Ecologically and economically sustainable building has become more and more prominent in the last years. Just recently, I planned a trip to New York. Of course, while planning, I were on the website of the Empire State Building (ESB), one of New York’s most popular landmarks. There, I stumbled across the “Sustainability” tab. The headline reads “NEW YORK’S SUSTAINABILITY ICON.” “Sustainability” and the “Empire State Building”? How do these two terms go together?
The nearly 90-year-old Empire State Building has undergone a seminal energy and efficiency rehabilitation over the past 10 years as part of the rehabilitation program “Empire State ReBuilding” ($550 million). The building’s energy consumption has been significantly reduced and a large amount of energy costs have been saved in this way. The system infrastructure was redesigned from the point of view of optimal energy consumption. The elevators recover energy and the radiators reduce heat loss to the air with reflective barriers. The goal is the reduction of the carbon footprint. Most of the interior lighting has been renewed (adaptive dimming system that adjusts to the light coming in from outside and energy-efficient lamps). Each of the ESB’s 6500 windows was replaced, re-insulated and equipped with solar thermal protection to control the building’s temperature. In 2011, the ESB received “LEED® Gold for Existing Buildings” certification for this extensive renovation [1].
It is certified as a Green Building. A Green Building is a building whose construction is based on the use of ecological and sustainable building materials. Another important point of the Green Building concept is the energy supply. Energy consumption is kept as low as possible both during construction and operation and renewable energy sources are used. The building is managed sustainably. Drinking water is to be conserved as much as possible, and there are strategies for waste prevention. Modern building is based on holistic environmentally friendly concepts from planning to demolition [3].
There are several certifications for sustainable buildings. Among the best known are LEED (Leadership in Energy and Environmental Design) and BREAM. In each case, a building’s sustainability rating is based on several categories (see Fig. 2 for the categories of LEED certification). The categories of the various certifications are different to some extent, but the detailed requirements within the categories have many similar characteristics. Each requirement that is met in a building is awarded points. Points are awarded in all categories and added up after the evaluation is complete. The total score represents the sustainability of the building over its entire life cycle [6].
Do Green-Certified Buildings Have Better Indoor Air Quality? Without a doubt, it can be said that Green Buildings revolutionize the building industry. The Green Building concept focuses on minimizing energy and resource consumption as well as reducing environmental impacts. In addition, harmful effects on health are to be reduced and the quality of life and performance of the occupants are to be promoted. But is the Indoor Air Quality (IAQ) sufficiently taken into account in the certifications? After all, people spend an average of about 90 % of their time indoors. For this reason, it is especially important to pay attention to IAQ. It is necessary to ensure a high IAQ to guarantee the health of the occupants of buildings especially because air pollution is among the top 10 causes of mortality worldwide [5].
The paper “Indoor air quality requirements in green building certifications” [6] examined the extent to which IAQ is considered in green building certifications worldwide. IAQ requirements in 31 green building certifications from 30 countries worldwide were reviewed (13 countries in Asia, 9 in Europe, 5 in North and South America, 2 in Oceania, 1 in Africa). Some countries differentiate between building types (new building, existing buildings, residential buildings, non-residential buildings) for certification. This differentiation was taken into account by selecting 55 green building programs from the 31 certifications.
The result of the paper can be summarized as follows: IAQ is included in all of the certifications as a section that evaluates the health risk of indoor occupants. In percentage terms, the average contribution in green building programs worldwide is 7.5 %. The most commonly considered indoor air pollutants are volatile organic compounds (VOCs), formaldehyde, and carbon dioxide (CO2) (see Fig. 3). VOCs are considered in 84 % of certifications and CO2 is considered in 65 % of certifications. Ozone (O3) and semi-volatile organic compounds (SVOCs) are considered less frequently. These indoor air pollutants are considered for IAQ evaluation in only 6.7 % of certifications worldwide [6].
Another important finding is the different prioritization of indoor air pollutants on the continents (see Fig. 4). In America, for example, formaldehyde is given particular weighting. Formaldehyde is considered in 80 % of American certifications. In Europe, formaldehyde is only considered in 44 % of the certificates. VOC (TVOC), on the other hand, is taken into account more often in Europe, with a share of 44 %, than in Asia (it is only taken into account in 15 % of the certificates). Furthermore, ozone is not considered in Africa and Oceania and SVOCs are only considered in the CLIMATE certification in Austria [6].
In addition, this paper assesses IAQ management in the various certifications. In all certifications ventilation is included as an IAQ management option. Emission source control is included in 77 % of the certifications. This often targets emissions from building materials. Indoor air is measured in 65 % of all certifications [6].
How can the question “Do Green-Certified Buildings Have Better Indoor Air Quality?” be answered? The certification alone cannot be used to judge whether the Green Building has a better IAQ than a non-certified building. This can be illustrated by the following example: Green Buildings usually have a tight building envelope to achieve higher energy efficiency. However, the tight building envelope has the disadvantage of making it more difficult for indoor air pollutants to escape. The tight building envelope gets points for example in one of the LEED categories for energy efficiency. On the IAQ side, trade-offs are made or the tight building envelope must be compensated with appropriate IAQ management. Nevertheless, the total score is enough to certify the building as a Green Building.
It is positive that IAQ is taken into account in all green building certificates worldwide. However, the average weighting share in the certification is low (7.5 %) and the consideration of indoor air pollutants is not uniform (see prioritization of indoor air pollutants on different continents and frequency of indoor air pollutants in green building certifications worldwide). There is potential for improvement. It would be useful to pursue the idea of aligning all categories with the goal of uniform certification. As described previously, emission source control is included in a large proportion of certifications. But this mainly relates to emissions from building materials. The paper suggests that for existing buildings other emission sources should be given more consideration, such as emissions from cleaning agents and cleaning processes [6].
It is likely that IAQ will be increasingly considered in the future. Many furnishing and architectural firms already advertise natural and ecological interior products as well as sustainable furniture and home accessories. In this way, furniture and finishing products such as flooring and wall paints are not contaminated with pollutants that degrade IAQ. Returning to the Empire State Building. On the website is advertised with keywords like “No/low VOC materials only”, “No Red List materials allowed”, “MERV 13 filters” [1]. In this way, one is almost inclined to answer the question with yes after all.
References
[1] “New Yorks Symbol für Nachhaltigkeit.” Empire State Building, https://www.esbnyc.com/about/su stainability; Accessed 14 April 2022 [2] ventdusud. Getty Images/iStockphoto. “Empire State Building – Weltberühmter Wolkenkratzer in New York City”, USA Tipps, https://www.usatipps.de/wp-content/uploads/2018/06/empire-state-building. jpg. Accessed 15 April 2022. [3] “Green Building.” SKAPA, https://skapa-invest.de/glossar/green-building/. Accessed 15 April 2022. [4] “LEED for Homes Midrise: Now includes 8 stories in LEED v4.0”, Green Living, LLC, https://www.greenlivingllc.com/wp-content/uploads/2014/03/lfhcredits2.jpg. Accessed 15 April 2022. [5] Gakidou, E., et al. “GBD 2016 risk factors collaborators Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2016: A systematic analysis for the global burden of disease study 2016.” Lancet 390.10100 (2017): 1345-1422. [6] Wei, Wenjuan, Olivier Ramalho, and Corinne Mandin. “Indoor air quality requirements in green building certifications.” Building and Environment 92 (2015): 10-19.