Issue link: https://hi.iaq.net/i/670243
Every breath we take: the lifelong impact of air pollution prolonged low-level exposure to CO. Formaldehyde is important because it is a respiratory irritant and a sensitiser, and is essentially ubiquitous. CO 2 is rarely regarded as a threat to health in indoor environments, but in buildings such as schools it can rise to levels high enough to cause drowsiness, 22 © Royal College of Physicians 2016 Box 6: Key indoor pollutants Pollutants emitted from indoor sources include: • second-hand smoke – from tobacco smoking • CO (and CO 2 ) – from combustion appliances, open fires and burned materials/products; faulty or poorly maintained gas heaters and boilers are a particularly important source • bacteria and viruses – from inhabitants and decaying materials • biological allergens – from house-dust mites, insects, moulds, and animal dander from pets • formaldehyde – from composite wood furniture and fittings, fabric, glues, urea–formaldehyde foam insulation • PAHs, including benzo(a)pyrene – from cooking • VOCs, including benzene, naphthalene and 'essential oils' such as terpenoids – from a wide variety of household, consumer and personal care products • oxides of nitrogen – from combustion appliances • ultra-fine particles – from combustion appliances and cooking • pollen – from plants/flowers • ozone – from electrical appliances • phthalates – from plastic materials • polychlorinated biphenyls (PCBs) and other persistent organic compounds – from old paints, mastics and sealants, plastics and flame retardants • insecticides – from timber, timber treatment, pesticide sprays • radon (a radioactive gas) – from soil/bedrock and building stone • methane – from contaminated ground soil • lead – in dust from old paintwork • mineral dusts and fibres (including asbestos) – from building and insulation material. Box 7: Indoor air quality in schools The recently completed EU SINPHONIE project 12 has revealed significant problems within school buildings, including: • concentrations of PM 2.5 and radon above recommended limits in some schools • levels of CO 2 above 1,000 ppm in some schools • exposure of some schoolchildren to levels of benzene above 5 µg/m 3 • exposure of some schoolchildren to levels of formaldehyde above 10 µg/m 3 • exposure of some children and teachers to high levels of moulds and bacterial endotoxins. Health outcomes linked with environmental exposure include asthma, allergies and various other nasal/respiratory symptoms.