This paper investigates the concern that green buildings may promote energy efficiency and other as- pects of sustainability, but not necessarily the health and well-being of occupants through better indoor air quality (IAQ)。 We ask ten questions to explore IAQ challenges for green buildings as well as oppor- tunities to improve IAQ within green buildings and their programs。 Our focus is on IAQ, while recog- nizing that many factors influence human health and the healthfulness of a building。 We begin with an overview of green buildings, IAQ, and whether and how green building certifications address IAQ。 Next, we examine evidence on whether green buildings have better IAQ than comparable conventional buildings。 Then, we identify so-called green practices and green products that can have unintended and unfavorable effects on IAQ。 Looking ahead, we offer both immediate and longer-term actions, and a set of research questions, that can help green buildings to more effectively promote IAQ。 This article supports a growing recognition of the importance of IAQ in green buildings, and the opportunities for improve- ments。 As the World Green Building Council [95] and others have emphasized, people are the most valuable asset of organizations, and efforts to improve IAQ can improve health, well-being, productivity, and profitability。68737

1。 Ten questions

1。1。 What are green  buildings?

In general, “green buildings” are structures designed to promote efficient use of resources (e。g。, energy, water, and materials) and sustainability (e。g。 [93], and to reduce the adverse effects of buildings on the environment)。 A commonly cited definition of green building is provided by the US Environmental Protection Agency [28]: “Green building is the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction。”

In recent years, and more specifically, green buildings are typi- cally   defined   and   categorized   by   green   building  certification

* Corresponding author。 Department of Infrastructure Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010 Australia。

E-mail  addresses:  anne。steinemann@unimelb。edu。au   (A。   Steinemann),  paw@

byg。dtu。dk  (P。  Wargocki),  behzad。rismanchi@unimelb。edu。au  (B。 Rismanchi)。

programs。 Many countries around the world have their own pro- grams。 Early certification schemes include the Building Research Establishment Environmental Assessment Methodology (BREEAM) in the United Kingdom in 1990 [13], and Leadership in Energy and Environmental Design (LEED) in the United States in 1994 [83]。 Other major programs include the Deutsche Gesellschaft für nachhaltiges Bauen (DGNB) system in Germany [26], Comprehen- sive Assessment System for Built Environment Efficiency (CASBEE) in Japan [18], and the Green Star system in Australia [38]   [47]。

As of October 2016, over 145,000 green certification projects have been completed around the world, using these and other certification schemes [38]。 Globally, the percentage of firms with over 60% of their projects certified green is forecast to grow from 18%  in  2016  to  37%  by  2018,  with  a  greater  proportion    from

developing markets [89]。

Today, more than 31 green building certification programs   and

55 schemes within those programs (e。g。, for different types of buildings) are used in over 30 countries around the world, and some programs (such as BREEAM and LEED) are used in multiple countries [86]。 Other programs have emerged with goals to pro- mote  indoor air  quality and  occupant  health,  such  as  the  WELL