ENVIE Co-ordination action on indoor air quality and health effects; WP3 Final report – Characterisation of spaces and source

Abstract

Human exposure to environmental pollutants occurs via various pathways. For many pollutants, especially the volatile ones, air exposure is the dominant pathway. Exposure via air occurs both outdoors and indoors, with diverse types of indoor spaces playing a role, e.g., home, workplace, and passenger cabins of means of transportation. In average people spend over 90% of their time indoors, that percentage being particularly high for some specific groups as new-born, elderly, disabled or sick people. The global exposure to air contaminants is therefore drastically determined by indoor conditions. It is now well established that indoor air pollution contributes significantly to the global burden of disease of the population. For a majority of indoor air contaminants, particularly in the presence of common indoor sources, however, indoor concentrations usually exceed outdoor concentrations, for some pollutants even with an indoor/outdoor ratio of 10 or 20. Emissions are identified, accordingly to the EnVIE approach and grouped into four categories: building materials and related sources, including dampness and moulds; ventilation, natural and mechanical, including, or not, heating, cooling and humidification/ dehumidification; consumer products, furnishing, cleaning and household products; and occupant activities. Emission of chemical substances from construction materials and products in buildings to the indoor air have been reported and reviewed for a wide range of substances, including those formed during secondary reactions, causing complaints of irritation and odour. During the last two decades there has been increasing advances in construction technology that have caused a much greater use of synthetic building materials. Whilst these improvements have led to more comfortable buildings, they also provide indoor environments with contaminants in higher concentrations than are found outside. Wood and cork are now frequently used as a building product for floor coverings, because the material is often regarded as “natural” and “healthy”. However, industrial products, even based on natural raw materials, may contain a number of artificial ingredients and the chemical emissions will strongly depend on the type of additives and the manufacturing process. Modern interior paints are usually based on a polymeric binder. In order to fulfil requirements on e.g., durability, paint contains various functional chemicals. Water-borne paints usually also contains small amounts of approved biocides. Polymeric binders with a very low content of residual monomers have been developed for paint. Besides the release of substances to the indoor air due to primary emission, damp building materials may give rise to volatile substances formed during secondary reactions. Semi-volatile organic compounds (SVOCs) are now receiving much more attention than heretofore. The HVAC (Heating, Ventilation and Air Conditioning) systems as providers, among others, of services of cleaning and dilution of pollutants in the indoor air are also recognized as potential pollution sources. Several studies have shown that the prevalence of SBS symptoms is often higher in air conditioned buildings than in buildings with natural ventilation. 8 The outdoor air introduced indoors through either ventilation systems or natural means is also an important and not always controllable source for the intake of some outdoor pollutants. Outdoor air used for ventilation may also be source of pollution containing particulate matter, particulates of biological origin (microorganisms, pollen, etc.) and various gases like NOx and O building structures which is a driving force for the airflows which will transport to indoors water vapour and gaseous or particulate contaminants. Volatile organic compounds are emitted from a wide variety of household and consumer products with emission rates that are strongly dependent on the type of application and are distributed over several orders of magnitude. A number of product classes are identified and information on ingredients and available data on emissions from individual products are presented. Human activities and the associated use of products encompass a wide range of indoor sources involving release of inorganic gases, particles and organic compounds as a consequence of the activity. For some releases such as with air fresheners the release is a necessary part of the activity to achieve the intended effect whereas for others, such as the release of combustion fumes from a gas appliance, the purpose of the action (in this case generation of heat) is different from the emission. Combustion processes are an important source of a range of air pollutants as carbon monoxide, nitrogen dioxide, sulphur dioxide, particulates and associated inorganic and organic chemicals, organic vapours e.g. formaldehyde, acetaldehyde, and benzene. Sources of these are present in both ambient and indoor environments. The concentrations present in the ambient air provide a baseline for the level of pollutant found indoors as this air enters indoors by processes of infiltration and ventilation. However, the concentration indoors will be modified by processes of sorption to surfaces and chemical reaction depending on the chemical and physical properties of the pollutant and internal surfaces. People themselves are a source of emissions of chemicals and gases, notably CO range of organic compounds that are referred to as body odours. The removal of such body odours is a prime objective of ventilation in order to achieve a satisfactory indoor environment. WP3 aims at to characterize spaces and sources in order to understand where and how to act to guarantee good IAQ. From the two strategies for good IAQ, source control and ventilation, the precautionary principle suggests that first priority shall be given to source control, avoiding, mitigating or simply managing sources of emissions. An overview of all policies on IAQ or related to IAQ, existing or in preparation, directly related to indoor air sources, but also covering outdoor air and industrial emissions, which could affect indirectly IAQ is made. Considering the presented it could be concluded that IAQ is yet poorly regulated at EU level, and in view of that some recommendations are made. The recommendations on policies have taken into account the existing related to IAQ policies such as new EU policies on chemicals (REACH; 2006/121/EC), consumer products (GPSD; 2001/95/EC), construction products (CPD; 89/106/EC) and energy performance of buildings (EPBD; 2002/91/EC) all refer to IAQ issues - suggesting that they could, and probably should, contribute to IAQ policy development and advocate an integrative and comprehensive policy approach centred o