LAUSR

Air pollution particularly that generated by traffic has recently gained almost unprecedented international attention andmedia headlines, notably those concerning deaths and illness attributed to particulate matter and nitrogen oxides, as well as failures in Europe to meet regulatory ambient air quality standards are driving politicians to act to address this pervasive issue. While measures such as street design or tree planting and ‘apps’ to guide pedestrians and cyclists along low traffic routes to reduce exposure to pollutants are part of the debate, the solution must be source control, whether closing streets to traffic or changing to ‘clean technology’. Similarly, with respect to indoor-generated pollutants, it has long been recognised by the scientific community that source control is the primary strategy to achieve good indoor air quality with ventilation providing themeans to remove any residual pollutants including those generated by the occupants themselves. The particular importance of source control has been highlighted in European expert group recommendations concerning revision of the Energy Performance of Buildings Directive in order to give due regard to indoor air quality when designing, constructing and operating new and refurbished energy efficient buildings. While simple in concept, achieving effective indoor source control has proved challenging in practice. Implementation of policies and actions to improve indoor air quality requires a broad recognition that there is a problem and that there are practicable solutions with appropriate cost–benefit outcomes. As has been the case with outdoor pollution, apportioning health impacts to particular indoor pollutants is complex. To date, few studies have sought to assess the health impact of indoor air pollutants and the European ‘Envie’ project is notable for tackling this topic and highlighting further research needs. However, just as the study of indoor environments requires an inter-disciplinary approach, the effective governance of the indoor built environment invariably requires inter-department action in government which can be problematic to deliver without a clear lead at both national and international level. Besides environmental tobacco smoke (ETS) and radon, the most widely recognised IAQ problems are linked to internal sources of water (and humidity) encouraging mould and dust mites and the health issues associated with building dampness. The hazards of combustion fumes from cooking (and heating) are also well described with respect to both developing and highly developed societies. While these issues are well recognised and the subject of action by governments, they remain significant risks to population health. Even more difficult therefore is to tackle more subtle issues including our exposure to chemicals through the off gassing and in-use release from products used to construct and furnish our built environment and meet our needs as consumers. This is particularly daunting when considering chemicals such as volatile compounds where numbers of individual compounds are potentially large and there is potential for exposures to widely differing mixtures of compounds depending on the source characteristics. A recent review reported 1840 compounds to have been associated with humans, including 872 in human breath. By the end of the 1990s, 100,000 chemicals had been registered in the European Inventory of Existing Commercial Chemical Substances, but very little is known about the toxicity of the vast majority of them. An expert review found that indoor air may contain over 900 chemicals, particles and biological materials with potential health effects. Construction materials and fitments have long been recognised as potential significant sources of indoor chemicals and one that is more readily controllable than the disparate range of consumer products with uses that are highly occupant dependent. The benefits of source control for IAQ and occupant health were recognised by European regulators in the 1980s and this was encompassed in the Essential Requirement (ER) No. 3 of the Construction Products Directive (CPD) in 1989 (European Council