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Total health assessment of chemicals in indoor climate from various consumer products Summary and conclusions
The indoor climate is important for the public health, because we reside far the greatest part of our life’s indoor. Taken together it is expected that Danes spend between 80 and 90 % of their life indoor. In addition, many studies show that the level of air pollution indoor is much higher than outdoor. Therefore, in the Danish National Strategy for Environment and Health indoor climate is a high-priority area. 1.1 The DEPA reports on chemicals in consumer products/articlesIn the years 2002 to 2005 the Danish Environmental Protection Agency (DEPA) has published more than 60 reports on the study of chemicals in various consumer products. About half of these reports contain data and information relevant for the indoor climate but of different aim and character. In some report the focus is on the content of chemicals in the products, in others release to indoor air is included, which is most relevant for this project. The DEPA-reports focus on each consumer product separately. It is more complex in the real dwelling, where many products may be used simultaneously. Most of the reports on consumer products so far published by DEPA conclude that the release of chemicals from one single product does not give rise to concern. However, the collective burden of chemicals from all products used indoor e.g. in the bed room, in the living room, the kitchen or the children’s room, may be a problem. The project had the aim of
In phase 1 of the project all the DEPA reports on consumer products were reviewed, and a short summary in Danish was produced for each report relevant for the indoor environment.. In addition, Excel files containing a substance/product-matrice with indication, if quantitative emission data exist, and if the exposure is short or persistent, was developed, and it is available electronically on www.mst.dk. Furthermore, selected relevant studies in the open literature on release of chemicals from consumer products and contamination of house dusts are reviewed in Appendix A (only in Danish). In this review the focus is on the less volatile brominated flame retardants (PBDE)often used in electronics, textiles and furniture foam, phthalate plasticizers (phthalates) occurring in vinyl floors, vinyl wallpaper and toys, and the water-oil-dirt repellant perfluoroalkylated compounds (PFAS) added to carpets, textiles and outdoor clothes. It is all substances, which have been included in only few of the DEPA reports. Potential indoor concentrations of 8 selected volatile chemicals have been estimated in three model rooms: a hall/utility room, a kitchen/family room and a children’s room, based on pragmatic model calculations with some assumptions and simplifications. This is necessary, because the available data in the DEPA reports have different character and aim, and not necessarily produced with the purpose assessing indoor climate. Further, the determinations of the released chemicals were not always specific and reliable, since screening methods were applied. That could have been fine enough for the purpose of the particular report but if the aim from the start had been to look at the importance of indoor concentrations other procedures may have been selected. It has been presumed that the studied consumer products were representative, adequate and relevant for indoor climate. However, data suggest a large variation within certain product groups. Thus the measured emissions may not be typical for all investigated products, especially if only one product was studied. The products are more likely indicators for the emission from the investigated product type. 1.2 Assumptions in model calculationsThe background for model calculations based on the DEPA consumer product reports has also been that these reports represent the potential most important sources of pollution indoor from consumer products. It should, however, be emphasized that in practice there may exist other important sources than the studied. It is not possible to predict human behavior at home. Situations may develop, where consumer products are used indoor, although others are recommended. Certain times of the year, e.g. at Christmas time, some activities differ from what is normal the rest of the year. I the dark time the use of candle lights increases, and in the cold time many dwellings will have less ventilation applied because of a wish to save energy. However, the opposite may be the case in older draughty buildings. Building technology may also have influence on the healthy conditions in a home, e.g. if water damage occurs and mould grows. Indoor air quality depends on ventilation, temperature and other factors, besides which pollution sources are present. In this report the focus is on the contribution from consumer products but it has to be kept in mind that there may be other sources of the same chemicals in the home, e.g. from tobacco smoking, food preparation and evaporations from building materials (paint and varnishes, integrated carpets etc.). There are a great number of potential sources. The concentration (exposure) of pollutants in indoor air depends mainly on the balance between the pollution sources, and how much cleaner air is supplied to the building (ventilation) to dilute the pollution. Further, the concentration depends on how much pollution is deposited on surfaces (adsorption) or released from surfaces (desorption). In addition, the concentration and composition depend on any secondary chemical reaction occurring in the air or at contact with material surfaces. In the reports from the DEPA, and in this report, the importance of such reactions is not taken into account. Where the focus earlier was solely on the so-called primary evaporation of chemicals from materials, the research focus is nowadays directed at the secondary evaporation. Primary evaporation is release of weakly bound substances, e.g. volatile organic compounds (VOC), used or formed in connection with the manufacture and the material or substances. The primary evaporation occurs mainly, when the material is new. Secondary evaporation consists of VOC formed after the manufacture of the material. The origin may be degradation processes at oxidation of substances in the material surface by ozone. Newly research has shown that secondary evaporation particularly can diminish the quality of indoor air, an din this way have adverse health effects on building users. For some materials this type of evaporation seems to continue in the whole lifetime of the materials. In spite of these reservations regards the performed model calculations, it is concluded that the highest concentrations in a home are likely to occur in the children’s room. The reason is that that particular room normally is smaller than most other rooms in the home, and it contains many products, which may release chemicals to the air. There is a clear tendency that new product release more chemicals to the air than older used products. The products also differ from each other by having different emission patterns. Some release substances over long time, others have a more brief release. Use of incense and some spray products indoor are the most polluting of the studied products and activities, and it emits considerable amounts of hazardous chemicals. 1.3 Assessment of prioritized chemicalsThe maximal exposure to phenol from all sources is calculated to 62 µg/m³. This concentration is much lower than an indoor limit value of 400 µg/m³ based on odor nuisance. The calculated daily intake for a maximum exposed child is then 90 µg phenol/kg, or somewhat below the USEPA ”Reference dose (RfD)” of 0.1 mg/kg bw/d, which has built-in safety factors. This shows that in a children’s room, where a single pollution source may not be important, the total burden to phenol from all sources in the worst case may approach the highest tolerable for children. Normally, formaldehyde levels in indoor air are estimated to 10-200 µg/m³, depending on which sources exist. In this project the calculated maximum concentration of formaldehyde in indoor air was about 500 µg/m³, however, typically the concentration will be below 50 µg/m³. Thus, the recommended indoor air limit value for formaldehyde of 120 µg/m³ is complied with at the typical concentration but not in the worst, however unlikely, case. A child will typically daily inhale 72 µg formaldehyde/kg bw but 0.7 mg/kg bw in the worst case. Thus, the “Reference dose” of 0.2 mg/kg bw/d will be easily complied with for a child in the typical case but not in the worst case adding up all sources working simultaneously in the children’s room. Formaldehyde is a potent carcinogen, and since there is no complete safe limit for carcinogens, all unnecessary exposure to formaldehyde, e.g. from incense, should be avoided. The worst case total exposure to acetaldehyde from many sources will be 265 µg/m³- but normally it is lower than 10 µg/m³; thus close to the USEPA Reference Concentration (RfC) of 9 µg/m³. This RfC is based on the no-adverse-effect-level (NOAEL) for degeneration of the olfactory epithelium in animal studies and with a safety factor of 1000 applied. Since acetaldehyde is a carcinogen, and there is no complete safe limit for carcinogens, all unnecessary exposure to acetaldehyde, e.g. from incense, should be avoided Only two products did release benzene to the indoor climate. The contribution of benzene from plasticine products investigated in the DEPA reports was <1 µg/m³. This is less than the typical benzene concentrations measured indoor in Danish buildings. During use of incense extreme benzene concentrations up to 350 µg/m3 may develop. The Reference concentration for benzene is reported to be between 9 and 30 µg/m³, and an increased cancer risk is reported at concentrations above 20 µg/m³. For plasticine alone the safety factor is sufficient but that is not the case regards use of incense that generates short-term benzene concentrations of 350 µg/m³, which are a direct health hazard. The USEPA Reference Dose for benzene is 4 µg/kg bw/d. Normally, a child will inhale <1 µg benzene/kg bw during 24 hours, however, during use of incense alone the intake during one hours exposure account up to 21 µg benzene/kg bw/d. Such high exposure is completely unacceptable regards a substance proved to induce leukemia in humans. The highest calculated concentrations of toluene were found in the children’s room with a concentration of about 49 µg/m³ for new electronic products and about 19 µg/m³ for used products. The contribution mainly came from one particular PC monitor. To this should be added potential contributions from other consumer products of up to 900 µg/m³, and about 2,980 µg/m³ with printed matters and 39,000 µg/m³ from spray paint included. Tolerable Daily Intake (TDI) and Reference Dose for toluene are 223 µg/kg bw/d, and the Reference Concentration is 0.4 mg/m³. An indoor climate limit for toluene of 8 mg/m³ has been suggested. With a toluene concentration of 50 µg/m³ from a monitor working 6 hours a day a child will have a daily intake of 12 µg/kg bw/d, thus sufficient safety margin. However, this is certainly not the case, if the contributions from other sources are added on. Even without contributions from printed matters and spray paint the intake will be 1,800 µg/d or 180 µg/kg bw/d and very close to TDI. The highest concentrations of xylenes occur also in the children’s room, where the concentrations were 105 µg/m³ for new electronic products and 44 µg/m³ for used products. In the hall/utility room the concentration was 47 µg/m³ for new products. To this should be added a possible contribution of up to 476 µg/m³ (or 51,000 µg/m³ with spray paint). The Reference Concentration (RfC) is 0.1 mg/m³, which alone compare to the contribution from electronics in the children room. In case of spray painting the concentrations are so high that direct health damage may be possible. The Reference Dose for xylenes is 0.2 mg/kg bw/d. Six hours exposures to 100 µg/m³ will correspond to a child intake of xylenes of 360 µg/kg bw/d. Thus, alone the electronics make too high exposure compared to Reference Dose. A further 10-100 times enhanced exposure, which is likely with contributions from other sources, may be seen as completely unacceptable. In the children’s room the calculated concentrations of styrene are 22 µg/m³ for new electronic products and about 8 µg/m³ for used products. To this should be added possible contributions of about 772 µg/m³ from incense, tents to children and tubular pearls. The last figure is close to the WHO Air Quality value of 800 µg/m³ but below the Reference Concentration of 1 mg/m³, whish is based on effects on the central nervous system. The Reference dose is 0.2 mg/kg bw/d, which is somewhat above a Dutch Tolerable Daily Intake (TDI)of 120 µg/kg bw/d. Child exposure to a concentration of 20 µg/m³ in 6 hours a day result in an intake of 7 µg styrene/kg bw/d. This is far below various danger limits and without health effects. However, in the worst scenario for the children room with use of incense etc. there will be a 20% excess of the Reference dose. The highest concentrations of limonene were calculated for the children room, where the concentration will be around 4 µg/m³ for new electronic products. Potential contributions from printed matters and incense of around 341 µg/m³ in total should be added. By-exposure to limonene by storage and consumption of citrus fruits is also possible. Limonene has a Tolerable Daily Intake (TDI) of 0.1 mg/kg bw/d. A child exposed to a concentration of 4 µg/m³ in 6 hours will have an intake of 1.5 µg/kg bw/d. This level of exposure is completely without health risks for a normal child. However, in the worst case scenario the intake may approach the TDI. In case of allergy or intolerance even very small concentrations of limonene may be of importance, however, this will not be a specific problem in relation to limonene in the indoor environment. The available data in the Danish EPA’s consumer product reports on the less volatile phthalates, brominated flame retardants and perfluoroalkylated compounds are very scattered, limited and insufficient to use for an exposure/risk assessment. Therefore, in order to estimate the exposure of the floor crawling children from various sources, these data is complemented with data from other Danish and foreign studies of these chemicals as contaminants in house dust. The most abundant phthalate indoors is di(2-ethylhexyl)phthalate (DEHP). The typical daily child intake of DEHP from all indoor sources will be 10-20 µg/kg bw/d or 100-200 µg/day, however, in the worst case it likely will amount to 50-250 µg/kg bw/d or 0.5-2.5 mg/day for a very exposed child playing on a PVC floor. To be added is intake of DEHP with the food, which is estimated to 18 µg/kg bw/d or 180 µg/day for a child. That is in the same order of magnitude as the ”normal” indoor exposure. This can be compared with the no-adverse-effect level of DEHP in animal feeding experiments with rats, which is 3.7 mg/kg bw/d or 37 mg/day for a child. If rats and crawling children do have a similar susceptibility for DEHP, the safety factor is rather narrow for the mostly exposed children, and that is even without including possible exposure to other phthalates. The levels of brominated flame retardants (PBDE) in house dusts are very variable but, generally, PBDE occur in concentrations one order of magnitude lower than for phthalates. Maximum concentration may be >20,000 ng PBDE/g dust. The exposure to PBDE via house dust is in the same order of magnitude as in food. This is surprising for persistent organic pollutants, for which the food normally account for approximately 90% of human exposure. If the estimated intake of dust is 100 mg/day a child can have an intake of 30 and in seldom cases up to 2000 ng PBDE/day. This should be compared with an average intake from the food of 40-150 ng/day and about 2000 ng/day for nursing infants, because human milk contains relatively high levels of PBDE. Based hereupon the maximum child intake will be <5 µg/day. Comparison with the Reference Dose (RfD) of 2, 3 and 10 µg/kg bw/d for penta-, octa- and deca-BDEs, respectively, which includes sufficient safety factors, shows that only nursing infants may come close to the Reference dose. Therefore, with the present knowledge, the indoor exposure alone will have no health risks. Perfluoroalkylated compounds (PFAS) are not lipophile. Thus intake of animal fat and food in general will not be so important an exposure source as for the lipophile persistent organic pollutants (POP). Indoor climate seems to be the major source of exposure to these substances. If the daily intakes of house dust are set to 100 mg/day, the daily average exposure of a child be 200-2,000 ng PFAS and the maximum 8-50 µg PFAS/day or 0.8-5 µg PFAS/kg bw/d. This corresponds very well to the exposure scenarios in DEPA consumer report no. 50 about impregnation agents. The acceptable daily intake for perfluoroalkylated compounds is 3 µg/kg bw/day; that corresponds to the no-effect level for reproductive effects with a safety factor of 1,000. Only in the case of maximum exposure the intake will be unacceptable. However, the present knowledge about the toxicology of PFAS is limited. 1.4 Mixed exposureIn a home there may be many different consumer products and e.g. building materials which altogether may release many different substances in a complex mixture. In the reports from the DEPA and in this report the health assessments are mainly based on one substance a time. The combined impacts of more/many substances present in the same time are not evaluated. Children staying indoors are exposed to many substances simultaneously. That means possibility of additive effects, and formation of secondary pollutants. In the classical risk assessment paradigm both substances and group of substances are treated separately ignoring that these combined effects may change the picture completely. Knowledge of such cocktail effects is simply lacking. In the DEPA reports the focus is on direct adverse health effects from degassing from particular products. In a broader health perspective issues such as comfort and well-being, including experience of air quality should be taken into account. According to the World Health Organization (WHO), health is not only absence of disease and weaknesses but also a state of complete physical, mental and social well-being. Many pollution sources indoors, including consumer products and building materials, contribute with bad-smelling substances and may affect the perceived air quality (PAQ). Both from a health viewpoint and regards how the air quality is experienced indoor, it is important that adjust the amount of supplied outdoor air to the home, thus meet the demand of ventilation. Ventilation may be limited in many rooms in the dwelling. In some occasions in newer, well-insulated and sealed dwellings air flows less than 0.5 h-1, which is required according to current building legislation, and is used in model calculations in this report. There are for instances found dwellings with an air flow of only 0.25 h-1. If everything else was equal that would result in twice as high concentrations. In this connection it is important to focus on source emission control, thus limit emissions from indoor pollution sources as much as possible. Thus it is important to take into account that placement of computers and other pollution sources in such rooms may introduce an increased need for ventilation. Then the need of ventilation will be less and energy be saved. That is especially relevant with the tighten energy requirements in the new building legislation. In a dwelling there will often be an exchange of air between rooms and between neighbors apartments, in this way a source may pollute the air inside other rooms than, where the source is located. 1.5 RecommendationsIn order to establish a more true/credible basis for assessing the state of health in a Danish dwelling, the following studies are recommended:
In addition the following initiatives are recommended:
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