Issue link: https://hi.iaq.net/i/670243
Every breath we take: the lifelong impact of air pollution individual may be indiscernible, effects on whole populations can be significant, as is the case for PM, which affects the heart and lungs, and causes measurable increases in population morbidity and mortality (see Chapter 4). Principal pressures on outdoor air quality come from vehicles and the burning of fossil fuels for energy. Further expansion of road traffic and possible increased energy consumption in buildings because of climate change further add to the burden of pollutants in outdoor air. 2.2 Indoor air 2.2.1 Indoor sources of pollution The quality of the air indoors is important, because it is here that we spend the majority of our time – whether that is at home, at work,* at school, in shops or in vehicles. One important source of indoor air pollution is outdoor air, gaining ingress through windows, doors and general building 'leakiness'. So, 'clean' outdoor air will help to ensure high-quality air indoors. But there are many important and sometimes potent sources of pollution that are located inside buildings and other internal spaces. These include both natural and anthropogenic sources. 2.2.2 Natural pollution sources Natural pollution sources include a number of biological ones. We ourselves release pollutants including a personal particle cloud through normal metabolic processes, and also through use of personal care products. In addition, we often share our indoor environment – both deliberately and unwittingly – with various other living organisms. There are pets of course, dogs, cats and sometimes birds, rabbits and rodents, but also various insects and arachnids that enjoy home comforts, especially including house- dust mites, bacteria and moulds that thrive in warm, moist environments. In addition, cut flowers and potted plants may release pollen into the indoor air. Another important potential source of indoor air pollutants is the soil and bedrock upon which a house or other dwelling is built – a major determinant of exposure to radon, for example. 2.2.3 Anthropogenic sources – the influence of what we do, what we use, and how and where we live There are a large number of potential 'man-made' pollution sources in indoor environments, especially the home (see Fig 3). Probably top of the list in terms of health consequences is the smoking of cigarettes, cigars, pipes etc, giving rise to so-called 'second-hand smoke' containing many noxious substances. In addition, hookahs/shisha smoking, candles, joss sticks and other materials that we burn for recreational purposes emit pollutants into the indoor air. Combustion appliances – cookers, boilers, open fires and portable gas/paraffin heaters (with no flue) – are particularly significant in terms of total emissions. † The building itself, the materials from which it is built and those with which it is decorated are also important potential sources of chemical pollutants – these include the construction materials, as well as paints, glues, furniture, wallpaper and drapery. Cleaning and DIY products, air fresheners and other consumer products such as insecticide sprays that we use in the home are also important. Some 20 © Royal College of Physicians 2016 *Workplaces are considered special situations and are dealt with separately in section 2.3. † It is noteworthy that, in the UK, the use of gas for cooking and heating is particularly prevalent. 8