Emissions of volatile organic compounds (VOC)

In document Hazardous chemicals in construction products (Page 39-42)

VOC emissions from construction products can vary over time and are controlled by mechanisms for transporting the substances within a material, such as diffusion and evaporation43. Temperature, relative air humidity, air renewal cycles and the substance’s initial concentration in the product are the key factors affecting the extent of the emissions44. Concentrations of VOCs in indoor air where construction products provide sources usually fall from quite high initial concentrations to a low and almost constant level within a couple of months up to a year from when construction takes place45.

A typical indoor environment can contain more than 6,000 organic substances, of which around 500 can be attributed to construction products46. VOCs occur in indoor environments in a gas phase. Linear and branched aliphatic hydrocarbons (such as nonane, decane,

trimethylheptane) and aromatic hydrocarbons (toluene, ethyl benzene, xylenes) are used as solvents and constituents in paints, varnishes, adhesives and floor coverings. Oxygen-

containing organic compounds such as aldehydes (formaldehyde, hexanal, benzaldehyde and furfural from, for instance, particle boards or floor boards made of cork), alcohols (phenol, heptanol, nonanol from flooring and carpets), ketones (acetone and butanone from paints) and unsaturated substances, such as styrene or vinyl acetate (residual monomers from plastic flooring and wallpaper) also commonly occur.

In the case of eight of the identified VOCs which are carcinogenic, mutagenic or toxic for reproduction, emissions data has been reported in the scientific literature. The emissions data which has been identified in the scientific literature for VOCs is described briefly below. A more detailed description features in the consultant’s report47 and a summary is also provided in Appendix 6. There is also emission data reported for several other VOCs in the literature, but these are not covered by the analysis carried out for this assignment.

Emissions can be split into primary and secondary emissions. Primary emissions are emissions of substances directly from different materials and generally originate from the various constituents in the material. Secondary emissions are largely affected by both current and previous indoor conditions. They originate from several different processes, including re- emission from materials indoors. If the ventilation is reduced during the night, the

concentrations of substances in the air will increase. These substances stick to different surfaces and are emitted later when the ventilation increases and the concentrations in the air drop. Secondary emissions can also occur if new compounds are formed through chemical reactions in the air or on surfaces48.

43 Won D. and Shaw C.Y., 2004. Investigation of building materials as VOC sources in indoor air. National Research Council Canada, report NRCC-47056.

44 Blomfeldt T, Bergsjö P, 1998. Impact of air velocity, temperature, humidity, and air on long-term VOC emissions from building products. Atmospheric Environment 32, 2659-2668.

45 Järnström H., Saarela K., Kalliokoski P., Pasanen A.-L., 2006. Reference values for indoor air pollutant concentrations in new, residential buildings in Finland. Atmospheric Environment 40, 7178–7191. 46 Wargocki P., 2004. Sensory pollution sources in buildings. Indoor Air 14, 82-91.

47 Swedish Chemicals Agency 2015, PM 9/15, Kartläggning av farliga ämnen i byggprodukter i Sverige (Survey of hazardous substances in construction products in Sweden), IVL

48 http://www.kominmiljo.eu/materialemission

A number of studies report on emissions of formaldehyde from such materials as solid wood, particle boards, plywood and wood-based composite materials for walls and flooring, as well as on how the emissions depend on wood species49, 50 and how they change over time51, 52. Formaldehyde can also be formed as a secondary product after treating wood-based

construction products with infrared or ultraviolet radiation53 or ozone54. Both primary and secondary emissions of formaldehyde from construction products are described in the literature55, 56.

Emissions of furfural and phenol have been reported from composite cork products for indoor use, such as walls, ceilings and floors made of or covered with cork57. Emissions were high, but they subsided fairly quickly. Emissions of the volatile substances toluene, n-butyl acetate, ethyl benzene and m-, p-xylene from a wood-based composite material made from several different wood fibres have been reported58. The emissions increased as the temperature increased and, to a lesser extent, as the air humidity increased. The relationship between the substances’ boiling points and emission factors were linear with a negative slope confirming that the most volatile substances are also emitted the most easily from materials. The emission of styrene from a specially manufactured material also increased linearly with the

temperature, but was considered not to be affected noticeably by air humidity59. Emissions of formaldehyde, acetaldehyde and toluene have been reported in a study on conventional and “green” construction products60.

Emissions of the VOCs toluene, phenol, styrene and 2-ethyl-hexanoic acid have been reported from paints, adhesives, plasterboard and combinations of these materials which occur in wall structures61. VOC emissions from complete walls differed from emissions from individual materials/products, which means that emissions testing should be carried out on actual material combinations and not on constituent materials separately in order to obtain a comprehensive view of the emission levels.

49 Schripp T., Langer S., Salthammer T., 2012. Interaction of ozone with wooden building products, treated wood samples and exotic wood species. Atmospheric Environment 54, 365-372.

50 Böhm M., Salem M.Z.M., Srba J., 2012. Formaldehyde emission monitoring from a variety of solid wood, plywood, blockboard and flooring products manufactured for building and furnishing materials. Journal of Hazardous Materials 221-222, 68-79.

51 Horn W., Ullrich D., Seifert B. 1998, VOC emission from cork products for indoor use. Indoor Air 8, 39-46. 52 Fjästad M., Englund F., Ferm M., Karlsson A, Mattson E., 2010. Bevarande inomhusmiljö? (Preserving an indoor environment?) National Heritage Board Report RAÄ 2010, SBN_978-7209-566-3.

53 Kagi N., Fuji S., Tamura H., Namiki N., 2009. Secondary VOC emissions from flooring material surfaces exposed to ozone or UV radiation. Building and Environment 2009, 44, 1199-1205.

54 Nicolas M., Ramalho O., Maupetit F., 2007. Reactions between ozone and building products: Impact on primary and secondary emissions. Atmospheric Environment 41, 3129-3138.

55 Gall E., Darling E., Siegel J.A., Morrison G.C., Corsi R.L., 2013. Evaluation of three common green building materials for ozone removal, and primary and secondary emissions of aldehydes. Atmospheric Environment 77, 910-918.

56 Cheng Y.-H., Lin C.-C., Hsu S.-C., 2015. Comparison of conventional and green building materials in respect of VOC emissions and ozone impact on secondary carbonyl emissions. Building and Environment 87, 274-282. 57 Horn W., Ullrich D., Seifert B. 1998, VOC emission from cork products for indoor use. Indoor Air 8, 39-46. 58 Lin C.-C., Yu K.-P., Zhao P., Lee G.W.-M., 2009. Evaluation of impact factors on VOC emissions and concentrations from wooden flooring based on chamber tests. Building and Environment 44, 525-533.

59 Crawford S., Lungu C.T., 2011. Influence of temperature on styrene emission from vinyl ester resin thermoset composite material. Science of the Total Environment 2011, 409, 3403-3408.

60 Cheng Y.-H., Lin C.-C., Hsu S.-C., 2015. Comparison of conventional and green building materials in respect of VOC emissions and ozone impact on secondary carbonyl emissions. Building and Environment 87, 274-282. 61 Wirtanen L., 2006. Influence of moisture and substrate on the emission of volatile organic compounds from wall structures. Doctoral dissertation. Helsinki University of Technology, Espoo, Finland. ISBN 951-22-8011-6.

4.1.1 Health-based guidelines for construction products – EU-LCI

A health-based evaluation of emissions from construction products is an important part of the existing national legislations. There is a process going on of harmonising emission

evaluations within the EU, based on the LCI (Lowest Concentration of Interest) concept62, 63. The advisory group for EU-LCI includes, for instance, experts, representatives from the European Commission, a number of Member States, as well as the chemicals and construction product industry. A policy decision on EU-LCI is still to be made.

The resulting values are known as EU-LCI values. The EU-LCI values are calculated on the basis of the existing national assessment systems available for VOC emissions from

construction products in Germany (AgBB system) and France (ANSES). Voluntary systems in other countries such as Denmark and Finland have also been used as a basis, along with existing emissions data from construction products. The aim of using EU-LCI values is to enable VOC emissions from construction products to be assessed on a harmonised basis using health-based values.

At present, only volatile organic compounds (VOC) have been assessed in terms of EU-LCI values, with very volatile organic compounds (VVOC), semi-volatile organic compounds (SVOC) or carcinogenic substances not yet being included systematically in this process. It is also important to be able to revise the list of EU-LCI values, both with regard to the types of substances and how many substances are included, along with their respective EU-LCI values. New information may emerge, such as data arising via the implementation of the REACH regulation or through national activities, which will mean that the list of EU-LCI values may need to be revised.

EU-LCI values are health-based reference concentrations for exposure through inhalation, which are used to assess emissions from a construction product after 28 days. EU-LCI values are used in product safety assessment in order to avoid health risks associated with long-term exposure. EU-LCI values are based, as far as possible, on the values established previously in Germany and France. In the case of substances where the values from Germany and France differ greatly or if no previous values are available, values may be calculated, based on the guidelines for assessing chemicals available at EU level64. When a new EU-LCI value is calculated, relevant toxicological data is collated for the individual substance, which gives an overview of the information available for a substance and establishes on what basis the EU- LCI value has been calculated.

EU-LCI values have been calculated for a number of priority substances. A total of 177 substances are listed, which have been split into two groups. The first group contains 82 substances with agreed interim EU-LCI values, while the second contains 95 substances for which EU-LCI values still have to be calculated.

The established EU-LCI values can be used to assess emissions of single substances, but also to look at the overall hazard ratio, i.e. the sum of individual ratio between the measured concentration of a substance and the substance’s EU-LCI value for all substances emitted from a product. The hazard ratio is independent of the type of effect caused by the individual substances.

62 JRC, 2013. Report No 29, Harmonisation framework for health based evaluation of indoor emissions from construction products in the European Union using the EU-LCI concept.

63 www.eu-lci.org

64 http://echa.europa.eu/support/guidance

The occurrence of VOCs and SVOCs in the indoor environment may depend on emissions from different sources, with construction products being an important source among these. EU-LCI values do not take into account emissions of substances from sources other than individual construction products. However, as a way of approaching the issue of emissions from multiple sources, it has been suggested that the individual hazard ratios for different construction products can be specified or that the emissions of individual substances can be limited, for instance, to half the EU-LCI value. The responsibility can also be placed on the client planning a building not to select products which emit the same substances.

The establishment of EU-LCI values is a pivotal part of creating a harmonised framework for labelling construction products intended to be used in an indoor environment. They values have a potential to be used in the EU in order to promote greater protection of citizens’ health in relation to emissions from chemicals from construction products present indoors.

4.1.2 Emissions from flooring, walls and ceilings

It is well-known that different types of flooring can emit chemical substances. The European Commission’s research directorate – the Joint Research Centre – published in 1997 a work focusing on the assessment of emissions from flooring materials. This work was then used as the foundation for the AgBB system practiced in Germany65 (a more detailed description is provided in Chapter 7). Emission tests have identified a number of different substances such as cyclohexanone, 2-ethyl-1-hexanol, alpha-pinene, beta-pinene, decane, hexanal, 3-carene emitted from vinyl flooring, waxed wooden floors, oiled wooden floors and homogeneous wooden floors made of different types of wood.

An analysis has been carried out in Belgium of emissions from construction products used for walls and ceilings66 as part of a review of the Belgian legislation (see more about Belgian legislation in section 7.2.3). Emissions data has been studied from around 300 different products used for wall and ceiling sections. The products covered by the analysis were paints and varnishes, adhesives, sealants, ceiling panels, plasterboard, wallpaper, wall panels, plywood and fibreboard. Some examples of the emissions measured from these materials were benzene, acetaldehyde, formaldehyde, 2-butoxyethoxyethanol, 1-methyl-2 pyrrolidone, decane, undecane, naphthalene, phenol, 2-octenal, 2-methoxyethanol and terpenes.

In document Hazardous chemicals in construction products (Page 39-42)