The presumption that green products translate into good indoor air quality may be precarious。 Green products may not promote favorable indoor air quality for a number of reasons, among  them:

(1) Green certification standards may allow known hazardous compounds in products, (2) Green products are not required to disclose all ingredients, which can include hazardous air pollutants,

(3) Green product claims lack publicly available data for substan- tiation, (4) Green product guides, which list and sometimes rate green products, typically rely on disclosed information rather than independent product analyses, and (5) Green products used in buildings lack verification and monitoring of their emissions and effects on indoor air quality。

In conclusion, given that consumer products and building ma- terials are a primary contributor to indoor air pollution, truly green products and materials are essential to good IAQ。 However, prod- ucts marketed as green, and related attributes such as natural and organic, often lack scientific substantiation and justifiable criteria for their claims。

1。7。 What are implications of climate change for green buildings and IAQ?

Historically, research and attention on the links between climate change and air quality has focused overwhelmingly on the outdoor environment; for instance, the effects of increased temperatures on ground-level ozone。 Far less work has examined links between climate and the indoor environment, especially concerning IAQ。 However, recent years have seen a growing recognition of the importance of the effects of climate change, as well as extreme weather events on the indoor environment, which translate into considerations for green buildings。

The implications of climate change on IAQ are numerous and complex。 Some recent and notable studies (e。g。, [34,44,60,71]), have categorized and described these effects。 For instance, [60], explored the effects of climate change on factors that govern indoor pollut- ants: (a) properties of pollutants (e。g。, warmer temperatures affecting indoor pollutants from both indoor and outdoor sources),

(b) building factors (e。g。, reduced ventilation rate and increased air conditioning use), and (c) occupant behavior (e。g。, changes in hu- man activities and product use indoors) [34]。 examined (a) outdoor environment conditions that increase with climate change (e。g。, climate-related events such as heat waves, extreme precipitation, wildfires), (b) influences on indoor environment (e。g。, higher tem- peratures, dampness and mold, particulates and ozone, pollen al- lergies), (c) climate change adaptation (e。g。, increased use of air conditioning), and (d) climate change mitigation (e。g。, increased building energy efficiency)。 [71]; summarizing [44]; looked at (a) potential direct and indirect consequences of climate change (e。g。, increased incidence of extreme events, increased temperatures), and (b) potential impacts on the indoor environment (e。g。, changes in loads on HVAC systems, damage to and degradation of building materials, increased indoor ozone levels, flooding and water dam- age, greater use of pesticides) with potential impacts on health。 A full taxonomy of potential effects would be conceptually and practically difficult, not to mention nascent, since we may likely see effects not yet seen or predicted in our experience with climate and buildings。 Nonetheless, some key implications are described here。 Climate variables (e。g。, temperature, precipitation, water vapour, wind speed and direction, cloud properties) can influence indoor air quality both directly and indirectly。 For instance, increased outdoor temperatures can lead to increased ozone concentrations, and subsequent reactions that generate pollutants indoors。 Increased indoor temperatures can increase chemical off-gassing rates from indoor materials。 Increased precipitation can increase risk for flooding and water damage。 Climate change can also affect patterns of floods, droughts, wildfires, pests, and vegetation, and related indoor exposures to mold, dust, bacteria, combustion products, chemical pollutants, particulates, pesticides, and  pollen。