IAQ | RESEARCH Many debates around indoor air quality will have an impact on the revisions to CIBSE TM40, which will soon be published. CIBSE technical manager Julie Godefroy examines some of the issues FRESH THINKING A key focus for the revision of CIBSE TM40 Health and Wellbeing in Building Services has been to define performance criteria for significant environmental factors, underpinned by scientific evidence from medical bodies such as the World Health Organization and Public Health England wherever available (see the June 2019 CIBSE Journal Health and Wellbeing Special). But the work is constrained by gaps in current understanding, which can be separated broadly into three strands: n How individual environmental factors affect health, comfort and cognitive performance n The impact of combined factors. Guidelines are typically based on the impact of a single factor rather than the concurrent exposure to several factors, as is likely in real life. For example, exposure to air pollution and noise in locations near busy roads, or the effects of cold, damp and inadequate ventilation in low-quality housing n How to cater for a wide range of physiologies, medical conditions, personal preferences and other criteria that contribute to the needs of the individual. Some of these knowledge gaps may be filled in the future; the complexity of others means a precautionary approach will be required, with information accumulated from monitoring over time to evolve a range of environmental conditions and design measures that do not have detrimental effects. Air quality and humidity Broad guidelines for indoor air quality (IAQ) are available as a starting point. In England, for example, the National Institute for Health and Care Excellence (NICE) has recently published a consultation guideline for IAQ in homes.1 However, there are still gaps in a number of areas: n Exposure to multiple pollutants cumulative effects and mixture effects (cocktails), which may reduce or dampen the overall effect n Emerging pollutants, whether new or potentially barely studied for example, those emitted by consumer products such as air fresheners, cleaning or personal care products, or by fire-retardant materials in furniture, furnishings and so on n Effects on cognitive performance and productivity (see panel Effects of internal CO2 levels on performance) 70 September 2019 www.cibsejournal.com CIBSE Sep19 pp70-72 Research Air quality.indd 70 23/08/2019 15:24