be applied … CDC encourages employees to be as fragrance-free as possible … Employees should avoid using scented detergents and fabric softeners on clothes worn to the office … ” and other mea- sures, which apply to more than 15,000 employees。 A recent survey of the US national population [74] indicated that a majority of the general population would prefer that workplaces, health care fa- cilities and professionals, hotels, and airplanes were fragrance-free。 Further, more than one-third of the general population reported adverse health effects, such as migraine headaches or asthma at- tacks, from exposure to fragranced products, indicating the magnitude of potential benefits from a fragrance-free policy。

Another action to promote IAQ in green buildings would be the requirement of indoor air quality guidelines or threshold concen- trations for pollutants of concern。 For example, the World Health Organization (WHO) issues guidelines for air quality, some of which are regularly updated [90e92]。 These guidelines or other well- documented and recognized references could become a funda- mental element in certification schemes。 Another approach would be the development of standards for IAQ in green buildings, taking into consideration health guidelines for exposure to  pollutants。

Additional strategies for source reduction and control include the following: use alternative pest management, such as physical controls without chemical pesticides; implement a healthier cleaning program, as well as nonchemical methods for cleaning; switch to low off-gassing furnishings and materials; install appro- priate air filters, which may be common, but also water filters to reduce exposure to volatilized compounds; maintain HVAC sys- tems, including filter check and replacement; and require more frequent monitoring of indoor air quality and surveys of occupant well-being。

In conclusion, given that products and practices indoors are a primary influence on IAQ, actions that target those areas can pro- vide a relatively straightforward way to improve and monitor IAQ。 A focus should be on overall exposure reduction, such as source reduction and control, rather than solely  ventilation。

1。9。 Longer term, how can green buildings be improved to promote better IAQ?

A range of actions can enable certification schemes to more effectively promote IAQ in green buildings。 One development would be the definition of an index or metrics of IAQ in buildings。 Without discussing whether the development of such an index is at all possible, it is worth mentioning that the lack of such an index is a reason why ventilation, and CO2 concentration (a proxy for ventilation effectiveness in the presence of people), are used to assess IAQ。 It is also worth mentioning that there were attempts to develop such an index in the past。 For examples, the levels of dissatisfaction with acceptability of indoor air quality as expressed by the building occupants [33] as well as total volatile organic compounds (TVOC) [59,68] were proposed as metrics of IAQ, among others。 However, the TVOC was shown to be a poor pre- dictor of the effects on humans [5]。 The former approach still cre- ates the reference for estimating ventilation requirements for achieving acceptable indoor air quality [8,27]。 Despite these at- tempts, developments of IAQ metrics can continue, and could address not only pollutant levels and exposures, but also their ef- fects on building occupants。

In addition, to properly manage and characterize IAQ in green buildings, it may also be beneficial to require emissions testing of all building materials, furnishings and equipment both before and during their use in green buildings。 To this end, green  buildings may require regular or even continuous measurements of IAQ。 Such monitoring would allow remedying unacceptable pollutant levels and sources as well as provide data for building recertification。 IAQ