Issue link: https://hi.iaq.net/i/670243
waterproofing/filling DIY products can contain highly asthmagenic di-isocyanates, for example. It is now known that pieces of electrical equipment, including scanners and photocopiers, also emit pollutants – and for houses with built-in garages, the ingress of vehicle exhaust and vapours from petrol, stored paints and solvents, etc can affect the quality of indoor air in the home. Educational establishments (see Box 7), shops and offices may have additional sources of pollution – relating to activities and/or stored items – including materials that emit VOCs. The principal pollutants emitted from indoor sources are shown in Box 6. Additional compounds may be generated through chemical reactions between certain pollutants in indoor air – for example, between ozone and VOCs – forming complex new organic substances. Also, water vapour production in homes (and condensation due to poor building design/construction etc) is important because it encourages the growth of moulds and house-dust mites, and because damp homes are known to be unhealthy homes. The possible health consequences of exposure to the substances listed in Box 6 have been well evaluated elsewhere; 9,10 potential health impacts include asthma, chronic obstructive pulmonary disease (COPD), respiratory irritation, effects on the heart, and cancer,* as well as non-specific symptoms such as headache, tiredness and loss of concentration (sometimes referred to as 'sick building syndrome'). According to the European INDEX project, 11 the most significant of these pollutants (excluding tobacco smoke – see below) in terms of health impact are formaldehyde, NO 2 , CO, benzene and naphthalene. CO is of special concern because it is known that acute exposure can cause collapse and death. It is all the more deadly because there are no warning signs and the early symptoms can resemble those of food poisoning. 8 Moreover, certain persistent health effects may occur following high-level acute exposure or © Royal College of Physicians 2016 21 Bedrooms Dust and dust mites, bacteria and viruses, pet dander, VOCs from personal care products Attic Man-made mineral fibres, asbestos, formaldehyde, dust Bathroom Mould and mildew, bacteria, VOCs and other chemicals from cleaning products Living areas Radon from soil/bedrock, CO and NO 2 from fires and wood-burning stoves, VOCs and formaldehyde from carpets, paints, glues, furniture and air fresheners, tobacco smoke, pet dander Kitchen CO, NO 2 and particulates from gas cookers/stoves, VOCs from household cleaning products Garage CO from car exhaust, mould and mildew, VOCs from stored paints and solvents, pesticides and herbicides Fig 3. Sources and types of indoor pollution encountered in homes. VOCs = volatile organic compounds. Please note that these lists are not exhaustive and that the actual pollutants present, and their amounts, will vary from household to household. *Second-hand tobacco smoke, benzo(a)pyrene, radon, benzene and asbestos are established human carcinogens. 2 The air we breathe