Air quality in green building certification: what you need to know

Indoor air quality (IAQ) is a keystone of building sustainability, and an area where guidance is extensive and specific. Good IAQ isn’t just about compliance – it directly impacts occupant wellbeing, productivity and even cognitive performance, making it a critical factor in creating spaces where people can thrive.

Green building certifications have evolved beyond being a differentiator to become a market standard, expanding in scope to reflect the holistic nature of sustainability and the full building lifecycle. 

Green certification schemes

Guidance around IAQ is extensive and specific, and it sits at the heart of leading certification systems, such as BREEAM, LEED, WELL and Fitwel, which share common focuses on ventilation, filtration, testing and pollutant source control.

The certifications are not like for like, and projects aiming for a specific one should work directly from the guidelines for that standard in specifying decisions to ensure they meet that awarding body’s definition of best practice.

While air-quality testing thresholds for the main pollutants lie within a central range defined largely by World Health Organisation (WHO) guidelines, there are important differences in approaches and processes required by the main certifications.

Air-quality testing thresholds

Air-quality testing thresholds are the most significant part of the relevant sections of these certifications – and the part that should drive specification choices, particularly for products to which occupants will be exposed.

There is a degree of consistency in the maximum values for some key pollutants – such as a limit of ≤500 μg/m³ for total volatile organic compounds (TVOC), compounds that can contribute to headaches, respiratory irritation and long-term health risks if levels are too high. Meeting the limits is essential for compliance with building standards and wellness certifications. However, because measurement methods vary, what worked previously may not meet requirements next time.

Coatings play a critical role in meeting these requirements. Low-emission paints, varnishes and sealants are often mandatory under certifications like BREEAM and WELL because they can significantly reduce VOC emissions, a major contributor to poor IAQ. Choosing compliant coatings is therefore a key specification decision for architects and designers aiming to protect occupant health and achieve certification.

Different approaches in different standards

Some certifications require the use of products with specific air-quality specifications, while others require pollutant values to fall below key values in post-construction testing. For example, BREEAM, the most well-established certification, restricts VOC and formaldehyde emissions from paints, varnishes, adhesives, sealants and flooring. Decorative paints and varnishes must meet low-emission criteria, with at least five of seven specified product categories meeting VOC requirements.

When identifying these products, environmental product declarations (EPDs) are a specifier’s best friend, covering embodied carbon but also key metrics for indoor air quality.

Indoor pollutant standards across major building standards

Work with manufacturers

The key to cracking the code with individual products is collaboration between specifiers and manufacturers. Alongside detailed and malleable project knowledge, manufacturers have an acute understanding of what is required for specific parts of major building certifications. As the certifications themselves become more common in the built environment, so should this level of collaboration. It is an opportunity for specifiers who have long been jacks of all trades to connect with multiple masters of one at every stage of the build process.

Planning and processes

Evidence of best practice in IAQ isn’t just required in the form of the finished product, awarding bodies also place serious emphasis on implementation of the right processes during construction. Projects need to demonstrate they are thinking about IAQ from the earliest stages of construction and that they are actively managing it rather than just passing the test at the other end. This includes early decisions on materials such as coatings, which can have a lasting impact on VOC levels. Specifying low-emission paints and varnishes during design stages helps avoid compliance issues later – and supports healthier environments from day one.

The WELL building standard requires projects to detail plans for construction pollution management, humidity control and air-flush strategies to minimise post-construction contaminants. BREEAM goes a step further, requiring projects to draw up an indoor air quality plan as a mandatory pre-requisite completed during the early design stage (RIBA Stage 2). This must establish site-specific measures to minimise pollutant concentrations during both construction and operational phases.

Again, it is time to bang the drum on collaboration – there is no substitute for specific expertise on design plans for air quality and ventilation and filtration strategies. The details matter, and it often needs an expert eye to cover all the little things. The LEED v5 framework requires the use of entryway systems with grates, grills or slotted systems plus rollout mats to capture dirt and particulate matter before they enter the building. On a large-scale project, this is a comparatively small addition, but it illustrates the detail that these certifications have grown to encompass.

Completion and beyond

More commercial real estate than ever is receiving top grades for sustainability, and this is pushing leading certification schemes to evolve to retain their status as a marker for highest-quality assets. They are doing so in tandem with businesses that are climbing the learning curve when it comes to properly evaluating their operational footprints. This means greater scrutiny of operational performance once the project is in use in terms of energy – but also IAQ.

There is no lack of appetite for certifications that attest to continued performance in health and wellbeing – building owners and landlords want proof that their asset will keep delivering for tenants and occupants. As a result, standards such as Fitwel, which is specifically focused on occupant health, safety, and wellbeing, are becoming more attractive across the board.

Fitwel is leading the extension of IAQ requirements to how buildings are managed on a day-to-day basis. Provisions include mandating a building-wide smoke-free policy within 60 feet or 20 metres of entrances, alongside recommendations for filter replacement schedules for ventilation systems and pre-occupancy flush-outs for one hour ahead of operational hours. Evolving to encompass projects’ entire lifecycle is how certification will continue to deliver their green premium, and it makes IAQ all the more important.

Vehicles for progress

Sustainability and wider ESG work are less a journey than a continued evolution – there is no end point where the built environment can pat itself on the back for a job well done. This is something that green building certifications have acknowledged, and their growth to include health and wellbeing, as well as considering more of the building lifecycle, are a case in point.

Golden rules

When considering IAQ for these certifications, there are four golden rules for specifiers:

• Work directly from the certification you are aiming for
• Use EPDs and product data sheets to be sure of pollutant values
• Draw on the expertise of manufacturers

• Think beyond completion.

The fact that certifications are examining IAQ more often and with more scrutiny underscores its importance in healthy and sustainable buildings. This doesn’t have to slow projects down, rather it holds the potential to drive closer collaboration between specifiers and manufacturers, which is good for everyone.