Comparison of Health and Well-Being Aspects in Building Certification Schemes

The quality of the indoor environment is becoming increasingly important because people are spending the majority of their time indoors. This has led to an increased interest in the field of health and well-being of users of buildings and to the development of various assessment schemes dealing with this issue. In this study, LEED O+M Building Operations and Maintenance (hereinafter LEED O+M), BREEAM In-Use and DGNB Buildings In-Use were compared with a specialized BCS WELL that is focused on the health and well-being of building occupants. The aim of the comparison was to evaluate to what extent the selected building certification schemes (BCSs) cover the aspects of health and well-being in buildings. Based on the analysis, it was found that the observed BCSs mostly pay attention to indoor air quality, light and thermal comfort. In other areas, only certain topics are covered or the topics have a different focus. Another important finding of the study was that certain aspects that are important for the health and well-being of the occupants are not dependent only on the building design but also on the management of the building and the services provided within the building. This kind of information is especially valuable for building developers, managers and owners so they know how to improve health and well-being in a building. The present study provides them with a comprehensive overview of the certification schemes that are widely used in current practice.


Introduction
We are spending the majority of our time indoors and consequently the indoor environment is becoming increasingly important. Different studies emphasise that the indoor environment can affect human health. A connection between key public health concerns of the modern society, such as asthma, cancer, and obesity, and indoor building conditions has been recognised [1]. Exposure to various health risks in the indoor environment results in the occurrence of Sick Building Syndrome (SBS) or Building-Related Illnesses (BRI). SBS is described as a situation in which building occupants experience acute health and comfort effects that appear to be linked to the time spent in the building, although no specific illness or cause can be identified [2,3]. The complaints are sometimes localised to a particular room or may be spread through the whole building. The symptoms associated with SBS are headache, irritation of the eyes, nose or throat, dry cough, dry or itchy skin, dizziness and nausea, difficulty concentrating, fatigue, and sensitivity to odours [3]. In contrast, the term Building-Related Illness (BRI) is used when symptoms of a diagnosable illness are identified and can be attributed directly to airborne building contaminants [2].
The main objective of this review is to analyse which topics related to health and well-being of the occupants are represented in specific BCSs that deal with the sustainability of already constructed buildings, what the topics are specifically referring to and to what extent they are processed. The review was conducted as a comparison of schemes derived as subsidiary schemes from most common sustainability BCSs with BCS WELL, in such a way that WELL serves as a reference BCS. It shows where the potential is of the chosen BCSs in terms of their improvement of particular topics and consequently it provides valuable information for the development of the compared BCSs. Finally, it also helps investors to decide whether they want to perform supplementary certification that evaluates the existing building according to the health and well-being of the occupants, or not.

Methodology
In the study, the three most commonly used sustainability BCSs for buildings-LEED O+M Building Operations and Maintenance (hereinafter LEED O+M) [22], BREEAM In-Use [23] und DGNB Buildings In-Use [24]-are compared with the specialised BCS WELL by using the structure of its main areas that is proposed in the certification system WELL. We have chosen the BCS on the basis of a market study for the European Commission. The defined leading sustainability BCSs for Europe are BREEAM, LEED, DGNB and HQE [25]. According to the study, BREEAM has the largest market share (80.6%), followed by HQE (11.3%), DGNB (4.4%) and LEED (3.4%). Because the HQE is mainly focused on the French market while other BCSs are used internationally, we have focused the study on the LEED, BREEAM and DGNB rating systems. These are also the rating systems that have been assessed in the study by Bernardi et al. and are claimed to be the most used rating systems for assessing the environmental impact of buildings [26]. They have been compared with the WELL certification system specialised in health and well-being that is also present in the European market [27]. Because WELL assesses already-constructed buildings, we have compared it with the sustainability BCSs versions that also focus on already constructed buildings, namely LEED O+M, BREEAM In-Use und DGNB Buildings In-Use.
The structure of the areas that are compared in the study is derived from the WELL: air, water, light, nourishment, fitness, comfort and mind. These areas are further divided into topics. The great majority of data used for the comparison was acquired directly from the official technical manuals of the BCSs. We have not applied the selected rating systems in the paper. The analysis focuses on the comparison of the officially declared topics of the certification systems.
Firstly, we present the health aspects assessed in the study in Section 2.2. Secondly, in Section 2.3 we compare the selected areas based on the topics they assess, the standards they build on and the benchmarks they are setting. The topics were divided into those that are dependent on the management of the building and those dependent on the building design. The topics related to the building design are identified by bold print in the tables.

Health Aspects Assessed in the Study
This chapter describes the relation between the indoor building environment and the occupants' health and well-being in the selected areas. The division into areas dictated how this and the following chapter are structured.

Air
The indoor air quality (IAQ) influences the health of the occupants significantly, especially since people of developed countries in temperate climate regions spend most of their time indoors [28]. The World Health Organization (WHO) has published a study in which it is estimated that 1.6 million excess deaths are associated with exposure to indoor air pollutants. [29]. The pollutants are mainly fine particles, carbon monoxide, polyclinic aromatic hydrocarbons, nitrogen dioxides, sulphur oxides, arsenic and fluorine, volatile and semi-volatile organic compounds, aldehydes, pesticides, asbestos, leas, biological pollutants, radon, free chemicals, etc. [28]. The hypothesis that exposure to air pollution increases the risk of developing various illnesses, such as cardiovascular or respiratory diseases, has been demonstrated in a number of studies [30]. In recent research by Wei et al. [31] it was found that the average share of the evaluated IAQ in the total rating of individual certification schemes surveyed was 7.5%. However, in American BCSs, the emphasis on IAQ is considerably higher.

Water
Providing access to drinking water is an important aspect of health in buildings. Different legislation and policies worldwide have been developed to ensure the safety of drinking water in the built environment with an approach that ensures systematic assessment of risks over the entire water cycle, from catchment to the consumer. The WHO has developed strategies for managing drinking water during everyday consumption. The document includes supporting information about microbial, chemical, radiological and other acceptability aspects. It also deals with water quality and management inside buildings [32]. In the current research there is a lot of emphasis on efficient water use [33,34] and less on water quality.

Nourishment
Nourishment is a specific area covering food or other substances necessary for growth, health, and good condition. Today the benefits of healthy and wholesome nutrition are fully recognised and are part of the basic requirements for healthy living [35]. Access to healthy food is determined by the location of the building and what is available in the building [36]. Another possibility is to grow the food inside the building, such as in the form of vertical farming or rooftop gardening [37].

Light
The indoor space is an artificial environment with restricted access to daylight. It is generally known that light affects the physical, physiological and psychological condition of people. Installing artificial lightning devices light cannot completely compensate all the positive aspects of daylight. Webb [38] states that any kind of light suitable from the visual aspect does not necessarily cover non-visual needs such as the influence on the occupant's sleeping patterns, daily hormone secretion patterns, the body's temperature cycles, etc. The study by Bellia et al. [39] confirms that unsuitable light conditions influence the performance, safety and health of the occupants. Their non-visual characteristics influence the occupants' circadian rhythm. In their study, Galasiu and Vietch [40] stated that people have a strong preference for daylight in buildings, especially in office buildings. Moreover, if the windows provide a nice view of the outside, the glare from the sky is not so distracting.

Fitness
Research performed by the WHO [41] identified physical inactivity as one of the leading risk factors for global mortality and it consequently published recommendations for how to increase physical activity, called The Global Recommendations on Physical Activity for Health. The role of buildings in a built environment is significant, as their design can greatly contribute to the promotion of human physical activity. For example, a study conducted by Bullock et al. [42] showed that bike-sharing schemes had several benefits, like journey time savings, health benefits and reductions in motor vehicle use or similar, and the use of bikes could be easily promoted by building design. The proximity of green spaces can also increase the physical activity of the occupants [43]. Another possibility is the promotion of walking inside the building, integration of active furnishing, incentives encouraging greater levels of physical activity, etc.

Comfort
Buildings have to ensure a comfortable living and working environment. Not only the acoustic, thermal, ergonomic and olfactory comfort, but also the physical and psychological comfort are crucial to prevent stress and may help to increase the productivity of the occupants. However, the current studies mainly focus on thermal and acoustic comfort [43][44][45]; ergonomic and olfactory comfort are rarely discussed.

Mind
The area Mind involves human mood or mental state at a particular time and situation. The state of mind and human physical health are inextricably connected. Each environment that is able to support a healthy mental state can offer significant psychological and also physical benefits for the occupants [43]. The building design plays a significant role in this area. For instance, it impacts the mood and the quality of sleep, and in this manner affects the stress levels [46].

Comparison of Different Areas
The majority of topics assessed in the WELL scheme are partly covered in other BCSs compared in this study. For instance, the LEED O+M covers topics connected to air quality, water quality, visual comfort and overall comfort, mostly related to thermal and acoustic comfort. BREEAM In-Use covers a similar set. DGNB Buildings In-Use additionally covers some aspects of the area Mind, assessing parameters influencing the mental state of the occupants, but it does not cover areas like Water, Nourishment, Light or Comfort. Figure 1 illustrates the coverage of topics with respect to the BCS in a certain area. Although this gives us some basic information about how many topics a particular BCS is actually dealing with, the topics in each BCS are covered to a different extent.

Comfort
Buildings have to ensure a comfortable living and working environment. Not only the acoustic, thermal, ergonomic and olfactory comfort, but also the physical and psychological comfort are crucial to prevent stress and may help to increase the productivity of the occupants. However, the current studies mainly focus on thermal and acoustic comfort [43][44][45]; ergonomic and olfactory comfort are rarely discussed.

Mind
The area Mind involves human mood or mental state at a particular time and situation. The state of mind and human physical health are inextricably connected. Each environment that is able to support a healthy mental state can offer significant psychological and also physical benefits for the occupants [43]. The building design plays a significant role in this area. For instance, it impacts the mood and the quality of sleep, and in this manner affects the stress levels [46].

Comparison of Different Areas
The majority of topics assessed in the WELL scheme are partly covered in other BCSs compared in this study. For instance, the LEED O+M covers topics connected to air quality, water quality, visual comfort and overall comfort, mostly related to thermal and acoustic comfort. BREEAM In-Use covers a similar set. DGNB Buildings In-Use additionally covers some aspects of the area Mind, assessing parameters influencing the mental state of the occupants, but it does not cover areas like Water, Nourishment, Light or Comfort. Figure 1 illustrates the coverage of topics with respect to the BCS in a certain area. Although this gives us some basic information about how many topics a particular BCS is actually dealing with, the topics in each BCS are covered to a different extent.  A lot of topics related to the health and well-being of the occupants are not directly dependent on the design of the building, but are more relevant to the management of the building and services provided within the building. To be distinguished they are marked with two colors in Figure 1. The topics air quality, water quality and topics from the areas Nourishment and Mind are predominantly related to the management of buildings. The topics from the areas Light, Fitness and Comfort are mainly dependent on or influenced by the building design.
A comparison of the studied BCSs for each of the selected area follows.

Air
Indoor air quality (IAQ) is assessed in all studied certification schemes. However, the BCS DGNB In-Use does not directly address this topic. The other three BCSs compared, BREEAM In-Use, LEED O+M and WELL, provide more direct requirements for the quality of air inside the building. The WELL provides exact numerical benchmarks, while the other two either refer to standards (LEED O+M) or give advice on monitoring the air quality (BREEAM In-Use and LEED O+M). Volatile organic compounds (VOCs) as well as the ventilation rates are addressed in all three BCSs except DGNB Buildings In-Use. A great advantage of WELL over other BCSs is that it covers several additional topics like microbe and mould control, pesticide management and construction pollution management, healthy entrance, cleaning protocol, fundamental material safety, and moisture management. These topics are mostly neglected by other BCS.
WELL and LEED O+M additionally refer to national or international standards, like the ASHRAE Standard or CEN Standards, while BREEAM In-Use and DGNB Buildings In-Use do not refer to any of them. WELL mentions the ASHRAE standard, while LEED O+M offers the possibility to choose other standards as well, making it easier to apply internationally. In addition, WELL gives exact benchmarks, while in other BCSs no benchmarks are given. The results of the analysis are presented in Table 1.

Water
Among the compared certification systems, only BREEAM In-Use and WELL include a chapter about the quality of drinking water that is directly related to the health of the occupants ( Table 2). The WELL certification system evaluates the quality of drinking water, especially its possible contamination with inorganic, organic or agricultural releases. It gives strict benchmarks for water quality that are necessary to obtain the evaluation credits. The certification scheme proposes periodic testing of water quality and encourages the use of diverse water treatment procedures. Moreover, WELL evaluates the promotion of using drinking water inside a building. BREEAM In-Use also encourages the promotion of drinking water for the occupants. Credits are also given for ensuring water safety through legionella management and for the development of a water-quality management strategy.
Neither WELL nor BREEAM In-Use has a legislative background concerning the quality of water. The benchmarks that can be used for the evaluation to certify the quality of the water in the building were developed exclusively within BCS WELL.

Nourishment
Nourishment is covered only by the WELL building certification scheme, which specifically focuses on the health and well-being of the occupants. The scheme evaluates whether food provided either in vending machines or in restaurants is fresh and wholesome. Additionally, it proposes limiting some food ingredients that are not considered healthy. Promotion of healthy eating habits and raising awareness about unhealthy food are also rewarded. Besides the food provided inside the building, the certification scheme also evaluates the access to farmers markets, the proximity of other stores offering healthy and fresh food, and the promotion of consumption of fruit and vegetables. A few assessment topics of this area are actually directly related to the building itself, and not to services provided in the building or the location of the building. These are on-site food production, provision of areas for eating and proximity to farmers markets or food stores. The results are presented in Table 3.

Light
According to our review, all the building certification schemes studied deal with the evaluation of the influence of light in the building on the well-being of the occupants, except DGNB Buildings In-Use. Topics that are assessed in the studied BCSs are presented in Table 4. The WELL evaluates natural and artificial lightning, the prevention of glare as well as colour quality and surface design. The occupant's visual connection with the exterior is also included. WELL also gives credits for an optimal window-to-wall ratio that is determined in the WELL BCS and the visibility parameters for lights are also set. The LEED O+M provides the strictest requirements not only for interior lighting but also for providing daylight to the indoor environment and appropriate visual connections to the exterior. BREEAM In-Use focuses on glazing ratios of the façade, the prevention of glare, and adequate illuminance levels and control of artificial lighting.
The only BCS referring to the standards in this particular area is BREEAM In-Use. It declares that for the assessment of the credits EN standards should be used. This is additional proof that BREEAM In-Use is focused on the European market.
The benchmarks for acquiring the credits in the certification process are given in two BCSs, WELL and LEED O+M. It is worth mentioning that the benchmarks are quite strict and even comparable between both systems, since they refer to the same standards.

Fitness
One would expect the BCSs under consideration to tackle the topics dealing with the physical activities of the occupants in buildings as well. However, with the exception of WELL, none of them addresses this issue directly. Instead, by addressing specific topics they promote good bicycle access or alternative means of transport to the building (LEED O+M, BREEAM In-Use and DGNB Buildings In-Use). These topics are associated mainly with the location of buildings and their design. Again, WELL is quite the opposite, as it includes eight topics related to physical activity in the building (Table 5), yet with no direct standards or benchmarks. WELL, LEED O+M and BREEAM In-Use all evaluate thermal comfort within the buildings. Acoustic comfort is covered by WELL and BREEAM In-Use. In comparison with BREEAM In-Use, which only assesses whether the building has been evaluated by an appropriate expert, WELL gives more precise acoustic requirements. BREEAM In-Use additionally covers the comfort related to the ventilation in the building. WELL has precise requirements about ergonomics for the occupants, the olfactory comfort and provision of adequate measures for disabled people.
LEED O+M and WELL use ASHRAE standards that should be fulfilled in order to achieve credit for the thermal comfort. WELL additionally requires the use of ADA Standards for accessible design and HFES 100 standard for chair ergonomics.
Nevertheless, the only BCS that uses exact benchmarks is the WELL methodology. The results are shown in Table 6.

Mind
The topics assessed in the area Mind are related partly to the services provided in the building and partly to the building design. Topics related to the building design are the adaptability of spaces, as evaluated by WELL and BREEAM In-Use, the inclusion of nature in the design, the assurance of safety by different alarm systems, etc. On the other hand, the area Mind assesses a lot of aspects that are actually services for the occupants. For example, WELL, BREEAM In-Use and LEED O+M all give credits for conducting surveys about the satisfaction of the building's occupants (Table 7). These surveys cover different topics related to various issues of comfort and offer the possibility for the occupants to express their opinion and will. Additionally, WELL and BREEAM In-use promote health and wellness awareness of the building's occupants. None of the BCSs studied provide standards or benchmarks that should be followed to obtain the credits.

Discussion
The construction industry uses certification schemes to evaluate the performance of buildings, including their effect on the health and well-being of the occupants. However, BCSs evaluate topics connected to health and well-being differently. An overview of the content of the studied BCSs is presented in Table 8. Table 8. An overview of the content of the studied BCSs.

Topic WELL [18] LEED O+M [22] BREEAM In-Use [23] DGNB BUILDINGS In-Use [24]
Air For example, the topics connected to the area Air are covered to a great extent in all of the studied BCSs except DGNB In-Use. DGNB In-Use should be improved to be comparable with other BCS that deal with buildings in use since other schemes already pay a lot of attention to this area.
In the area Water, the studied BCSs should target the quality of the water inside the building more to ensure that the occupants have access to clean and healthy water. This means they should focus on the water system management and ensure that the water inside the building is drinkable, instead of dealing only with reduced water use.
Most topics in the area Nourishment are related to food provision services in buildings and are therefore predominantly appropriate for evaluation of buildings where food is served. Consequently, they are completely neglected by all BCSs under consideration, except WELL. In our opinion, the area Nourishment is very specific and most countries already have national standards covering this issue. Therefore, there is no need to include it in sustainability BCSs.
Furthermore, the area Light is well addressed by all of the compared BCSs except DGNB In-Use; the topics are mostly covered by standards and benchmarks. This suggests that the authors of these BCSs are already aware of the importance of visual comfort for the well-being of the occupants.
Fitness is addressed in all of the studied schemes but the topics deal predominantly with fitness linked to transport to and from the building. They do not provide opportunities for actual physical activities for the occupants inside the building.
Then there is the area Comfort in buildings, which is addressed by the studied schemes in various ways. Thermal comfort is addressed in all of the studied BCSs, since it is also related to the energy consumption of the building. Ergonomic comfort on the other hand, which is difficult to include in the evaluation, since it is mainly dependent on the furnishings, is generally not represented. Acoustic and olfactory comfort, which have a strong effect on the occupants, are also underrepresented, and the segments of their evaluation must be supplemented and strengthened.
The last area, Mind, is rather special due to its complexity. It deals with providing safety and additional services for the occupants; among them there are topics that can partially include the design of the building. Here, an extremely valuable assessment topic is education about the use of the building. Despite its importance, it is only involved in the BCS BREEAM In-use. In our opinion, education of building occupants about the sustainable functioning of the building and providing safety should be addressed in all BCSs. Another important piece of information for building managers, not to be omitted from the topics of the evaluation process in BCS, is the level of occupant satisfaction. In general, many topics addressed in the area Mind are services-related and therefore it is difficult to include them in sustainability BCSs.
For building designers, it is important to know which topic to address in which phase of building design. So, a general recommendation for the further development of BCSs would be that the topics that are directly connected to building design should be specially indicated, since it is important to address them in the early design phases. For example, it is difficult to improve the lighting conditions in the building since it is often not possible to change the position of windows or light fittings or this involves a larger financial investment, so it is better to pay attention to these elements in the design phase. In contrast, many elements in topics from areas Water, Nourishment, Fitness, Comfort and Mind, which are mainly related to the management and services provided in the building, can be improved also after the construction of the building and in buildings that are already in use.
The analysis of this study may serve also as a foundation for further development of a list of management duties and services that should be provided within a building. However, it is important to stress that some services are important for building maintenance only, while many of them provide a healthy and comfortable environment for the occupants as well. However, the boundaries between them are not always easy to discern.

Conclusions
Most of the common sustainability BCSs address the aspects of health and well-being of the occupants in one way or another, but in general they lack a comprehensive and thorough approach. For this reason, specialised BCSs were developed, which are intended not only for dedicated evaluation, but also to offer a better insight into which particular issues have to be followed in buildings to ensure health and well-being of the occupants.
In this review paper, the three most widely used BCSs for buildings in use, LEED O+M, BREEAM In-Use and DGNB Buildings In-Use, were compared with the specialised BCS WELL. These specific BCSs can be used as an extended evaluation instrument in the frame of each particular parent BCS that assesses the sustainability of the building, LEED, BREEAM und DGNB, or as an independent evaluation tool with focus on the health and well-being of users. The review showed that the chosen sustainability BCSs cover the basic requirements for health and well-being of the occupants. The potential for future development of the current sustainability BCSs in terms of occupant health and well-being is also discussed.
The analysis of the reviewed BCSs has shown that basic well-known issues which affect the occupant, such as air quality, comfort and light, are addressed to a certain extent in all of them. In contrast, topics related to nourishment, fitness, water quality and state of mind are less represented or are not represented in an optimal extent regarding their influence on health and well-being of the occupants. The division of the topics into design-dependent and service-management-dependent topics is an important contribution of the study, especially for building developers because they have to know at what point they have to address certain aspects.
It can be established that the specialised BCS WELL is by far the most precise and in some aspects exceeds the scope of sustainable BCSs, for example in providing healthy food, opportunities for physical recreation, etc. It offers a more comprehensive insight yet at the same time it is quite time-consuming and demands that a lot of effort be devoted to very specific topics, which is not always in the interest of the investor.
It is also necessary to mention that some of the studied schemes are already setting specific requirements for a particular use of a building. Good examples for this are the LEED O+M and the DGNB In-Use. To distinguish between different uses is reasonable since the health and well-being requirements of the occupants can strongly depend on the type and use of the building, though it should be noted that many criteria in BCSs are actually targeted at office buildings. Consequently, most of the BCSs are essentially evaluating public, typically office buildings. However, it is quite clear that, in the future, BCSs for other building types will need to be developed.
Another important finding is that a lot of topics connected with health and well-being of the occupants refer to specific legislation. The BCSs often indicate their country of origin since they refer to specific standards, for example ASHRAE standards in WELL and LEED O+M. This means that such BCSs are more appropriate for use in certain countries and cannot be simply substituted for others. Nevertheless, there is still a lack of knowledge around the extent to which health and well-being are covered within the national legislation of countries, so similar studies need to be done in this field of the built environment.
It is particularly important to emphasise the fact that the sustainability of a building is reflected in its full occupancy and that such a level of occupancy can only be achieved by ensuring the health and well-being of the occupants. Funding: The study was funded by the Slovenian Research Agency (Young Researcher Funding 38191). This work was supported by the European Regional Development Fund, Research and development programmes (TRL 3-6), Sustainable and innovative construction of smart buildings (Smart buildings and home, including wood chain: TIGR4smart) (Programme C3330-16-529003). Additionally, the work was also supported by the ARRS -Slovenian Research Agency within the Core Programmes P2-0158 and P2-0273 and the project "Thermo-and Photo-Active Coatings for Windows" (project L2-7630, No. P2-0158, Structural engineering and building physics.