Climate change mitigation and adaptation measures can also affect indoor air quality。 For instance, measures to reduce energy use can lead to lower ventilation rates, tighter buildings, increased reliance on air conditioning, and less use of open windows, which can increase pollutant concentrations indoors。 Climate-related hazards can drive people to spend more time indoors, which can potentially increase indoor pollutants, such as through increased indoor activities and product uses that generate  pollutants。

While climate change has effects on many types of buildings, especially relevant to green buildings are effects related to energy efficiency measures。 These include tighter buildings, weatheriza- tion, and less use of natural ventilation。 As indicated by Ref。 [60]; perhaps more important than the effects directly from climate are the effects that are mediated by humans in response to climate changes。 A major effect is reduced ventilation rates due to mitiga- tion measures to save energy, and greater reliance on heating, ventilation, and air conditioning systems, and less reliance on open windows。 While reduced ventilation can reduce infiltration of pollutants from outdoors to the indoors, it can also increase con- centrations of pollutants indoors。 The importance of reducing sources of indoor emissions is even more  pronounced。

In conclusion, climate change can create specific challenges for green buildings through increased demands for energy efficiency, combined with changes in outdoor air pollutants, extreme weather events, and mitigation and adaptation measures that can affect IAQ。

1。8。 What immediate actions could promote higher IAQ in green buildings?

While it may be thought that indoor air quality problems are ineluctable, to the contrary, some immediate actions can improve indoor air quality。 The net benefits of specific actions depend of course on the specific building and the sources of pollutants。 Also, any action can have a range of effects, and the direct and indirect implications need to be considered before implementing measures。 While the literature abounds with recommendations for improving indoor air quality (e。g,。 [66,72,73], this section discusses some ac- tions that can be introduced at once, are likely to provide overall beneficial effects, and that may not already be included in green building schemes。

One important action would be to focus on pollutant exposure reduction in buildings。 Currently, all schemes award ventilation as the major method related to indoor air quality, while exposure receives relatively little attention。 Ventilation, although important, may not always provide the desired effects, such as in areas with high outdoor pollution or episodic and uncontrolled release of pollutants (e。g。 Ref。 [17]。 Ventilation may not be effective either for some pollutants, such as SVOCs [58]。 Therefore, green building schemes that provide credits only for ventilation may not ensure favorable IAQ。 Instead, with a focus on exposures, including actions for source control and reduction, green building schemes could encourage effective methods for reducing risks to human health, which is a goal of improving  IAQ。

Another immediate action that could produce benefits would be to reduce compounds that are among the most prevalent and dominant of indoor air pollutants (e。g。, [19,20,39,50]; namely, fragrance compounds emitted from products。 Fragrance-free pol- icies, which restrict the use of fragranced products, have been implemented in building environments around the world, such as schools, workplaces, hospitals, and public buildings。 For example, the US Centers for Disease Control and Prevention, Indoor Envi- ronmental Quality Policy [84] states: “Scented or fragranced products are prohibited at all times in all interior space owned, rented, or leased by CDC … Personal care products (e。g。 colognes, perfumes, essential oils, scented skin and hair products) should not