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Measuring indoor air quality

Indoor Environmental Quality

Improving the indoor environmental quality
Through research in both lab and field settings we are defining optimal indoor environmental conditions from the occupants' perspectives, using a suite of architectural scientific methods.

The mission of our research in indoor environmental quality is to improve the quality of internal environments in buildings where we spend more than 90 percent of our day-to-day lives. We aim to define the relationships between building occupants – including their comfort, health, wellbeing and productivity – and the physical characteristics of the indoor environments they occupy.


Our specific focus is on thermal, acoustic and lighting comforts, along with indoor air quality. We produce occupant-centred, evidence-based design guidance that is relevant to both the design-stage and operational-phase of a building’s lifecycle.

We use field and lab research methods, and in both cases we apply objective (instruments and sensors) as well as subjective measures (questionnaires, interviews, focus groups) in a stimulus-response research design.

Using lab methods allows for precise control of experimental subject exposures to indoor environmental qualities such as temperature, humidity, air movement, ventilation rates, and pollution concentrations, daylight, artificial lighting, sound pressure level, and other acoustic qualities. Field methods on the other hand, use actual buildings with ‘real’ occupants (cf experimental subjects). The advantage of field methods is that they produce new knowledge with greater external validity and generalisability than is possible with lab methods. The IEQ Lab often combines both lab and field methods to ensure internal and external validity of the research. 

Our research falls into the broad categories of architecture and engineering. To date, most knowledge in the domain of IEQ has come from engineering, with a focus on the elimination or management of discomforts, health hazards and productivity constraints of buildings. However, we also use an architectural approach to our research by focusing on passive and low-energy design strategies that are more sympathetic to external environmental and climatic contexts.

Recent and ongoing funded research

Funding source: 2016-18, Australian Research Council (ARC) DP DP160103978

Researchers: Professor Richard de Dear, Dr Densil Cabrera, Dr Jungsoo Kim

Without internal walls, open-plan offices are designed to make people interact more frequently and therefore be more collaborative and productive. Yet there is a high level of dissatisfaction with the open-plan layout because of frequent distraction by background speech from co-workers, which has been shown to significantly decrease work performance and productivity. This project aims to better understand how irrelevant speech in open-plan offices affects the occupants’ cognitive performance and creates annoyance. The intended outcomes are the development of powerful new tools to measure, model and predict the degree of speech distraction at work, enabling establishment of new international standards.

Funding source: 2012-14, National Research Foundation of Korea

Researchers: Professor Richard de Dear (University of Sydney), Professor Chungyoon Chun (Yonsei University), Professor Ed Arens (UC Berkeley)

Funding source: 2011-14, Australian Research Council (ARC) Linkage LP110200328

Industry partners: Arup, Brookfield Multiplex, The GPT Group, Investa Property Group, Stockland Property Management.

Researchers: Professor Richard de Dear (University of Sydney), Dr Christhina Candido (University of Sydney), Mr Craig Roussac, Dr Jungsoo Kim (University of Sydney), Dr Thomas Parkinson (University of Sydney), Ms Leena Thomas (UTS)

In-kind support: National Australian Built Environment Rating System (NABERS)

Post Occupancy Evaluation (POE) generates feedback on the performance of buildings from their occupants’ perspectives. As an indoor environmental quality assurance process, POE accelerates diffusion of best design practices and minimises bad design recidivism. The Building Occupants Survey System for Australia - BOSSA - will be a POE system for Australia’s office buildings. As the BOSSA database grows with each additional building surveyed during this project, it will underpin an ongoing program of architectural science research aimed at improving occupant health, comfort and productivity outcomes from sustainable office buildings.

Funding source: 2011-16, Ministry of New and Renewable Energy, Government of India, Climate Works Foundation and Shakti Sustainable Energy Foundation

Researchers: Professor Richard de Dear (University of Sydney), Ms Leena Thomas (UTS), Professor Rajan Rawal (CEPT University)

Researchers: Professor Richard de Dear, Dr Christhina Candido, Dr Jungsoo Kim, Dr Max Deuble

Adaptive comfort standards have two broad applications; they are widely used in the design phase to assess feasibility of natural ventilation. This can be done with simplified assessment tools, including software, at the earliest design phase, or later in the design phase with the aid of dynamic thermal simulation software, based on input of TMY weather data. The second major area of application for the adaptive model – compliance checking of extant buildings – is less well documented.

This paper describes a Thermal Comfort Policy being developed for a client who owns a large portfolio of buildings in Australia. To date the client’s decisions about where and when to install HVAC have been based on an isotherm on the climate map of the region in which they operate. Buildings located north (ie, warm-side) of the 33 degrees Celsius mean daily maximum January (Austral summer) isotherm are air-conditioned by default, regardless of how well the building performs in that climate zone. Buildings falling on the south side of the 33 degrees Celsius January mean daily maximum isotherm do not receive air conditioning, even if their thermal performance is demonstrably poor.

The client’s project brief aims to shift those air conditioning decisions onto a more rational footing, based on the climatic context, the building’s thermal performance, and the building occupants’ thermal comfort requirements. The ASHRAE 55-2010R adaptive model is being used as the basis for the human comfort criteria with an exponentially-weighted running mean outdoor temperature for input. Two metrics have been proposed for the diagnosis of overheating;

a) percentage of occupied hours during which indoor operative temperature exceeds the ASHRAE 55 upper limit (80 percent acceptability), and

b) cumulated degree-hours based on an indoor operative temperature baseline of the ASHRAE 55 upper limit (80 percent acceptability).

Our researchers