What This project is about identifying important chemical processes responsible for poor air quality in our indoor environments. The project will examine how abundant chemical pollutants directly emitted from indoor source such as building materials and furnishing may undergo chemical reactions in the indoor air and on surfaces. Such reactions are hypothesized to result in in the transformation of relatively benign indoor pollutants into ones that have adverse health outcomes; an until now understudied source of bad indoor air quality. The project will furthermore examine how indoor chemistry is affected by the intrusion of outdoor air and how rising air pollution in urban areas may change our exposure to organic pollutants in our homes, offices, schools and institutions. Why Humans spend 90% of their time indoors; consequently, human exposure to most air pollutants is actually dominated by indoor rather than outdoor conditions. Recent research has shown that the air within our homes can be more heavily polluted by organic chemicals than the outdoor air. The suspected reactivity of these chemicals in combination with the large surface areas of the indoor environments makes for a potent chemical reactor, especially when considering the unavoidable intrusion of reactive species from rising outdoor air pollution. This project is important as it provides new insight into the sources of bad indoor air quality and thus may aid in the development of more intelligent solution to improve the quality of the air we breathe and consequentially our health and well-being. How The research will be based on detailed chemical analysis of air and surfaces in real and laboratory-controlled indoor environments. Emissions and chemical reactions of commonly found indoor pollutants will be studied along with the impacts of changing indoor parameters, e.g. temperature, light, humidity and ventilation. The formation of airborne and surface-bound pollutants from indoor chemical processes will be investigated in environments such as class rooms, offices, and homes. In addition, indoor chemistry facilitated by increased intake of outdoor air pollution will be simulated in real indoor environments and in the laboratory to understand the risks associated with inadvertent intrusion or deliberate ventilation with polluted outdoor air. SSR The time we humans spend indoors is increasing drastically. Our work and daily lives now predominately takes place inside where global warming and rising outdoor air pollution is motivating us to better isolate ourselves from the outdoors. Consequently, poor indoor air quality (iaq) is now a global threat to human health and there is an urgent societal need for improving iaq in Denmark and worldwide. This project will provide a deeper understanding of what courses poor iaq which is a first step to answering this unmet need, as this is a prerequisite for the development of healthier homes and new clean air solutions, which can effectively mitigate poor iaq thus ensuring, that the time we spend indoors is not diminishing our health and well-being at great cost to the individual and society.