces (other than floor, ceiling, door, window or walls) will be

tested respecting the loading factor included in Table 2.3 as ‘joints or small surfaces’, as far as this is

a representative loading factor for the use of that product in a room.

Table 2.3 The ideal room dimensions and loading factors according to CEN TC 351 WG2 and CEN/TS 16516

Surface [m2]

Loading factor [m2/m3]

Floor 12 0.4

Ceiling 12 0.4

1 door 1.6 0.05

1 window 2 0.07

Walls (excl. window & door) 31.4 1

Joints (or small surfaces) 0.2 0.007

Because the major influence of the aggregation state on the use and use scenario of a product, the

first division is made into liquid and solid consumer and personal care products.

Liquid consumer and personal care products

Liquid consumer and personal care products include fluids, creams and gels. Depending of the

product purpose, they can be found in different packages. They can be stored (1) in a flask, (2) in a

spray bottle (pistol spray, continuous spray or automatic spray), or (3) in a format to be volatilized.

The test protocol scenarios, proposed in the EPHECT umbrella depend on this product package. All 3

options are discussed below in detail:

Products packed in a flask

Liquid products, stored in a flask, may involve products to be used in a diluted as well as in an

undiluted concentration. They are typically applied on a surface. The type of surface on which the

product is tested should be a representative material, typical for the purpose of the product.

Throughout the EPHECT project, similar products tested in more than one lab will be tested on the

same surface material. However, for full scale chambers, a metal surface (steel) may be preferable to

be able to obtain an even surface.

After the application, the surface may need to be rinsed.

For practical purposes an additional rinsing process after surface drying will interfere in a full scale

experiment. Thus, data obtained from full scale testing might be considered a worst case scenario,

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because there is no information about the rinsing effect. For small chamber testing both application

and eventually rinsing may have to be carried out outside the chamber. The interpretation from

outside conditioning should be carried out with caution due to lost volatiles.

EPHECT consumer and personal care products on which this section applies are all purpose cleaners,

kitchen cleaning agent, floor cleaning agent, (no spray) window cleaner, (no spray) bathroom

cleaning agent, (no spray) furniture polish and floor polish.

It is evident that conditioning outside the chamber results in some loss of volatile compounds. Thus,

the application should be well prepared and the time before insertion into the chamber should be

minimized as much as possible. Ideally, such testing should be carried out in full scale chambers. In

the long run, dedicated application procedures (and test conditions) should be elaborated beyond

those in the umbrella for each product type.

Table 2.4 gives an overview of the conditions for emission testing of liquids, stored in a flask.

Table 2.4 Experimental conditions for liquids, packed in a flask

Aspect Conditions

Loading factor In agreement with Table 2.3

Quantity If diluted use: dilution according to the results from the market study on EU uses and use patterns [Johnson et al 2012] and according to expected (T)VOC levels*. If undiluted use: quantity according to the results from the market study on EU uses and use patterns [Johnson et al 2012] and according to expected (T)VOC levels*.

Scenario Rinse if use scenario prescribes to do so Wet mop in or out room

* This is chamber size dependent and implies that the used quantity may be multiplied if a first test

leads to values below the detection limits of the sampling techniques. After the experiments the

loading factor should be taken into account.

Products packed in a spray bottle

Liquid products packed in a spray bottle will, depending on the product purpose, be sprayed in the

air or on a surface. The type of spraying bottle, and thus the use scenario, will be related to the

product purpose. Products to be sprayed on a surface are packed in a pistol spray bottle; products to

be sprayed in the air will be packed in a bottle to allow continuous or automatic (with electricity

supply) spraying.

In order to avoid spraying on the test chamber walls, the allowed the test chamber dimensions to study these products are restricted to 0.5 m3 or larger.

EPHECT consumer and personal care products, on which this section applies are air freshener sprays

(manual spray or automatic spray), hair styling products (sprays), deodorant sprays, coating product

sprays, and perfumes.

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Table 2.5 gives an overview of the conditions for emission testing of liquids, packed in a spray bottle.

Table 2.5 Experimental conditions for liquids, packed in a spray bottle

Aspect Conditions

Loading factor If spraying pistol (to be sprayed on a surface) in agreement with Table 2.3

Quantity If spraying in the air: spray quantity is limited to 0.5 g of product ( 0.5 s of spraying (per m3 test chamber), or one automatic spray at maximum capacity) and according to expected (T)VOC levels*. If spraying on a surface: quantity according to the results from the market study on EU uses and use patterns (WP5) and according to expected (T)VOC levels*. The product is weighed before and after the testing (accuracy .

Monitoring PM monitoring

Scenario Representative selection of the surface material to be sprayed on.

* This is chamber size dependent and implies that the used quantity may be multiplied if a first test

leads to values below the detection limits of the techniques. After the experiments the loading factor

should be taken into account.

Products packed to be volatilized

Products to be volatilized can be passive units that volatilize without any user interaction, or active

units that require a source of heating. Both types of products, packed to be volatilized, need time to

equilibrate with the surrounding air, before any assessment of the product emissions can take place.

In EPHECT, this period to equilibrate is set on 3 hours (equal to 1.5 air changes).

The only restriction on test chamber dimensions is the size of the product to be tested that should fit into the chamber.

EPHECT consumer and personal care products, on which this section applies, are passive and electric

units. These units may be air freshener units as well as insect repellent devices.

Error! Reference source not found. gives an overview of the test conditions for liquid products,

packed to be volatilized.

Aspect Conditions

Loading factor Not applicable

Quantity If passive unit: not applicable If active unit: position max The product is weight before and after the experiment (accuracy .

20

Monitoring Particle monitoring during testing when active units

Scenario Active units may need electric supply in the exposure chamber

Solid consumer and personal care products

Solid consumer products, considered in EPHECT, are candles.

This strategy is based on available open literature (Derudi et al. 2012), and on the AISE candle

emission test protocol (Petry et al., 2013). The candle should be inserted in the test chamber, large

enough to avoid unintentional temperature increase, with the air flow on and should be lighted in

absence from instructions from the manufacturer with a gas lighter or preferably an electric one (no

pollutants). Then the test chamber must be closed. The candle emissions expected to equilibrate

during 3 hours. Sampling however starts in the period of 0h to 3h after lighting the candle. The

sampling is performed in the following three hours. When the last sampling hour starts, the candle

should be extinguished, and the emissions are monitored during one more hour. For small test

chambers the air flow should be 0.5 m³/h per candle. It should be noted however that in the EPHECT

testing higher flows led to similar outcome. In case of large test chambers an air exchange rate of 0.5

h-1 should be used. The air velocity (speed) in the test chamber in the vicinity of the candle should be

measured without the candle being lighted and should be lower than 0.30 m/s. The air velocity

(speed) with a lighted candle is higher, due to the convection movements caused by the thermal

gradients.

The only restriction on test chamber dimensions is the size of the product to be tested.

For candle emissions special attention should be given to relative humidity and oxygen supply.

Relative humidity should be kept below 75%, in order to avoid wall condensation in the chamber

(AISE protocol for candle emission). The outlet oxygen concentration should not decrease more than

2.5% compared to the inlet oxygen concentration (AISE protocol for candle emission). Table 2.7

shows an overview of the experimental conditions to test candle emissions.

Table 2.7 Experimental conditions to test solid products; candle emissions

Aspect Conditions

Loading factor not applicable

Quantity 1 candle; more than one taking into account expected (T)VOC levels*. The product is weight before and after the experiment.

Monitoring PM monitoring EC/OC assessment O2 monitoring at inlet and outlet Rel. humidity

Scenario The candle is placed on a preconditioned surface in the test chamber. It is lighted in absence of instructions by the manufacturer by a gas lighter or preferably an electric one and then set to equilibrate.

21

* This implies that the quantity may be multiplied if a first test leads to values below the detection

limits of the used techniques. After the experiments the loading factor should be taken into account.

2.6 Testing and Sampling phase

The guidance deals specifically with air measurements of volatile compounds that are measured by

analytical methods. However, emission profiles have been studied in pre-screening experiments,

prior to proposing the measurement patterns. The air sampling takes place during predefined time

intervals with specific sampling time (DTS). The sampling measurement pattern is illustrated in Figure

2.2.

Figure 2.2 The test chamber concentration measurements pattern

Each sampling is completed in time DT (hrs):

DT =DTIN +DTS

where

DTIN is the preparation time for the sampling to follow,

DTS is the sampling time (hrs),

CM is the measured concentration within the time step DTS.

The preparation time DTIN needs to be as short as possible, preferably controlled without opening

the chamber door and disturb the equilibrium in the test chamber.

It is also recommended to apply a predefined and constant sampling time to minimize the overall

uncertainty.

22

The sampling time DTS should be as short as possible to allow for high sampling frequency, at least at

the initial stage of the testing, but also long enough time to allow for reliable analysis, otherwise the

analytical uncertainty increases. This may be relevant in full-scale chambers.

The measured concentration CM is the time averaged concentration within the sampling time DTS.

However for emission estimations it is important to approximate CM with the concentration at a

particular time within DTS, i.e. to the time DTS/2.

This approximation can be valid when 1DTS .

where λ is the air exchange rate of the test chamber (1/hr).

The time interval DT should be as short as practically possible within the analytical capability. It is

better to keep it constant in principle, although it is recommended to be shorter in the initial phase

to show the progression of the emission time profile. For example, setting 1 hour time interval, one

could go to ½ hour interval for the 1st and 2nd time step.

The ideal could be also 1DT

A practical proposal from the EPHECT Project experience is:

hrsDTS 6/1 (i.e. 10 min-keep it the same all the way).

DT(1) = DT(2)= 0.5 hrs.

Other time steps: 1 hr (and constant).

2.7 Test Duration

The test duration is an important parameter to estimate more accurately emissions.

The visual inspection of the measured concentration time profile might indicate the testing time

adequacy as this is discussed below.

For this purpose, we distinguish between two kinds of product types:

products that are considered as nearly constant emitting sources (e.g. passive and plug-in air

fresheners),

products that are considered as sources with temporary (short-term) emission patterns.

Nearly constant emitting sources

The ideal product here is the one that emits with a constant rate. In a test chamber with no

deposition the ideal concentration time profile is shown in Figure 2.3. There is an initial transition

phase of the order of (2/λ) hours with increasing concentration. For longer times the concentration

remains nearly constant. It is noticed that any concentration variability in times well beyond the

transition time can be attributed to variable emission rate and the possibility of pollutant decay due

to chemical activity, wall deposition, or pollutant gain due to wall re-emission.

23

Figure 2.3 The ideal concentration time profile for a constant emitting source

Thus the duration of the test needs to exceed the initial transition time to ensure to capture the

constant level of the emission, i.e. quasi-equilibrium has been obtained in the chamber.

The EPHECT project experimental experience has shown that ideally constant emission rate hardly

exists due to the way the product is emitting. Thus, one needs to check carefully on case by case the

validity of constant emission assumption.

Sources with temporary (short-term) emission patterns.

Here, it is important the duration of the emission test to be long enough to be able to reach the zero

emission time domain.

This would provide:

• more accurate estimation of the (total) emission

• better identification and possibly quantification of additional compound decay due to

deposition or other sink effects

• avoid additional assumptions to extrapolate for the emission beyond the duration of the

emission test

A semi-logarithmic plot of the concentration time distribution together with the zero emission slope

line, reveals if the duration of the emission test was long enough to reach the zero emission regime.

24

(a) (b) Figure 2.4 (logarithmic) test chamber measured limonene concentration time profile from a kitchen

cleaning agent.

The zero emission slope line is the line given by the equation

)exp()( 0 tCtC

It describes the concentration profile in a test chamber with ventilation rate λ in which the initial

pollutant concentration is 0C (an arbitrary number in our case) and the emission rate is zero.

Ideally the time concentration profile tends to be parallel to the zero emission slope line as the

emission rate decays.

In other words, one needs to check how parallel to the zero emission slope line is the last part of the

concentration curve. If it is parallel or nearly parallel then the emission rate has reached practically

the zero value. If its slope is less than the slope of the zero emission line the emission persists. If its

slope is greater than the slope of the zero emission line this means that there is pollutant removal

within the chamber (i.e. deposition or reaction).

Figures 2.4 (a) and (b) show the time concentration curves of limonene emitted from the same

kitchen cleaning agent from two different chambers. In both figures the zero emission slope line is

also plotted.

Figure 2.4 (a) shows that the slope of the pollutant concentration near the end of the curve is less

than the slope of the zero emission line which means that duration of the test was not long enough.

In Figure 2.4 (b) the slope of the pollutant concentration curve near the end, is slightly greater than

the slope of the zero emission line which means that the duration of the test was adequate. In the

latter case however there is a systematic trend in the data of indicating a slight pollutant removal

within the chamber.

Measurements

Zero emission

slope

Kitchen

cleaning agent

test

Kitchen

cleaning agent

test

25

Another way of checking the testing duration adequacy is to take the values of the last two

concentration measurements CM(N) and CM(N-1) and calculate the so called ‘emission strength

factor’ N for the last time step as follows:

)1(

)(1

NCM

NCM

TN

If 0 N then the product continues to emit beyond the testing time. Longer testing time is

required.

If 0 N the product has ceased to emit below the capability of the analytical method.

If 0 N the compound at least during the last time step is decaying within the chamber with a

decay constant Nd .

In the case of the test of Figure 2.4 (b) it was estimated 104.0 hrd .

If the duration of the test is too short, repeated testing is required with a longer test duration.

If the product is applied to a surface it might be also advisable instead of increasing the test duration

to reduce the product mass without violating the recommended loading. It is indicated from the

intercomparison studies of a kitchen cleaning agent that the reduction of the material thickness

increases the emission rate considerably, thus providing total emission estimations with a shorter

test duration. (Stranger et al, 2013).

26

CHAPTER 3: EPHECT ANALYTICAL METHODS

For each compound to be identified, including the EPHECT priority compound, the details on the

analytical method for compound identification and quantification is established. An overview of the

methods is shown in Table 3.1.

Table 3.1 Overview of the analytical methods

Terpenoids: Tenax TA tubes C6-C16 ISO 16000-6 Limonene alpha-pinene geraniol a-terpineol linalool

TD GC MS sample max. 5 l; 20-200 ml/min column: apolar (95%-5%) calibration: methanolic solution of these compounds; spike +/- 5 µl on Tenax tube

Aldehydes: sampling on DNPH tubes; ISO 16000-3

formaldehyde acrolein glutaraldehyde acetaldehyde

check effective sampling range (Waters booklet): 50 l for 10-1000 ppb calibration with hydrazon standards analysis: HPLC-UV or DAD

Aromates:

Benzene toluene xylenes Styrene PAHs: naphthalene & benz-a-pyrene

See terpenoids ISO 16000-12: not possible for test chamber samples Alternative: PDMS/Tenax 150 ml/min – 60 min; TD-GC-MS with cold trap for high boilers

Disinfectants:

chloroamines hypochlorite (H2O2)

Hery et al. (1995) sampling on filter cassette (Teflon filter and 2 impregnated filters with As2O2 and Na2CO3); 1 l/min; 2 hours; IC; result = sum of chloroamines + ClO-

Micl. compounds (not associated with respiratory diseases)

PCBs PCDDs Phthalates Isothiazolinones

see PAHs

CO

NDIR monitor method: EN 14626; or continuous low cost logger Both methods need calibration

NH3

Sampling on Orbo 554 tubes (conform OSHA method ID-188 Analysis: ion selective electrode

NO2

27

ISO 16000-15: short term measurements; continuous analytical monitor chemo luminescence ISO7996; alternative manual photometric reference methods with impinger (Saltzman method) ISO 6768

Silanes/siloxanes/polymers +/- fluorinated

1. Sampling on tenax tubes (see terpenoids) and analysis by GC-MS/MS using both EI and CI. 2. Sampling on quartz filters (e.g. Whatman Grade GF/C - 1.2 um retention, Cat No. 1822-025). Extraction of filters by PLE and subsequent analysis of extracts by LC-MS

Quaternary ammonium chlorides (QUATs)

Sampling on quartz filters e.g. (Whatman Grade GF/C - 1.2 um retention, Cat No. 1822-025). Extraction of filters by PLE and subsequent analysis of extracts by LC-MS.

Particles (spray and combustible products only)

Primary aerosols: Optical method (Grimm), aerodynamic and electric mobility (TSI, Dekati). Size distribution, concentration or particle number Secondary aerosol filter sampling

28

CHAPTER 4: EMISSION ESTIMATIONS

4.1. Basic Theory

The estimation of the emissions from a test chamber experiment is obtained from the emitted

compound mass balance under the basic assumption that the concentration of the emitted

compound within the test chamber is uniform. Otherwise one has to use more sophisticated

modeling tools such as Computational Fluid Dynamics (CFD) tools to estimate the emissions.

The most general form of the mass balance equation in test chambers is given in Equation 4.1

(Kephalopoulos (1999), Salthammer (2009))

XVDACQCQFtERdt

dCV extinout )( (4.1)

where:

C: Concentration in the Chamber (mass units/m³)

Vr: Volume of the test chamber (m³)

ER: Emission Rate (mass units/h)

F: Removal Rate by an air cleaning device in the chamber (mass units/h)

Qout: Air flow rate going out of the chamber (m³/h)

Qin: Air flow rate going in of the chamber (m³/h)

Cext: Concentration of the inlet air (mass unit/m³)

Ads: Rate of adsorption on surfaces in the chamber (mass units/h)

D: Rate of desorption from surfaces in the chamber (mass units/h)

X: Rate of generation/destruction through chemical reactions in the chamber (mass units/m³/h)

In the remainder it is assumed that the test chamber experiment is arranged in such a way that the

emitted compound inlet concentration, removal and desorption as well as chemical activity are

negligible.

In this case Equation 4.1 is simplified as follows

CV

tER

dt

dC

)( (4.2)

It is noticed that Equation (4.2) is equivalent to the one utilised in ASTM D5116-10 Standard.

The measured concentration field is utilised in Equation 4.2 to obtain estimation of emissions.

For this purpose we can distinguish the following cases:

29

Case I: Constant emission rate

In this case Equation (4.2) has an analytical solution

))exp(1()( tV

ERtC

(4.3)

Any measured concentration )( itCM at the time interval 22

DTStt

DTSt ii (see

Figure 2.2) can be used to estimate the constant ER:

]1[)(22

DTS

eeetCMVER

DTSDTS

t

ii

(4.4)

For 1DTS this equation is simplified:

]1[)( it

i etCMVER

(4.5)

Case II: Variable emission rate

The basic assumption that is made for emission modeling purposes is that the concentration

values obtained in the time interval from ti-DTS/2 to ti+DTS/2 equals the concentration value

at the time ti (see Figure 2.2).

As it has been discussed before, such an assumption is quite valid when λ∙DTS << 1 (λ is the

test chamber ventilation rate).

In this case the concentration pattern utilized for the modeling is shown in Figure 4.1.

30

Figure 4.1 The measured concentration simplified pattern.

In this case Eq (4.2) becomes at time ti:

iii CM

V

ER

dt

dCM (4.6)

Emission rate estimation -Option I

Following the ASTM standards (ASTM D5116 10) the numerical solution of Equation (4.3)

yields:

)()( i

i

ii CM

t

CMVtER

(4.7a)

(4.7b)

Such a model in order to be sufficiently reliable needs a dense number of measurement

points which cannot be always the case in this type of measurements (i.e sampling and

analysis).

Emission rate estimation -Option II

A less demanding and more accurate approach is to integrate Equation (4.6) over each it :

)()( 1i

i

iii CT

t

CMCMVtER

(4.8)

2/]t/)CMCM(t/)CMCM[(t

CMii1i1i1ii

i

i

31

where

iti

i dttERt

tER )(1

)( is the average emission rate over it

iti

i dttCt

tCT )(1

)( is the average concentration over it which can be approximated

as follows:

2)( 1 ii

i

CMCMtCT (4.8a)

Emission rate estimation -Option III

If the time steps it are short enough so that one can assume that the emission rate within

the time interval it does not vary considerably and it can be assumed constant the average

emission rate can be estimated analytically directly from Equation (4.6):

IE1

IECMCM

λV

)t(E 1iii

(4.9)

)Δtexp( iIE (4.9a)

Total emission estimation

If TIMTEST is the total testing time duration and N the last time step and ET the total

emission during TIMTEST the integration of Equation (4.6) over test duration TIMTEST gives :

)]([ TIMTESTCTTIMTESTCMVET N (4.10)

where

TIMTEST

dttCTIMTEST

TIMTESTCT )(1

)( (4.10a)

Equation (4.10) can be simplified if )(TIMTESTCTTIMTESTCM N or 0NCM

In this case

)](TIMTESTCTTIMTESTVET (4.11)

The concentration )(TIMTESTCT is obtained from the numerical integration of the

Equation (4.10a).

32

It is recommended the CT(TIMTEST) to be directly measured by sampling the whole testing

period. If this is the case the total emission is then directly measured by applying Equations

(4.10) or (4.11).

It is recommended for quality assurance purposes )(TIMTESTCT to be estimated by both

methods.

Case IIa: Variable emission rate as exponential decay function

Equations (4.7), (4.8), (4.9), (4.10) and (4.11) are valid for any variable emission rate provided

that the measurements time intervals are small enough and sufficient enough so that the

induced numerical errors are not prohibitively high.

If these conditions are not met but it can be proved that the emission rate is decaying

approximately exponentially, one can follow the ASTM Standards [ ] and estimate the

emission rate as follows:

Express emission rate as an exponentially decaying function:

kteERtER 0)( (4.12)

where

ER0 = the peak emission rate (at time t = 0) [μg h-1],

k = the decay rate constant [h−1].

The concentration distribution as a function of the emission rate is given by the equation:

keeV

ERCM ii tkt

i 0 (4.13)

The measured concentrations in Εq. (4.13) are utilized to estimate the unknowns ΕR0 and k

by non-linear regression analysis.

One has to be careful with the selection of the initial values of the unknowns. Following the

ASTM-D5116 instructions the initial value for k is given by the Equation:

maxtkek

(4.14)

where tmax is the time of maximum observed concentration.

33

Finally, the total emission is estimated by the following equation:

k

ERET 0 [μg] (4.15)

4.2. Emission Estimations

Once the measurements and the sample analysis are completed the emissions can be estimated

utilising the above mentioned basic theory.

The following steps can be followed to obtain such emissions.

1st step: Plot the measured concentration time profile in semi-logarithmic scale and normal scale.

Based on expert judgement and what it has been discussed above, check if the profile makes sense

with respect to product and compound tested.

2nd step: Check visually the above concentration time profile graphs and following the discussion in

Chapter 2, try to associate it with one of the three following categories:

Profiles indicative of constant or nearly constant emission source

Profiles indicative of continuous variable emission source

Profiles indicative of decaying emission source

3rd step : Estimate emissions for the category selected as follows:

Constant or nearly constant emission source

In this case the concentration profile for /2it shows constant or approximately

constant behavior.

Theoretically a single concentration selected from the ones measured, is adequate to

estimate the constant emission rate ER by using Equation (4.5) or even (4.4).

It is however recommended to take the maximum measured concentration max][ iCM and

apply Equation (4.5) i.e.

]1[][ maxit

i eCMVER

(4.16)

Concerning the identification of the characteristic emission parameters:

- If the product undergoes relatively significant mass loss during the application it is

plausible to characterise its emission by the specific emission rate in terms of the

product mass loss (m) i.e.

34

m

ER

grhr

gSER

)(

(4.17)

- If the mass loss of the product during the application proves to be insignificant it is more

plausible to express SER in terms of the emitting product surface (A) i.e.

A

ER

mhr

gSER

)(

2

(4.18)

Continuous variable emission source

In this case the concentration profile for /2it shows a relatively significant variation

without a clear decline trend.

For the emission rate estimation, it is recommended to apply Equation (4.8) as explained in

section 4.1

Once the emission rate is estimated as a function of time one can proceed with the

derivation of the characteristic emission parameters.

It is noticed that such an emission behaviour is most probably suggesting considerable mass

loss of the product. Therefore it is plausible to characterise its emission by the specific

emission rate in terms of the product mass loss (m) i.e.

m

ER

grhr

gSER

)(

For better representativeness it is plausible to express emission in terms of average specific

emission rate. By applying Equation (4.8) we obtain:

(4.19)

Equation (4.13) can be exploited for exposure estimations since it is related directly to the

compound mass release within TIMTEST. It is advisable TIMTEST to be of the order of

exposure time or even longer.

For short time exposure (i.e. one hour or less) it is advisable to consider the peak specific

emission rate max)]([ itSER by utilizing Equation (4.8)

Decaying emission source

In this category the emitted compound is released into the air in relatively short time.

TIMTEST

ii ttSERTIMTEST

SER )(1

35

It includes either sprays directly released into the air or product material (liquid/gel/spray) applied to

a surface.

In a test chamber experiment the total emission is derived from Equation (4.10) or (4.11). In the

special case of exponentially decaying emission it can be derived from Equation (4.15)

For exposure estimations it is obvious that one has to work with specific total emission with respect

to product mass which is proportional to the emitted compound content i.e.

m

ET

gr

gSET )(

For sprays directly released to the air this quantity is enough. It is noticed that the release time here

lasts a few seconds. For exposure times of half hour and more the release time is too small compared

with exposure time. This means that we can treat in our exposure calculations the total emission as

an instantaneous release.

For a consumer product applied to a surface one might think for the need of the emission rates. Our

limited experience in EPHECT has shown that the emission rates are sensitive to the application

conditions. In other words, for the same product brand, the same emitted compound, but different

application, in terms of mass, surface area, preparation phase etc we might have emission times

lasting from minutes to several hours. Definitely more research will be needed to come to more

refined conclusions. At this stage for exposure studies it is recommended where it is feasible, the

estimated total emission to be treated as instantaneous release for the calculations. In that case

emission rates are not needed.

Otherwise the emission rate can be estimated from the various options given above i.e.

Equations (4.7), (4.8), (4.9) and (4.13).

For exposure estimations the most preferable is Equation (4.13) provided that the exponential decay

assumption is valid. This approach makes the possible exposure parametric studies relatively easy

since the emission rate is defined by only two parameters: total emission and emission decay rate.

Equation (4.8) is the next choice since it is expected to introduce lower numerical errors due to

relatively limited number of concentration measurements.

36

CHAPTER 5: CONCLUDING REMARKS AND FUTURE CONSIDERATIONS

Within the EPHECT Project a systematic study on the consumer products emissions has started and

the associated difficulties and uncertainties have been explored. The existing knowledge on the

subject has been collected and assessed, a relatively large amount of experimental data have been

produced and analysed and the relative importance to human exposure has been studied.

A comprehensive guidance has been produced on emission testing that includes:

test chamber selection and preparation,

product application,

pollutant sampling and analysis,

test duration,

emission estimation methodology and parameterization.

The concentration pattern produced by the test chamber experiment against the expected behaviour

as explained in the present guidance, may reveal to a large extent possible test chamber or/and

measurement caveats.

Based on the measured concentration pattern, recommendations are given on selecting the proper

modelling option for emission estimation as well as the proper emission parameterization for

exposure studies.

Limited Intercomparison studies have indicated the uncertainty on certain emission parameters on

specific products although further systematic work is strongly needed.

The experience collected from the EPHECT Project has indicated further work at least in the following

issues.

On emission estimation

The present guidance addresses mainly the problem of emissions from consumer products to be

estimated from a discontinuous concentration pattern in a test chamber. Such temporality is

expected to generate numerical errors. The present proposed emission estimation methodology tries

mainly to reduce those numerical errors.

Nevertheless, it is desirable the concentrations to be measured continuously if this is possible.

Otherwise it is proposed to investigate a new discontinuous pattern as indicated in Figure 5.1.

37

Figure 5.1 The proposed new measurement concentration pattern in a chamber test.

It is proposed to sample in addition over the entire it , i.e. to provide experimental values for

)( ii tCT (see Equation 4.8). Then )( itER can be estimated directly from the experiment using

Equation 4.8 without any numerical approximation. There is a need to investigate to what extent the

differences of the experimental errors in the short and long time sampling may affect the quality of

the results.

On emission representativeness

In the above emission estimations from the test chamber concentration measurements the critical

question remains in what degree the estimated emissions can be applied in the real world with

different room volumes, air exchange rates, background concentrations from other sources, and user

scenarios, and including the presence of oxidants. The ambition up to this point was to express

emissions in terms of suitable emission factors that may be directly utilized into real applications and

exposure estimations in real environments. However an extensive parametric testing and

comparison is required covering expected ranges at least in use scenarios, chamber volumes, air

exchange rates and room temperatures. This extensive testing is needed to be accompanied by

detailed 3-D transient computational modelling that considers the important emission release,

transport and removal mechanisms of the emitted compounds. Such an effort is expected to provide

the methods and the tools to translate single test chamber measurements into real world emissions

with the intention to assess personal exposure. Further to this, models are needed to establish the

personal breathing zone exposure in realistic settings.

38

REFERENCE LIST

Oppl R (2008) Reliability of VOC Emission Chamber Testing - Progress and Remaining Challenges. Gefahrstoffe - Reinhaltung der Luft 68:83-86. Petry T, Cazelle E, Lloyd P, Mascarenhas R and Stijntjes G (2013) A Standard Method for Measuring Benzene and Formaldehyde Emissions From Candles in Emission Test Chambers for Human Health Risk Assessment Purposes. Environ Sci Pol 15:1369-1382.

Wolkoff P, Salthammer T and Woolfenden E A (2005) Emission Cells and Comparison to Small Chambers for Materials Emissions Testing. Gefahrstoffe - Reinhaltung der Luft 65:93-98. Stranger M., Maes F., Goelen E., Nørgaard A. W., Wolkoff P., Ventura G., Oliveira Fernandes E., Tolis E., Bartzis J. Quantification of the product emissions by laboratory testing, PART I Consumer product Test Protocol, January 2012. EPHECT WP6 report.

Stranger M., Maes F., Goelen E., Nørgaard A. W., Wolkoff P., Ventura G., Oliveira Fernandes E., Tolis E., Efthimiou G., Kalimeri K., Bartzis J., Letzel T. Quantification of the product emissions by laboratory testing, PART II Results of product testing experiments, April 2013. EPHECT WP6 report.

Johnson A., Elena E. Survey on indoor use and use patterns of consumer products in EU member states, February 2012. EPHECT WP5 report.