Over the years, different approaches and indices have been used to define indoor air quality. The most frequently used, recognized widely by the public and equated with indoor air quality are, of course, ventilation rate and concentration of carbon dioxide. Other approaches define the levels of dissatisfaction with acceptability of indoor air quality as expressed by the building occupants. At some point in time, the total concentration of airborne volatile organic compounds was proposed, as well. With the increasing accessibility and miniaturization of sensors, and with improved analytical methods, it is again becoming popular to measure concentrations of individual airborne pollutants and total concentration of groups of airborne pollutants as well as particular matter and use them as the index of indoor air quality. Yet, a few principal questions remain pending and the debate is ongoing as to what the premise should be for defining indoor air quality, which outcome/modality should be used for that purpose, and whether we can agree on a simple metric. It could be that such a single metric does not exist at all. At any rate, plausible approaches and schemes need to be considered and examined to ensure that indoor air does not compromise the basic human requirements, which include high quality of life, good health and optimal physical and mental activity. The measures proposed need additionally to ensure that full spectrum of pollutants is included to which human are exposed indoors, i.e. not only chemical pollutants but also particular matter and microorganisms. The plenary will briefly review indices used so far to define indoor air quality. It will discuss their strength, weaknesses and applicability as a metric for indoor air quality. Strategy for achieving high indoor air quality will be proposed and the necessary research objectives will be outlined to support it. The set of open questions to the audience towards the end of presentation will initiate further discussion on the topic that will continue during remaining day of the conference.

The green building industry uses leadership standards to define superior performance for individual projects and buildings. As a result, we have ample evidence that high performance green buildings represent superior real estate assets. Institutional investors have recognized this success, and they are now interested in the performance of entire real estate portfolios. GRESB provides institutional investors tools to assess, score, and compare portfolio-level performance. In this session, we will explore new GRESB data from over 750 property companies and funds with an aggregate asset value over $3 trillion USD. We will consider areas of relative strength and weakness in the adoption of IEQ-related practices around the world.