Similar to “green” buildings, the concept of “green” products has

no universal or standard definition。 Even though some products are marketed as being green, the term does not guarantee healthier products or better IAQ。 Recent research has found that products with claims and certifications of green (e。g。, green cleaning prod- ucts, building materials, and furnishings), can nonetheless emit and generate hazardous compounds, and sometimes comparable to their conventional counterparts (e。g。, [67,75]。

So-called green, natural or organic products or materials can nonetheless contain or generate hazardous constituents。 For example, green cleaning products often contain fragrance chem- icals (e。g。, terpenes) that are primary pollutants, and that react with ozone to generate a range of secondary pollutants such as formal- dehyde and ultrafine particles [61]。 A comparative analysis of vol- atile emissions from green and conventional fragranced products, including cleaning products and air fresheners [75], found over 550 VOCs emitted from 37 products, with nearly 25% classified as toxic or hazardous under US federal laws。 However, fewer than 3% of emitted ingredients were disclosed on product labels or material safety data sheets。 Emissions of carcinogenic hazardous air pol- lutants from green fragranced products were not significantly different from conventional fragranced products。 Fundamentally, if the product contained fragrance, regardless of nomenclature (e。g。, green, organic, essential oils, or all-natural) it emitted potentially hazardous air pollutants。 Yet nearly all green cleaning product certifications and standards permit the inclusion of  fragrances。

As another example, even zero- or low-VOC paints, including ones certified as green, can still emit VOCs similar to regular paints, as well as other problematic chemicals such as SVOCs。 In tests of various green certified and conventional paints [67], no significant difference in emissions was found between conventional paints and the low-VOC and zero-VOC paints, and the ultra-low VOC paints showed the highest emission potential。 The tested products emitted almost the same spectrum of substances independent of certification marks。 Also, some green building materials such as linoleum contain linseed oil, which can release VOCs  that react with ozone to generate aldehydes [63];  [45]。

In addition to VOCs, green products can also contain and emit a range of other potentially hazardous compounds; these include SVOCs (e。g。, phthalates), plasticizers, antimicrobials, and a range of asthma-associated and endocrine disrupting compounds [36,75]。 Indoor air quality is heavily influenced by the vast array of com- pounds emitted and generated from consumer products and building materials, and many types of compounds found indoors today were not present a half-century ago  [88]。

While numerous organizations and agencies have developed labeling programs for green products, and companies are market- ing their products as green, the term is generally unregulated and undefined。 Greenwashing, or making misleading or unsubstanti- ated claims about the environmental benefits of a product, is a well- recognized problem, likely fueled by demand for green buildings and products。 Over 500 green certification labels exist in the US alone [24]。 A study of nearly 400 green cleaning products in the US and Canada, which collectively made over 1200 green-related claims, found that fewer than 1% of the products made no misleading or unsubstantiated claims  [82]。

Indeed, green product claims and potential benefits are difficult to verify。 Unlike other commodities, building materials and con- sumer products, even ones called green, are not required to disclose all product ingredients on the label, material safety data sheet, or elsewhere to the public [76]。 Also, green product rating guides typically rely on only listed or disclosed ingredients, which can represent just a small percentage of actual ingredients  [75]。