Towards the integration of air chemistry and building simulation models IAQ assessment

Abstract

To limit greenhouse gas emissions, energy efficiency measures are applied at a large scale resulting in buildings becoming more airtight. Indoor environmental quality depends strongly on ventilation rates. Whilst controlled ventilation contributes to the reduced use of fossil fuel, too little ventilation increases the risk of health-damaging concentrations of pollutants in the indoor environment. There are three primary sources for pollutants indoors (1) ventilated outside air, (2) emissions from activities such as cooking and cleaning and (3) longitudinally emitted pollutants from people, building components and furnishings. Some accepted primary pollutants to assess indoor air quality are CO2, Volatile Organic Compounds (VOC) and OH. However, indoor chemistry studies indicate the presence of a great amount of complementary secondary pollutants with potentially health-damaging effects. Secondary pollutants indoors are the result of chemical reactions of pollutants with solar radiation as an energy source and ozone/other oxidants. Little is known about the type of resultant secondary pollutants and their effect on human health. One approach to assess the effect of secondary pollutants on indoor environmental quality is to integrate chemical box models with building simulation models, e.g. computational fluid dynamics. In this contribution, the authors provide an overview of the state of the art in integrated simulation models of air chemistry with building performance. A reduced-order case study will be presented comparing methods and identifying key parameters for indoor air quality, including selected secondary pollutants. Additionally, a conceptual framework is presented for assessing the impact of secondary pollutants on human health.