Well v2 certification: indoor air quality, a key metric

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  • Sustainable building and indoor air quality
  • Why indoor air quality must be monitored and managed
  • Indoor air quality among the requirements for sustainable building certifications
  • WELL Certification
  • WELL v2 certification: the “Air” concept
  • Nuvap’s offer

Sustainable building and indoor air quality

Sustainable building, which began in the 1970s in response to the oil crisis and growing public concerns about the environment, has developed over time and with different facets.

A broad definition of sustainable building refers to a new way of building in the built environment, that aims to reduce environmental impact, increase energy efficiency and improve occupant comfort and health. However, in the initial phase and for many years, the concept of sustainable building was mainly and strongly linked to the first two aims and in particular to the issue of emission reduction and energy efficiency.

The strong focus of Real Estate towards reducing or eliminating the building’s energy needs, often not accompanied by the activation of adequate systems for indoor air quality monitoring and ventilation, has generated, over time, a progressive increase in pollution inside the building, as reported by several sources. For example, a study of 100 green buildings has shown that 80% of the buildings were aligned with energy saving strategies, while high indoor air quality was reported only in 30% of the cases. (Source: Licina, Dusan & Bhangar, S & Pyke, C -2019-. Occupant health and well- being in green buildings. ASHRAE Journal 61. 74-77)

The healthiness of indoor environments is a topic of increasing interest, especially in relation to “Sick Building Syndrome”: according to some studies, between 15% and 50% of office and public building occupants have revealed disorders connected to “Sick Building Syndrome”.

In recent years, the increased awareness on these issues, together with the growing importance that international governmental organizations have given to health and well-being, with programs such as the 2030 Agenda for Sustainable Development promoted by the UN, have certainly increased the attention of green building on strategies aimed at protecting the health of occupants.

The green building movement, which has grown over the past few decades, has expanded from a focus on reducing water and energy use to a holistic approach based on people’s health and well-being.

In construction, well-being is the new sustainability

Jonathan Penndorf – sustainability advisor for the American Institute of Architects

The Covid-19 pandemic has made the need to live in healthy and comfortable environments even more urgent, both at home and at work, thus accelerating the development of healthy buildings.

“Health first” is the new expectation for the future, which is driving Real Estate today.

Why indoor air quality must be monitored and managed

The issue of indoor pollution, which has been addressed for decades in the scientific literature and by international organisations such as the WHO, has taken on greater centrality and urgency, following the Covid-19 pandemic. Several studies have highlighted the central role of aerosol in the transmission of respiratory diseases and Covid-19 and the importance of internal ventilation, filtration and the use of monitors that allow real-time observation of indoor air quality.

It has also been widely demonstrated that indoor environments are more polluted than outdoor ones and that exposure to pollutants can generate a wide range of harmful effects on health; from mild and temporary complaints, to the onset or aggravation of chronic or long-term diseases, even serious ones. termine, anche gravi. The main diseases associated with indoor pollution are: allergic diseases, asthma and respiratory disorders in childhood, COPD, respiratory infections (eg. Legionellosis), lung cancer, cardiovascular disease, irritative and comfort disorders (Sick Building Syndrome). It is also important to take into account the impact of indoor air quality on the mental well-being, motivation and performance of workers.

“Make people aware of the importance of indoor air quality and of the related risks must became a priority”

Gaetano settimo – National Health Institute

Indoor air quality among the requirements for sustainable building certifications

Starting from the 90s, in parallel with the development of sustainable construction, associations and governments have developed certification protocols regarding the environmental sustainability of buildings, alongside the more purely energy-related certifications.

These are voluntary certifications, which analyze the entire building process, considering also its impact on the external environment, the health and well-being of occupants, the overall ecosystem.

Among the assessments of these certifications are performance in terms of energy and water saving, reduction of CO2 emissions, improvement of the ecological quality of materials and resources used, design and choice of location. More recent are the certifications specifically aimed at the healthiness of buildings, which focus on people and the concept of healthy building.

Typical examples are LEED and WELL certifications. The first takes into account the performance characteristics of the building; the second assesses the quality of life that the building can offer its occupants.

As people’s health is inextricably linked to the environment where they live, air quality issues are an important global concern for public health. Therefore, the quality of the air we breathe is also a priority aspect in indoor environment and it must be considered in the assessment of the sustainability of buildings.

As confirmation of this, the healthiness of indoor air is among the key requirements of the most important certifications on the sustainability of buildings, with the identification of thresholds not to be exceeded for main pollutants.

In recent years, the demand for building certification has grown considerably, even in Italy. Researches show that building certifications can dramatically increase the value of properties. A survey conducted by REbuild with CBRE and GBCI Europe has shown that certified properties are likely to increase in value by between 7% and 11% more than non-certified buildings.

Well Certification

Principles and Architecture

WELL certification is the gold standard for buildings, interior spaces and communities that seek to implement, validate and measure factors that promote human health and well-being.

Launched in 2014 by the International WELL Building Institute (IWBI), it was the first building certification system focused on people’s comfort, health and well-being..

The intent of the promoters (IWBI) is to advance human health through healthy, safe and comfortable buildings.

The certification, based on a holistic approach, covers a number of concepts, which have different impacts on health. For each concept there are different characteristics to be respected, divided into requirements, which are mandatory for certification, and optimizations, which can be chosen by the project team from among many options.

Today two certification paths are available, WELL v1 e WELL v2, which differ in the number of concepts, requirements and optimisations and in the greater flexibility of the latter, which can be applied to any organisation, project or building type.

WELL v2 involves the assessment of:

  • 10 concepts: Air, Water, Nourishment, Light, Movement, Community, Mind, Materials, Sound, Thermal Comfort
  • 1 additional concept: Innovation (not foreseen in WELL v1)

The concepts are broken down into:

  • 24 Requirements (reduced towards WELL v1)
  • 97 Optimizations (more than in WELL v1)

The certification process considers an assessment according to a scoring system. All requirements must be achieved, together with a certain number of optimizations for each concept, which will allow to obtain points.

Additional points can also be obtained within the Innovation concept.

Depending on the total points achieved, it will be possible to reach four levels of certification:

  • Well Bronze
  • Well Silver
  • Well Gold
  • Well Platinum

The WELL v2 scoring system allows to reach a maximum of 110 points, by working on the features within the 10 concepts and the Innovation concept.

Types of project

WELL v1 includes 3 types of project:

  • Building (it mainly concerns the design, construction and operations of office buildings with at least 90% of the floor space occupied and managed by the owner of the building).
  • Interior(office projects that occupy only part of a buildings space , or those that occupy an entire existing building that has not undergone major renovations).
  • Core and Shell (projects that intend to implement core features of the entire building, for the benefit of future tenants, and in which at least 75% of the area is occupied by one or more tenants and/or serves as a common space in the building accessible to all tenants).

On the other hand, WELL v2 provides for 2 types of projects:

  • Owner occupied building (the project is primarily occupied by the project owner, which may be different from the building owner).
  • Well Core (the project owner occupies a small part of the project area and rents most of the space to one or more tenants).

The certification process

The certification process is based on 4 key steps:

  • Assessment
  • Implementation
  • Verification
  • Monitoring

Going into more detail about the process, there are some specifics that you need to know:


The registration phase allows you to communicate to the certification body the intention to start the certification process, providing basic information about the project and its purpose and to define the type of certification to be pursued (WELL v1, WELL v2). The main information concerns the size of the building (in sm).

Documents Requirements

The WELL protocol requires the submission of the defined documentation that demonstrates the compliance with the protocol’s requirements. All documents, like the entire certification process, is managed through an online platform, available from the moment of registration. There are three main types of documents:

  • Annotated Document: existing documentation regarding projects, which can be used to meet WELL requirements (Design, Construction, Operations Planning, Policies, Materials,…).
  • Letter of Assurance: documentation produced by professionals that confirm the successful execution and compliance with a specific requirement (Owners, Architects, Contractors, MEP Engineers).
  • General Document: generic documentation to support the project (signed WELL certification agreement, Project checklist, Building maps, Mechanical drawings, Description of the project and the features to be implemented, Proof of work completion).


WELL pre-certification, which is achieved through different pathways for WELL v1 and WELL v2, allows owners to demonstrate to prospective tenants the commitment to health and well-being and the characteristics that the project can achieve during full WELL certification.

For WELL v1 projects, pre-certification is an optional review pathway, which focuses on the design, construction and operational strategies foreseen for the project.

In the case of WELL v2, pre-certification may be required at an intermediate stage of the project, prior to the actual documentation review and final performance verification. However, in order to obtain this interim designation, which can help projects communicate progress towards achieving WELL certification, documentation demonstrating compliance with all preconditions and achieving at least the minimum score is required.

Documentation Review

All documentation must go through the review process through the WELL Reviewer. Once all the documentation has been judged satisfactory, the performance achievement is verified.

Performance Review

WELL is a performance-based system, therefore each project is verified through on-site tests of various parameters. Tests can be performed if certain eligibility criteria are met (Documentation Approval, Employment Certification, Occupation of space for at least 50% of the capacity of occupation,..).

Performance testing is carried out by an authorized testing agent, the Performance Testing Agent, which is a GBCI-trained person who, according to the directives and recommendations provided, performs the measurements on the spot. The testing agent works for a “WELL performance testing” organization which may be GBCI or a GBCI approved organization (it is important that there is no conflict of interest with the project).

WELL Report

The WELL report provides an assessment of each individual feature and requirement in the certification process. If the project has not achieved the set objectives, the report will indicate the non-conformity and it will be possible to implement corrective actions.

Certification and Monitoring

Once all WELL requirements have been verified, certification is obtained. To maintain the status of a WELL certified building, it is necessary to implement the monitoring and reporting activities on an annual basis, up to the re-certification.

Monitoring and reporting activities are divided into three main areas:

  • Survey on building occupancy.
  • Evidence of maintenance activities (filter replacement intervention reports, maintenance planning, etc.).
  • Continuous monitoring of environmental parameters (e.g. air and water).

Certification has a duration of 3 years; subsequently it is necessary to activate the re-certification process. Re-certification requires that all monitoring activities and incremental progress have been performed, otherwise the certification can be revoked.

WELL is in use by over 4,000 projects in more than 60 countries, encompassing over half a billion square feet of real estate around the world.

International Well Building Institute

WELL v2 Certification: the “Air” concept

The Air concept was developed with the aim of ensuring high levels of indoor air quality during the life of a building, through different strategies including the elimination or reduction of polluting sources, the appropriate design of active and passive buildings, operational strategies and interventions in human behavior.

Monitoring of indoor air quality, compliance with good air quality levels and communications are key elements of the Air concept.

The necessary requirement to obtain WELL v2 certification or re-certification is compliance with the maximum concentration levels for the following pollutants:

  • Particulate matter PM2.5: 15 µg/m3
  • Particulate matter PM10: 50 µg/m3
  • Benzene: 10 µg/m³ , Formaldehyde: 50 µg/m³, Toluene: 300 µg/m³ (lab test) or Total VOC: 500 µg/m³ (continuous monitoring with sensors)
  • Carbon monoxide: 10 mg/m³ [9 ppm] [9 ppm]
  • Ozone: 100 µg/m³ [51 ppb] [51 ppb]
  • Radon: 0.15 Bq/L [4 pCi/L] (measured by a professional) [4 pCi/L]

To reach a higher level of indoor air quality and obtain additional scores through optimizations, it will be necessary to reach more challenging levels for some pollutants and to expand the range of pollutants controlled:

  • Particulate matter PM2.5: 10 µg/m3, Particulate matter PM10: 20 µg/m3 (2 points)
  • Carbon monoxide: 7 mg/m³, Nitrogen dioxide: 40 µg/m³ (1 point)
  • Acetaldehyde: 140 µg/m³, Acrylonitrile: 5 µg/m³, Benzene: 3 µg/m³, Naphthalene: 9 µg/m³, Caprolactam: 2.2 µg/m³, Formaldehyde: 9 µg/m³, Toluene: 300 µg/m³ (1 point)

Since WELL certification places a high value on continuous monitoring of indoor air quality and awareness of the importance of indoor air quality, it will also be possible to obtain additional scores by taking action in these two areas of WELL v2:

  • Continuous monitoring (1 point)
  • Awareness Initiatives (1 point)
Continuous monitoring (1 point)

The WELL Air concept, in the section related to this feature, therefore requires continuous monitoring of certain pollutants, to make occupants aware and responsible for environmental quality.

The installation of sensors for continuous monitoring in each building is recommended, also because the types and concentrations of pollutants fluctuate continuously causing negative effects on health, without being perceived. In this way it is possible to promptly correct any deviation in indoor air quality values and minimize the exposure of the occupants to pollutants.

It is considered important to select robust and calibrated sensors, positioning them correctly in the environment.

Monitoring must be carried out in compliance with the following requirements:

  1. continuous monitoring with devices capable of detectingat least three of the following parameters:
  • PM2.5 or PM10 (25% accuracy at 50 μg / m3).
  • Carbon dioxide (10% accuracy at 750 ppm).
  • Carbon monoxide (accuracy 1 ppm at values between 0 and 10 ppm).
  • Ozone (accuracy 10 ppb at values between 0 and 100 ppb).
  • Nitrogen dioxide (accuracy 20 ppb at values between 0 and 100 ppb).
  • Total VOC (accuracy 25% at 500 μg / m3).
  • Formaldehyde (accuracy precision 20 ppb at values between 0 and 100 ppb).

2. At least one device shall be installed per 325 m2, according to the following requirements:

  • 1.1-1.7 m above the floor, in places where occupants usually stand.
  • At least 1 m away from doors, windows and air / exhaust vents.
  • Measurements are taken at intervals of no more than 10 minutes for carbon dioxide and no more than one hour for other pollutants.
  • Data must be submitted every year via the WELL Online portal.
  • The devices are recalibrated or replaced annually, with documentation certifying their calibration or replacement sent every year through WELL Online.

Nuvap devices allow the continuous monitoring of all parameters required by WELL v2 certification during the life of the building, except for the following parameters which are part of one of the possible optimizations: Acetaldehyde, Acrylonitrile, Benzene, Naphthalene, Caprolactam, Toluene..

Awareness Initiatives (1 point)

Raising the awareness of occupants about the risks associated with high exposure to air pollutants and the actions that can be taken to reduce these risks, can encourage them to seek areas for further improve air quality. WELL certification therefore gives the opportunity to gain additional points by taking action in this area.

Information on air quality, measured according to the continuous monitoring criteria outlined above, must be made available to the occupants as follows:

  • At least one display is positioned in an prominent position, at a height of 1.1–1.7m, every 325 m2 of regularly occupied space.


  • The requested data are displayed on a website or telephone application accessible to occupants. Visible signs, indicating where the data can be accessed, are placed every 325 m2 of regularly occupied space.

In addition, the data submitted must include one of the following alternatives:

  • Concentrations of measured parameters.
  • Qualitative air quality results (e.g. with colored graphic images).

Nuvap ProSystem technology platform fully complies with WELL v2 certification requirements.

The monitored data is displayed both through an App and through a Web interface. In both interfaces, the information is updated approximately 4 times per hour and presented in a simple way, with clear reference to the relevant thresholds.

Both in the App and via the Web, there is a library that indicates for each pollutant the possible sources, the effects, the reference values and some behavioral solutions that can be implemented to reduce the presence of pollutants.

The same information, in a more detailed version, can be enclosed in a periodic report that Nuvap can process on request. Nuvap is available for training on indoor pollution issues. To further customize the experience of the occupants, it is possible to integrate the collected information into third party portals, applications or dashboards, thanks to the complete set of APIs that Nuvap makes available..

Nuvap’s offer

Nuvap is an Italian Green-Tech start up, set up to help organizations that want to promote people’s health and well-being, through solutions for monitoring and managing indoor air quality.

The involvement of engineers, physicists, computer scientists and leading universities led to the development of an international patent and innovative solutions that provide a dynamic analysis of air health, insights for improvement, and communication and reporting tools to facilitate the implementation of companies’ sustainability strategies.

The company’s developments are focused on technologies for the detection and analysis of environmental data. Nuvap’s technological partners are Italian and production is located in Italy.

Nuvap’s technology is protected by an international patent, relating to the exclusive system of combined and constant monitoring of polluting agents, which may be present in the environments in which we live.

The company has participated to two open innovation projects, “Insurtech for Welfare and Health”, and “Healthy people and work environment”. It has also taken part to several international research and experimentation projects: LIFE MEGA, RAFAEL, GO, SMAG, NUMEQS.

Nuvap won Edison’s Pulse 2017 Award, “ Best Smart Home Technology”. In 2019 it won the eHealth4all Award, as the best technology for prevention.

“We want to support projects, places and lifestyles that are sustainable for people and the environment”.



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