| Front page | | Contents | | Previous | | Next |

Total health assessment of chemicals in indoor climate from various consumer products

5 Model calculations of potential indoor concentrations of selected volatile substances and evaluation of its health importance

• 5.1 Assumptions used in the calculations
  • 5.1.1 Model room
  • 5.1.2 Consumer products
  • 5.1.3 Chemical substances
  • 5.1.4 Available data and assumptions for calculations
  • 5.1.5 Special conditions for the single products
• 5.2 Modelling of indoor concentrations
  • 5.2.1 Phenol
  • 5.2.2 Formaldehyde
  • 5.2.3 Acetaldehyd
  • 5.2.4 Benzene
  • 5.2.5 Toluene
  • 5.2.6 Xylen(es)
  • 5.2.7 Styrene
  • 5.2.8 Limonene

The purpose of this chapter is to estimate the total indoor concentrations of pollutants released from every consumer products that people may be exposed to various places in their homes, and make a preliminary health evaluation of such combined exposures.

5.1 Assumptions used in the calculations

The selection of which model rooms, which consumer products and which indoor chemicals should be included in the model calculation and health screening was made in consultation with DEPA and based on the developed substance-product matrix and the priority lists of substances and consumer products (see Chapter 4).

5.1.1 Model room

The model calculations are made for three types of rooms, where the exposure to VOC are supposed to be highest, thus a children’s room, a kitchen/family room and utility room/hall.

5.1.1.1 Children’s room

Infants, children and toddlers, who live in the children’s  room, are the most susceptible to chemical exposures. They stay there for long time when they sleep, play or make school homework. Furthermore, this room is often smaller than other rooms in the dwelling, and many consumer products able to release volatile chemicals to the air may be present.

The model room has a volume of 17.4 m³ corresponding to a typical children’s room in a well-insulated home. That size corresponds approximately to conditions in a standard room with a floor space of 7 m² and a ceiling height of 2.5 m, which normally is used to emission measurements. ^[5],[6] The air flow is defined as 0.5 h^-1.

The size of the room and the air flow correspond to the conditions used for scenario calculations in several of the DEPA reports.

5.1.1.2 Kitchen/family room

In a kitchen/family room various hobby activities take place besides the cooking activities, which all may generate air pollution. The volume of the selected room is set to 52.2 m³, corresponding to a room with a floor space of 21 m² (3 times the space of the children’s  room) and a ceiling height of 2.5 m. The air flow is 0.5 h^-1

5.1.1.3 Utility room/hall

In a utility room and in a hall many activities may pollute the air and it is those places dwellers and guests may carry dirt from outside. The volume of the room is set to 17.4 m³, corresponding to a floor space of 7 m² and a ceiling height of 2.5 m. The air flow is again 0.5 h^-1

5.1.2 Consumer products

From DEPA’s consumer product reports 46 consumer products with probable relevance for the indoor climate were selected. The three model rooms were equipped or decorated with these products, as indicated in Table 5.1.

Table 5.1: Consumer products with relevance for the indoor climate and included in DEPA reports. The figures indicate, how many specimen of a particular product are placed in the model rooms. ”+” indicates that the particular product is in place, e.g. in amounts corresponding to scenario calculations in a relevant report, or that a product is used in the particular model room. It is mentioned, if one of the eight selected substances is found in the particular product, either as content or degassed.

5.1.3 Chemical substances

Model calculations are made for the eight selected volatile chemicals: Phenol, formaldehyde, acetaldehyde, benzene, toluene, xylenes, styrene and limonene.

Table 5.2 is an extract from the large substance-product-matrix on Excel sheet of those consumer products containing at least one out of eight selected chemicals. In the 33 products or product types the 8 substances are determined 107 times. In about 52 cases the substance is released continuously during a longer time, in about 34 cases the substance is released short-term, and in about 26 cases the substance is only determined as product content.

Table 5.2: Products, which may release or contain the selected chemical substances. RX shows the number of the relevant report from DEPA. ”+” indicates if the substance is released continuously over longer time, and ”(+)” indicates that the substance is released over shorter time. Absence of both “+” or “(+)” indicates that no release of the substance is measured, and typically substances were only detected as contents in the product.

5.1.4 Available data and assumptions for calculations

The review of DEPA’s reports on chemicals and consumer products showed that data in the various reports had different character and goal. In some reports the focus is on substance contents in the products, instead of release of substances to the air, which is more relevant dealing with indoor climate. Even for some of the reports dealing with products very relevant for the indoor climate, there is often insufficient data for calculating indoor concentrations. In addition, the results of the chemical analysis are not always specific and certain, because screening methods are often used and quantification of VOCs may be with unspecific toluene-equivalents. For specific details reference is made to the DEPA reports.

Regards products, for which the release of substances to the air are measured and the source strength calculated, results are typically recalculated to potential indoor air concentrations in a standard room based on a simple model. Recalculations of results from climate chamber studies to concentrations in a standard room are typically based on the following standard conditions: It is assumed that the tested consumer products are used in a room with a volume of 17.4 m³ and an air flow of 0.5^-h. This corresponds to a typically children’s room in a well-insulated family house. At a certain air flow the highest concentration of pollutants, anything else equal, will occur in a children’s room, because it is the smallest allowed room according to the building legislation.

In order to carry out the scenario and model calculations in the framework of this project with the given number of substances and products in the three types of model rooms, it has been necessary to use a pragmatic procedure, where the available data is applied in as simple and direct a way as possible. This means that the available and performed scenario calculations in the DEPA reports are used as far as possible. In those cases, where scenario calculations from the reports are not corresponding to the conditions for the three scenarios above, some simple calculations were undertaken, where it is assumed that there is proportionality between variations for ventilation and room size. That means e.g. that if the room is three times as large as in the original calculation, then the concentration is one third. A calculation example is given in Section 5.2.1.

Two types of source are distinguished between:

1. Sources that release substances during shorter time, and
2. Sources that release substances to the air continuously over long time.

Short-term and continuous sources are defined by the measurements available most extensively in the DEPA reports for electronics, after7 hours (new products) and 9 days (used products), respectively.

A "normal" worst-case situation is the basis of the calculations, and the focus is on indoor concentrations after 7 hours (new products) and 9 days (used products). The available indoor air concentrations for the particular products related to the three model rooms are listed in tables, and the concentrations are added in order to get the potential indoor air concentrations after 7 hours and 9 days, respectively.

Contrary to the more steady pollution sources, sources of a more extreme and brief character also appear, e.g. spray painting. These sources are treated separately and are assumed to impact the concentration with a contribution that has to be added to the more continuous (new or used) sources in order to estimate the highest short-term concentration.

For some products, e.g. TV apparatus and incense, measurements have been made on several different products. In such cases the product with the highest concentration is used in scenario calculations. For halogen lamp transformators an average figure of five transformators was used.

5.1.5 Special conditions for the single products

Regards printed matters the focus is that situation, in which the highest exposures are expected, that is watch and reading, when the consumer turns over the pages in the publication. In order to assess exposure in a standardized matter, theoretical exposure scenarios are defined. These shall illustrate worst-case but realistic exposures. The direct exposure of the consumers is supposed to take place, when the printed matter reaches the consumer after 2-15 days (3^rd measurement period), and the consumer turns the pages. The potential concentrations are calculated in a model room of a volume of 10 m³ with an air flow of 0.5 times an hour. These results are used to calculate potential concentrations in the 2 smallest of the 3 scenarios. Thus a "worst-case" scenario was selected, in which pages are turned in three photogravure papers (e.g. sales catalogues) arriving at the same time, thus 498 gram photogravure and 677 gram offset, in total 1,175 kg printed matters in children’s room and in utility room/hall. The release of chemicals is considerably lower, when the pages are not turned.

For incense there is used a consumption scenario, in which one incense pin is burned continuously in one hour in a room of a volume of 20 m³ and an air flow of 0.5 h^-1. The combustion time of one pin varies between 25 -50 minutes. In order to estimate the indoor air levels several scenarios were put forward with the help of a box model and based on measured concentrations. It was chosen to use results from ventilated rooms instead of closed unventilated rooms, since it is more realistic. The room size was deliberately assumed small for the sake of a realistic worst-case with an air flow of 0.5 h^-1.

Regards the study of children’s tents, the product under investigation was placed in a climate chamber at standard test conditions. An evaluation is undertaken based on the highest measured concentration (not recalculated for a model scenario), which occurs 3 hours after unpacking of the product. If that concentration is a matter of concern, the rest of the analytical results measured after 3, 10 and 28 days after outpacking of the product are taken into account.

For products of exotic wood the concentration of the substances was measured in a climate chamber and recalculated to what was relevant in indoor climate connections. The calculations were made for a standard room with a volume of 17.4 m³ and an air flow of 0.5 h^-1. For all products a material load of 0.4 m²/m³ (0.4 m² material per m³ air) was used, which is believed to correspond to e.g. one table and 6 chairs or a floor area of 7 m². By using the same material load for all products it mostly will be worst-case calculations. For every identified substance in the climate chamber measurements, calculations were made for days 3, 10 and 28.

For Christmas spray there was gathered information about product composition from safety data sheets and recipes, thus information exists about the content of the products. In order to evaluate the inhalation exposure of people, the report defines some standard conditions. These conditions are based on the various ways, the products are applied.

Therefore, the calculations are made for two scenarios, namely use of a full spray can in a relatively short time period and secondly use of smaller doses. In the report a small dose is defined as 1/25 of a 150 ml can. When spray products are used, it may happen in different types of rooms. Since some of the products are not supposed to be used indoors, two different conditions, where the products can be used, are included: Garage or similar (3 m x 6 m x 2.5 m) with an air flow of 2 h^-1, and indoors e.g. in a kitchen (3 m x 4 m x 2.5 m) with an air flow of 0.5 h^-1. It is assumed that there is sprayed only once in a period and that all solvents evaporate instantly. The normal equation for decay is used to follow concentrations in air during time. In this way it is possible to get a feeling for, how the circumstances will be during various use conditions.

The exposure calculations for spray paint include some imaginary situations, in which a consumer or his family could be exposed to contents in spray paint. The calculations are built on the following scenario: An adult spray paints an item in an enclosed space at room temperature. The content of the can is sprayed against the item. Parts of the contents hit the item but the rest is released to the air. During this process the user of the can has a great risk of inhale these gaseous or particle-bound pollutants. It is assumed that an applicant uses a simple disposable particle filter to protect mouth and nose, thus only inhalation of gasses and vapors are included in the calculations (and in the present project). Exposures by inhalation are calculated as scenarios for application and drying. The scenario for application is based on substance concentrations determined by chemical analysis, while the scenario for drying is based on the determined amounts of substances. For each of the focus chemicals the highest concentration/amount determined by the chemical analyses was selected to the exposure scenario. These scenarios will, therefore, reflect the realistic worst-case exposures to each focus chemical.

For some products unusual or ”illegal” situations may develop, which may be hazardous to health, e.g. wrongly use of spray products indoors. These products are discussed separately as a problem but should be assessed with other products and other sources contributing the same chemical, e.g. building materials.

If there is data from more than one product from the same product group, the highest release of a chemical is used in the calculations.

5.2 Modelling of indoor concentrations

In the following the results are presented of worst case model calculations of indoor concentrations, based on above mentioned preconditions, for each of the eight selected volatile substances at occurrence of each product, and when the products are present at the same time in the three model room scenarios.

5.2.1 Phenol

The calculated concentrations for phenol are shown in Table 5.3.

An example of the calculations:

The emissions measured in the DEPA reports are transformed to potential indoor air concentrations in a room of 17.4 m² and an air flow of 0.5 h^-1. Regards phenol and pressing iron the concentrations are 1.4 µg/m³ (after 7 hrs) and 0.2 µg/m³ (after 9 days) in Children’s room and Utility room/hall but only a third in the Kitchen/family room.

Table 5.3: The concentration of phenol in a model room with one or more products.

Note: For monitor: Phenol + trimethylbenzene, Tenax-tubes are somewhat oversaturated. Given concentrations are minimum concentrations. The error is in all cases less than a factor 2. For Chargers and transformers: Tenax-tubes are somewhat oversaturated, because of unexpected high emissions, which are seen from the analytical results from the tubes with the two different sampling volumes. Reported concentrations are minimum concentrations. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As seen in Table 5.3, the highest concentrations of phenol are in the children’s room, where the concentration is about 43 µg/m³ for both new and used products.

To this shall be added a potential contribution of 18.6 µg/m³ from tents for children and chloroprene products, for which the following can be stated:

• Regards tents for children the highest concentration of phenol was 18 µg/m³ (in climate chamber) after three hours. This value decreased to 15 µg/m³ after three days and to 7 µg/m³ after 10 days.
   
• Regards chloroprene products, phenol was determined in gloves of chloroprene in a concentration of 0.9 µg/gram. No information was available about release of phenol to the air, thus it is necessary to make some assumptions for estimating a potential worst-case concentration of phenol in the air. It is assumed that the gloves have a weight/volume 1/20 of the waders releasing most toluene, see below. A simple calculation based on the calculations for waders and toluene (0.12 µg/g and a total content of toluene of 0.029 mg) and with this assumption the total amount of phenol in a pair of gloves: 0.9/0.12 x 0.029 mg/20 = 0.011 mg. If it is assumed that this amount evaporates momentarily (unrealistic worst-case) in a hall with a volume of 17.4 m³ it would generate a concentration of 0.63 µg/m³.

It should naturally be emphasized that other sources exist than the mentioned.

5.2.1.1 Health assessment

Above it is mentioned that the maximal worst-case phenol exposure, which is in a children’s room, is calculated to 62 µg/m³. This concentration is much lower than an indoor limit value of 400 µg/m³ based on odour recognition (see Appendix B).

If a child weighing 10 kg inhales the worst-case concentration of 62 µg/m³ the whole day with an inhalation rate of 0.6 m³/time, it receives a total dose of about 900 µg/day or 90 µg/kg bw/day; or a little below the USEPA Reference Dose (RfD) for phenol of 100 µg/kg bw/day developed with a built-in safety factor. This shows that in a children’s  room, where every single pollution source alone counts insignificantly, the total chemical intake can in worst case approach or may be exceed the highest tolerable for a child.

5.2.2 Formaldehyde

The calculated concentrations of formaldehyde are shown in Table 5.4.

Table 5.4: The concentration of formaldehyde in a model room with one or more products.

Reported concentrations are minimum concentrations. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As indicated in Table 5.4 the highest concentrations of formaldehyde are found in children’s room, where the concentration is about 40 µg/m³ for new products and around 18 µg/m³ for used products.

To this shall be added a potential contribution of 515 µg/m³ from textile fabrics, printed matters, incense, tents for children and products of exotic wood, for which the following can be stated:

• For a textile fabric made of 100% viscose, contents of formaldehyde of 43 mg/kg textile have been determined. The theoretical maximum concentration of formaldehyde in air was calculated by using the law on ideal gasses in an approximate form and assumptions that the substance is released instantly to the whole room and is homogenous distributed. The room scenario was selected to a volume of 20 m³, and there are 30 m² textiles, corresponding to 10 kg in the room. Included in the weight is among others bed linen, curtains and clothes. On that basis the theoretical maximum concentration of formaldehyde in air was calculated to 57.6 µg/m³. As mentioned it is a calculated theoretical maximum concentration of formaldehyd, which is not directly comparable with other more realistic determined concentrations. It should also be considered that formaldehyde after a trial wash only was found in one out of three textiles, and that a considerable reduction in the amount of free formaldehyde released from the textiles after one washing.
   
• For printed matters the concentration was calculated based on a scenario illustrating the worst case but still realistic exposures, in which the person turns pages in freshly printed matters in the hall. The potential concentrations were calculated in a model room of a volume of 10 m³ and an air flow of 0.5 h^-1. If this result is recalculated to scenario for a children’s room and a utility room/hall, the potential indoor concentration of formaldehyde becomes 1 µg/m³.
   
• For incense the highest concentration of formaldehyde was calculated to 235 µg/m³ after one hour of constant combustion of one pin of incense in a room with a volume of 20 m³ and with an air flow of 0.5 h^-1(based on a box model). It was calculated that it would take at least 4 hours before the levels of formaldehyde were decreased to typically indoor levels.
   
• Regards tents for children the highest determined concentration of formaldehyde was 163 µg/m³ (in a climate chamber) after three hours. This value was decreased to the half after three days. Since the measured formaldehyde concentrations decreased with time, it will be early hour’s use of the tents where the largest release will take place.
   
• For products of exotic wood calculations were made for a standard room of a volume of 17.4 m³ and an air flow of 0.5 h^-1. For every product was used a material load of 0.4 m²/m³ (0.4 m² material per m³ air). The maximal concentration of formaldehyde in the standard room was calculated to 58 µg/m³(rubber tree), and that is supposed to correspond to worst case.

Some cleaning agents and polishers for metals contain small amounts preservatives, including formaldehyde releasing compounds.

For carpets and hobby glues, formaldehyde was only found as a constituent without emission data.

It should be underlined that other sources than the mentioned may be present. Typical concentration levels of formaldehyde measured indoors in Danish dwellings are around 30 – 50 µg/m³. Sources to formaldehyde in indoor air include some adhesives and glued woodwork such as chip boards, combustion processes, and tobacco smoking. Under normal circumstances the formaldehyde levels in dwellings are estimated to 10-200 µg/m³, depending on which sources are present.

5.2.2.1 Health assessment

The maximal calculated concentration of formaldehyde in indoor air is around 500 µg/m³ but it will typically be below 50 µg/m³. The recommended indoor air limit value of 120 µg/m³ for formaldehyde is complied with at the typical concentration but not in the worst but unlikely case.

A child will normally inhale 720 µg formaldehyde/day at the typical value and 7 mg/day at the worst case. The Reference Dose (RfD) of 0.2 mg/kg bw/day will be complied with in the common case but not in worst case with all sources in operation simultaneously. Because formaldehyde is a recognized carcinogen and a safe limit is impossible to determine, all unnecessary exposure to formaldehyde should be prevented.

5.2.3 Acetaldehyd

The calculated concentrations for acetaldehyde are shown in Table 5.5.

Table 5.5: The concentration of acetaldehyd in a model room with one or more products

Reported concentrations are minimum concentrations. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As it is seen in Table 5.5 the highest concentrations of acetaldehyd are found in the children’s room for new products and in kitchen/family room for used products. The concentrations are around 5 µg/m³.

To this should be added potential contributions of up to 260 µg/m³ from printed matters, incense, tents for children, and products of exotic wood, for which the following estimate is given:

• For printed matters the concentrations are calculated from a scenario, which is supposed to illustrate the worst but still realistic case, in which the consumer turns the pages in printed matter. The potential concentrations are calculated in a model room with a volume of 10 m³ and an air flow of 0.5 h^-1. If the result is recalculated to scenarios for a children’s room and a utility room/hall, the potential indoor concentration of acetaldehyde is 7.5 µg/m³.
   
• For incense the highest concentration of acetaldehyde was calculated to 198 µg/m³ after one hours continuous burning of one pin of incense in a room of a volume of 20 m³ and an air flow of 0.5 h^-1(based on a box model).
   
• Regards tents for children the highest concentration of acetaldehyde is 12 µg/m³ after three hours (in climate chamber). This value decreases to 2 µg/m³ after three days.
   
• For products of exotic wood calculations are made for a standard room with a volume of 17.4 m³ and an air flow of 0.5 h^-1. For all products were used a material load of 0.4 m² material pr. m³ air. The maximum concentration of acetaldehyde in the standard room was calculated to 43 µg/m³ (rubber tree), and it is supposed to correspond to worst case.

Regards hobby glues, acetaldehyde is found as constituent of products but no emission data exists.

It should be underlined that other sources than the mentioned may occur.

5.2.3.1 Health assessment

In the worst case the total exposure from many sources will be 265 µg/m³ but normally it will be lower than 10 µg/m³, thus close to the Reference Concentration (RfC) of 9 µg/m³ determined by USEPA. In a 4-week animal study the no-adverse-effect-level (NOAEL) was 273 mg/m³. With an uncertainty factor of 1000 the tolerable concentration is 0.3 mg/m³ = 300 µg/m³. This is higher than worst-case exposure but because acetaldehyde is a recognized carcinogen, and because a safe limit is impossible to determine for this effect, all unnecessary exposure, e.g. from use of incense, should be prevented.

5.2.4 Benzene

The calculated concentrations of benzene are shown in Table 5.6.

Table 5.6: The concentration of benzene in a model room with one or more products

Note: For monitor the Tenax- tubes are somewhat over saturated. Given concentrations are minimum concentrations. In all cases the errors are estimated to less than a factor 2. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As indicated in Table 5.6 the highest concentrations of benzene are found in children’s room for both new and used monitors and in kitchen/family room for new household ovens. The concentration is about 0.8 µg/m³.

To this should be added potential contributions from incense and oven-harded moulding wax, for which the following estimate is given:

• For incense the highest concentration of benzene was calculated to 353 µg/m³ after one hour continuous combustion of a pin of incense in a room with a volume of 20 m³ and with an air flow of 0.5 h^-1 (based on a box model). It was calculated that it would take up to 8 hours, before the concentration level of benzene has decreased to a typical indoor level.
   
• For oven-hardened moulding wax release of benzene was measured at 200°C, which corresponds to wrong application of the product (worst-case), because in the guideline it is recommended to harden the product at 130°C. At 130°C no release of benzene was measured. At 200°C and after 30 minutes exposure the report mentions that 170 mg benzene was emitted pr. kg sample. It is unclear, if the 170 mg benzene pr. kg sample is released over 30 minutes or is the total long-term release for the product. Therefore, no scenario calculation of indoor levels was undertaken. There could be a relatively short-term and high release of benzene, when the oven is opened.

It should be underlined that other sources than the mentioned may occur. For instance, benzene could be expected to origin from sources as gasoline products used indoors and from car exhaust gasses, which are moved indoors with ventilation air from garages and repair shops.

5.2.4.1 Health assessment

Contribution of benzene to the indoor climate from the few products, which are investigated in the DEPA reports, is <1 µg/m³. That is less than the typical concentration levels of benzene of 3 – 10 µg/m³ measured indoors in dwellings of among others Danish Technological Institute. By using incense, extreme concentrations of up to 350 µg/m³ may develop.

The Reference concentration (RfC) for benzene is 9-30 µg/m³, and an increased risk of cancer is likely at concentrations above 20 µg/m³. In EU a quality value of 5 µg benzene/m³ for outdoor air has to be in force in January 2010. For moulding wax alone there is sufficient safety factor, but this is not the case for a total assessment. In addition, use of incense will generate for short time direct unhealthy benzene concentrations of 350 µg/m³.

The Reference dose (RfD) for benzene is 4 µg/kg bw/day. Normally, a child will inhale < 1 µg benzene/kg bw during 24 hours, however, by using incense the intake during one hour exposure will be up to 21 µg benzene/kg bw/day. Such an intake of a chemical known to cause leukemia in humans must be looked on as completely unacceptable from a health viewpoint.

5.2.5 Toluene

The calculated concentrations of toluene are shown in Table 5.7.

Table 5.7: The concentration of toluene in a model room with one or more products

Note: For monitor the Tenax- tubes are somewhat over saturated. Given concentrations are minimum concentrations. In all cases the errors are estimated to less than a factor 2. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As seen from Table 5.7 the highest concentrations of toluene are found in children’s room, where the concentration was about 49 µg/m³ for new products and about 19 µg/m³ for used products.

To this should be added potential contributions of up to in total 2,980 µg/m³ (or 39,000 µg/m³ with spray paint) from printed matters, incense, tents for children, products of exotic wood, beads, Christmas spray, spray paint and chloroprene products, for which the following estimate may be given:

• For printed matters the concentration of toluene is calculated based on a scenario, which shall illustrate the worst case but still with realistic exposures, where the consumer turns the pages of printed matters. Possible concentrations are calculated in a model room of a volume of 10 m³ and with an air flow of 0.5 h^-1. If the obtained results are converted to scenarios for children’s room and utility room/hall the potential indoor concentration of toluene will be 2,097 µg/m³.
   
• For incense the highest concentration of toluene was calculated to 59 µg/m³ after one hour continuous combustion of one pin of incense in a room with a volume of 20 m³ and an air flow of 0.5 h^-1 (based on a box model).
   
• For tents to children the highest concentration of toluene was determined to 27 µg/m³ after three hours in climate chamber. However, the blind values are about 10 µg/m³, so the measurements must be seen as relatively uncertain.
   
• For products of exotic wood the calculations were made for a standard room with a volume of 17.4 m³ and an air flow of 0.5 h^-1. For all products were used a material load of 0.4 m²/m³ (0.4 m² material pr. m³ air). The maximum concentration of toluene in the standard room was calculated to 74 µg/m³ (caoutchouc tree) and is assumed to correspond to worst case.
   
• For beads concentrations of toluene of 720 µg/m³ may occur. This concentration will only appear as long bead boards are ironed, and it will decrease as soon as the activity is stopped, because there will be a dilution with the other room air.
   
• For Christmas spray the report from DEPA gives concentration in the air of organic solvents and propellants. Products are selected randomly, and in individual cases are used the most precise information, which is recipe information, if it is available. Actual concentrations of toluene are not available.
   
• For spray paint the highest concentration of toluene is determined to 36,000 µg/m³ around the applicant during application of paint. During the following drying period the concentration will be considerably lower.
   
• For chloroprene products, toluene was found in waders in a concentration of 0.12 µg/g. Toluene occurs in concentrations of 0.0046 µg/cm³ in the product, which end up in a total toluene content of 0.029 mg. This amount may in theory evaporate, because toluene is very volatile. Instant evaporation of this amount (unrealistic worst-case) in a hall of a volume of 17.4 m³ might result in a concentration of 1.7 µg/m³.

Regards sealing and shoe care agents toluene was found as constituent but no emission data was available.

It should naturally be emphasized that other sources exist than the mentioned.

5.2.5.1 Health assessment

The highest concentrations of toluene were calculated to be in a children’s room with a concentration of about 49 µg/m³ for new electronics and about 19 µg/m³ for used products. The contribution came mainly from a PC monitor. Moreover to be added is potential contribution from other consumer products of up to 900 µg/m³; however, in total about 2,980 µg/m³ with printed matters and 39,000 µg/m³ including spray paint.

The Reference Dose (RfD) is reported to be 223 µg/kg bw/day and the Reference Concentration (RfC) to be 0.4 mg/m³.

If the toluene concentration generated from en monitor, that is working 6 hours/day, is 50 µg/m³, then a child will have an intake of 120 µg/day or 12 µg/kg bw/day, thus a sufficient safety margin. This is, however, not the case, if contributions from other sources are added. Even without contributions from printed matters and spray paint, the intakes of 1,800 µg/day or 180 µg/kg bw/day are very close to the highest tolerable.

5.2.6 Xylen(es)

The calculated concentrations of xylenes are shown in Table 5.8.

Table 5.8 Concentration of xylenes in a model room with one or more products

Notes: For monitor, TV apparatus and chargers and transformers the concentrations are measured combined for a mixture of o-xylene and styrene. The total value is used (worst-case) and the concentrations for the three xylenes: o-, m- and p-xylene are added. For chargers and transformers Tenax-tubes are somewhat oversaturated because of unexpected high emissions. It is seen of the analytical results from the tubes with the two different sample volumes applied. Reported concentrations are minimum concentrations. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As seen in Table 5.8, the highest concentrations of xylenes are found in children’s room with a concentration of about 105 µg/m³ for new products and about 44 µg/m³ for used products. In the utility room/hall the concentration is about 47 µg/m³ for new products.

To this may be added potential contributions of in total about 476 µg/m³ (or 51,476 µg/m³ with spray paint) from printed matters, incense, tents for children, beads and spray paint, for which the following estimate may be given:

• For printed matters the concentrations of xylenes are calculated from a scenario illustrating the worst cases but realistic exposures, when a person turns the pages of printed matters. The potential concentrations are calculated in a model room of a volume of 10 m³ and an air flow of 0.5 h^-1. If the results from here are converted to scenarios for children’s  room and utility room/hall the potential indoor concentration of xylenes is 17 µg/m³.
   
• For incense the highest concentration of xylenes was calculated to 20 µg/m³ after one hour continuous combustion of a pin of incense in a room with a volume of 20 m³ and with an air flow of 0.5 h^-1(based on a box model).
   
• Regards tents to children small amounts of xylenes were found in all samples. After three hours concentrations were measured to be between 3 µg/m³ and 9 µg/m³. Measurements made after 3 and 10 days resulted in concentrations at the same level or decreasing.
   
• For beads concentrations of xylenes of 430 µg/m³ may occur. Such concentration will only be present as long bead plates are ironed, and it will decrease as soon as the activity ceases, because then it will be blended with the room air.
   
• For spray paint the highest concentration of xylenes is determined to be 51,000 µg/m³ around the applicant. During the subsequently drying the concentration will be considerable lower.
   
• For Christmas spray the report from DEPA gives concentration in the air of organic solvents and propellants. Products are selected randomly, and in individual cases the most precise information is used, which is recipe information, if it is available. Actual concentrations of xylenes are not available.
   
• For sealing and shoe care agents, xylenes were found as constituent, and there is no emission data.

It should be underlined that other sources, than these mentioned, may occur.

5.2.6.1 Health assessment

The highest concentrations of xylenes were found to be in a children’s room with a concentration of about 105 µg/m³ for new electronics and about 44 µg/m³ for used products.

In the utility room/hall the concentrations are about 47 µg/m³ for new products. To this may be added potential contribution of up to 476 µg/m³ (or 51,000 µg/m³ with spray paint).

The Reference Concentration (RfC) for xylenes is 100 µg/m³. The contributions from the electronic products in children’s room alone correspond to that. In case of spray paint the concentrations are so high that there is a possibility of direct health damages, because the exposure then is >10 times the occupational health limit value.

The Reference Dose (RfD) for xylenes is 200 µg/kg bw/day. Exposure to 100 µg/m³ for 6 hours results in a child intake of xylenes at 3,600 µg/day or 360 µg/kg bw/day. That means that alone the electronics cause too high exposures compared to RfD. A further 10-100 times increased exposure, which can be obtained from other sources, might be unacceptable.

5.2.7 Styrene

The calculated concentrations for styrene are shown in Table 5.9.

Table 5.9 Concentration of styrene in a model room with one or more products.

Note: For monitor and TV apparatus the concentrations are measured combined for a mixture of o-xylene and styrene. Reported concentrations are minimum concentrations. The total values are given (worst case). An “X” means here and in the following tables that special conditions are present and discussed below the table.

As seen in Table 5.9 the highest concentrations of styrene are found in children’s  room with concentrations of about 22 µg/m³ for new products and about 8 µg/m³ for used products.

To this may be added potential contribution of up to 772 µg/m³ from incense, tents for children and beads, for which the following estimate can be given:

• For incense the highest concentration of styrene is calculated to 34 µg/m³ after one hour continuous combustion of a pin of incense in a room with a volume of 20 m³ and an air flow of 0.5 h^-1(based on a box model).
   
• For tents to children the highest concentration of styrene is 18 µg/m³ after three hours in climate chamber. Styrene is not treated as a potentially problematic substance.
   
• For beads the figures are uncertain. Bearing that in mind, there may be generated concentrations of styrene of 720 µg/m³. Such concentration will only be present as long bead plates are ironed, and it will decrease as soon as the activity ceases, because then it will be blended with the room air.

It should be underlined that other sources, than these mentioned, may occur.

5.2.7.1 Health assessment

The highest concentrations of styrene were calculated to be in a children’s room with a concentration of about 22 µg/m³ for new electronics and about 8 µg/m³ for used products. In addition, potential contributions of up to about 772 µg/m³ from incense, tents for children, and beads. The latter value is very close to the WHO air quality guideline value of 800 µg/m³ but below the Reference concentration (RfC) of 1 mg/m³ based on effects on the central nervous system.

The Reference dose (RfD) is 200 µg/kg bw/day, which is a little larger than a Dutch TDI of 120 µg/kg lgv/day. At exposure to a concentration of 20 µg/m³ in 6 hours/day, the child intake of styrene is about 72 µg/day or 7 µg/kg bw/day. This is far below any risk level and without health effects. However, in the worst-case scenario for children’s room with incense etc., there will be a 20% excess of RfD.

5.2.8 Limonene

The calculated concentrations of limonene are shown in Table 5.10.

Table 5.10 Concentrations of limonene in a model room with one or more products

Note: For printer measured as toluene equivalents. Reported concentrations are minimum concentrations. An “X” means here and in the following tables that special conditions are present and discussed below the table.

As seen in Table 5.10 the highest concentrations of limonene are found in children’s room, where the concentration is about 4 µg/m³ for new products.

To this may be added possible contributions of up to 341 µg/m³ from printed matters and incense, among others, for which the following may be estimated:

• For printed matters the concentrations of limonene are calculated from a scenario illustrating the worst cases but realistic exposures, when a person turns the pages of printed matters. The potential concentrations are calculated in a model room of a volume of 10 m³ and an air flow of 0.5 h^-1. If the results from here are converted to scenarios for children’s room and utility room/hall the potential indoor concentration of limonene 16 µg/m³.
   
• For stain removers the maximum content of limonene in a liquid product is determined to 0.44%. A worst-case calculation has been made, where a person uses a stain remover in a spray can which is used once a week. Every time the person stayed 5 minutes inside the room, where the application was made. Investigations with three different types of spray cans without propellant but with a hand pump gave an average consumption of 1.3 g at application on a spot of average size. The model room, in which the stain removal takes place, has a volume of 15 m³ without ventilation. It is assumed that after the injection a complete mixing of substances in the air is seen. The concentration in a person’s inhalations zone may be calculated by an equation. This gave a concentration of limonene of 325 µg/m³.
   
• For air fresheners, shoe care agents, and cleaning agents, limonene was found as constituent without emission data.

It should be remembered that other sources than those mentioned may be present. Average concentrations for limonene of 5-15 µg/m³ in indoor air are reported in some studies but concentrations may reach several hundreds µg/m³ during or just after use of various consumer products.^{[7],[8],[9],[10]}

5.2.8.1 Health assessment

The highest concentrations of limonene are in children’s room, where the concentration is about 4 µg/m³ for new electronics. To this may be added possible contribution of up to about 341 µg/m³ from printed matters and incense among others. Exposure to limonene may also occur by storage and consuming of citrus fruits.

Limonene has a low toxicity and the tolerable daily intake (TDI) is 100 µg/kg bw/day. If a child is exposed to a concentration of 4 µg/m³ for 6 hours the intake will be 15 µg/day or 1.5 µg/kg bw/day. Such an intake is completely without health concerns to a normal child. In a worst case scenario, however, the intake may approach the TDI. In case of allergy or intolerance even small amounts may have importance; however, this will not be a specific indoor problem in relation to limonene.

Fodnoter

^[5] Anvisning for bestemmelse og vurdering af afgasning fra byggevarer. DS/INF 90. Dansk Standard, København, 1994.

^[6] NT Building Materials 358: Emission of Volatile Compounds, Chamber Method. Espoo, Finland: Nordtest, 1990.

^[7] Seifert B, Mailahn W, Schulz C, Ullrich D. Seasonal variation of concentrations of volatile organic compounds in selected German homes. Environ Int 1989;15:397-408.

^[8]Fellin P, Otson R. Assessment of the influence of climatic factors on concentration levels of volatile organic compounds (VOCs) in Canadian homes. Atmospheric Environment 1994;28 (22):3581-3586.

^[9] Wainman T, Zhang J, Weschler CJ, Lioy P. Ozone and limonene in indoor air: a source of submicron particle exposure. Environ Health Perspec 2000;108 (12):1139-1145.

^[10]Singer BC, Destaillats H, Hodgson AT, Nazaroff WW. Cleaning Products and Air Fresheners: Emissions and Resulting Concentrations of Glycol Ethers and Terpenoids. Submitted for publication, 2005.

| Front page | | Contents | | Previous | | Next | | Top |

Version 1.0 September 2006, © Danish Environmental Protection Agency