To Reduce Disease and Fight Climate Change, Design Buildings that Breathe

Healthy air quality in buildings improves cognitive function and combats the spread of disease, but its implications for carbon reduction are perhaps the most important benefit.

May 10, 2022

Principal / Director of Design Performance, NBBJ

The benefits of fresh air have long been tied to health and productivity. But as we continue to examine the built environment’s role in climate change, its implications for reducing a building’s carbon footprint are increasingly important. In this post, the fourth in a series about healthy buildings (the first three posts covered light, noise and access to nature), we illustrate how solutions like operable windows and breathable facade systems are key to maintaining a healthy indoor environment and reducing energy use in buildings. This post was co-authored by Peter Alspach and Eric Phillips.


Long before the pandemic, studies indicated the correlation between indoor air quality and health. Lower levels of outdoor air supply have been associated with increased sick leave among employees, while improved ventilation corresponds with higher test scores and decreased school absences among students. Covid-19 further underscores the importance of proper ventilation and air quality in preventing disease transmission since it has been shown that the virus spreads more rapidly in poorly ventilated spaces. And while natural ventilation has positive implications for health and cognition, it can also reduce a building’s carbon footprint in lieu of conventional mechanical ventilation and air-conditioning systems.

While few climates can rely completely on natural ventilation, many climates have significant periods of the year where natural ventilation is an effective and low-energy solution to providing increased ventilation rates and space conditioning. Designing for mixed-mode buildings—buildings that can operate mechanically or naturally—allows for the best of both worlds in a changing climate.

Healthy air drives performance—of people and buildings 

The air we breathe is affected by hundreds of indoor and outdoor pollutants, and the baseline for what is considered healthy air—as defined by minimum air quality standards—is below what is ideal for performance. Good indoor air quality positively affects creativity and cognition, while even minor indoor pollutants can inhibit our ability to concentrate and process information. That’s because cognitive performance increases significantly when indoor CO2 levels are lower than those that result from current ventilation standards.

Natural ventilation can provide increased levels of outside air to a space relative to code. Bringing in two to four times as much outdoor air as required by code not only increases performance and reduces the risk of viral transmission, it also decreases energy use and operational carbon emissions. For example, in a Tokyo University of Science study on the energy saving efficiency of a natural ventilation strategy in a multi-story school, researchers analyzed ventilation and cooling load reductions based on the opening and closing of several windows. The results showed that the natural ventilation strategy could effectively establish required indoor conditions and compared with the mechanical ventilation system, could decrease energy consumption by approximately 30%.

To improve ventilation by increasing air exchange rates, features like operable windows or garage doors—which open to the outside and can be used for natural ventilation or to create dynamic indoor-outdoor spaces—can be incorporated into a building’s design. Classrooms at the new lower school campus of the Westmark School in Encino, CA—which is targeting LEED Gold certification as well as International Living Future Institute Zero Carbon certification—feature oversized doors that can be opened to create regular moments of engagement with the powerful benefits of outdoor learning and reduce the need for traditional mechanical systems.

The new lower school campus at the Westmark School outside of Los Angeles incorporates hangar doors that harness energy savings as well as the benefits of nature to improve cognitive performance for its students. 


Natural ventilation increases resiliency

Natural ventilation’s benefits extend beyond reducing disease transmission and carbon emissions. It also allows our buildings to remain habitable, even under power outages and extreme weather conditions. Hospitals are now beginning to re-examine operable windows for patient rooms, even if only to be used in an emergency. And during Covid, some hospitals were able to use operable windows to allow for retrofits of increased isolation and higher ventilation rates.

The Dumfries and Galloway Royal Infirmary in Scotland features high-performance operable windows that help maintain a comfortable, energy-efficient internal climate and enable optimum natural light in patient rooms.


A breathable facade design takes the idea of resiliency even further. This envelope-first approach prioritizes energy efficiency and comfort simultaneously and enables thermal autonomy—a building’s ability to maintain its thermal environment if power is compromised. Thermal autonomy is critical during events like heat waves, when sealed environments such as high-rise multi-family residences can become dangerous, especially for elderly or otherwise compromised populations.

Thermal autonomy is also important when quantifying energy consumption, since it measures how much of the available ambient energy resources a building can harness. Currently, researchers at UC Berkeley are working to create an integrated building design process that combines the assessment of three internal air quality factors—thermal, luminous and ventilation autonomy—into a single workflow to help predict building performance.

These types of porous building solutions are not limited only to new buildings. Many pre-war buildings already feature operable windows, an added benefit when renovating or retrofitting. Building additions or portions of new constructions can also be designed to incorporate natural ventilation strategies. For example, the atrium at the Bill & Melinda Gates Foundation in Seattle, WA—which serves as the central gathering place for the campus and can accommodate up to 1,000 people—features operable windows while the connected buildings are sealed, allowing the adjacent buildings to reap the benefits of natural ventilation in a targeted biophilic space.

The operable windows in the atrium at the Bill & Melinda Gates Foundation provide thermal comfort and energy-saving benefits while enhancing connection to the outdoors.


Finally, to effectively harness the benefits of natural ventilation, it is important to focus not just on building functionality, but also building form. Designing to allow as many spaces as possible to exist in proximity to operable windows, for example, has synergies not only with ventilation but also daylight access—another highly critical aspect of human health and wellness in the indoor environment.

Avoiding pollution and increased energy use

It is important to note that while the benefits of natural ventilation are many, there is also the potential for noise and air pollution, and increased energy use that can counteract conservation efforts, if not implemented correctly.

Periods of high outdoor air pollution—wildfire smoke and pollen are the two most common issues, as well as noise pollution from construction or traffic—are a concern when relying primarily on natural ventilation. Before implementing operable windows, a local air quality risk review is critical, and some locations may wish to continuously monitor local air quality and signal building users when ambient air quality is poor. The ability to run “mixed mode” (switching back and forth between operable windows and mechanical ventilation) and having a well-designed mechanical ventilation system in place during periods of pollution is also important. For example, persistent wildfires in the areas surrounding the Westmark School often negatively impact air quality, so individual classroom spaces feature oversized doors that can open and close. When the doors are closed, students still receive the benefits of daylight and nature without breathing contaminated air. 

Increased energy use when operable windows are open can be detrimental to energy conservation—like driving a car with the heat on and the windows down—however, there are ways to incorporate operable windows while also mitigating the energy penalty. Automation or mechanization of windows or select windows within a space that serve as a signal for other manually controlled windows can help alleviate this problem. Window switches that signal open windows to maintenance staff and that can also prevent heating and cooling when the windows are open are another solution. Signaling systems like a red or green light are useful if tuned correctly and lastly, use of windows in spaces that have greater ownership—such as residences or private offices—have a lower likelihood of misuse.

NBBJ’s Seattle office features operable windows which utilize a signaling system that indicates when windows can—and should—be opened or closed.


Finally, changes in climate can also result in impacts to local air quality, increasing ground-level ozone and particulate air pollution. CO2 concentrations in outdoor air are rising and projected to increase due to continued emissions, exacerbating current challenges with high indoor CO2 levels, especially with mechanical systems where the ability to increase ventilation rates is limited. Operable windows provide a large jump in outside ventilation, which can help to maintain indoor CO2 levels, even as outdoor levels rise.

In conclusion

Because of the potential benefits, natural ventilation is increasingly being proposed as a means of saving energy and improving indoor air quality. Design solutions like operable windows and breathable facades that can be applied on a variety of building types and scales improve air quality and reduce carbon emissions in buildings while providing added benefits for the health, performance and safety of the people who occupy them.

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Want to Reduce Your Company’s Carbon Footprint? Start with Your Headquarters

April 28, 2022

Partner, NBBJ

This post, which is part of a series on how to reduce carbon in the built environment, was co-authored by Tim Johnson and Peter Alspach. The first post in the series served as an introduction, and the second focused on embodied carbon reduction.


The nature of work is changing in a myriad of ways, with more talent relocating to areas outside of cities and the seemingly permanent shift to hybrid schedules. As a result, corporations are rethinking their headquarters, designing them for a different set of uses and an evolving workforce. These same companies are also increasingly concerned with social responsibility, including their offices’ carbon footprint.

Recently, our firm was tasked with designing a net-zero building for a corporate client on the East Coast. While the adaptive reuse of part of the current headquarters served as a jumping-off point, the organization’s suburban location required an addition to the existing building as well as increased focus and diligence in managing elements such as embodied and transportation carbon—two main areas of concern in a net-zero energy facility. The client also specified that carbon neutrality be achieved through the construction and operation of the building itself rather than supplemental means such as the purchase of carbon offsets.

How can an organization reconcile the need to expand their presence with their obligation to decrease carbon emissions? Below, we explore strategies and solutions for companies to do so through the planning, design and construction of their buildings.

Innovate through Materials and Building Techniques

For our East Coast corporate client, the use of sustainable materials and building practices factored in greatly when planning and designing the addition to the existing headquarters. One environmentally friendly, cost effective and beautiful alternative to traditional building materials like concrete and steel is mass timber. Substituting wood instead of conventional building materials can reduce emissions by 69%, and using mass timber in half of expected new urban construction could provide as much as 9% of global emissions reduction needed to meet 2030 targets.

In addition to curbing greenhouse gas emissions, mass timber’s benefits extend to the building and construction process. It is well suited to offsite manufacturing and prefabrication—another highly sustainable building method that can reduce construction waste by 40% and carbon emissions by 35%—since much of the labor (cutting and assembly) is done in factories. It is estimated that because they are prefabricated, use of mass timber panels can bring significant cost savings for construction projects and reduce construction time by up to 25%.

Employ Alternative Energy Sources

While embodied carbon is of greater concern in the long run, operational carbon—a building’s everyday energy use—accounts for 28% of the built environment’s carbon footprint. Alternative energy sources like wind, solar and geothermal can significantly reduce a building’s reliance on fossil fuels. For example, the Thermal Energy Center at Microsoft’s headquarters in Redmond, WA, employs a geothermal system comprised of hundreds of wells drilled 550 feet underground that serves as the heating and cooling source for the campus, eliminating fossil fuel usage.

Cities are also beginning to require the use of alternative energy sources in both new construction and adaptive reuse projects to meet their carbon reduction goals. For example, Boston’s BERDO 2.0 ordinance mandates that buildings of a certain size must report their carbon emissions to the city on an annual basis and pay a fee on any overages, and in the past 18 months Washington, DC, New York City, Denver, Seattle and St. Louis (among others) have all enacted building performance standards.


Microsoft’s Thermal Energy Center in Redmond, WA, taps clean energy deep underground for the organization’s new campus.


Curb Transportation Carbon with Amenities that Attract Talent and Benefit the Community

Transportation carbon is a concern when dealing with a suburban workforce that mostly commutes using cars. According to a Pew Research study from 2016, 21% of urban dwellers use public transit on a regular basis compared to only 6% of suburban residents. The movement toward hybrid work means fewer people commuting each day has positive implications for transportation carbon, especially when coupled with amenities that benefit the community and attract talent.

In addition, due to public and private investment making suburbs more dense, walkable, bike-friendly and less dependent on cars, as well as the competition to attract bright young talent who want to live and work in lively places, many companies are imbuing their suburban campuses with shops, restaurants, hotels, residences, affordable housing, community services and public parks. When going to work also includes a stop at the gym, a quick trip to the grocery store and a dinner out, the transportation carbon associated with making separate trips is reduced significantly—not to mention providing an experience that draws talent to the office.

Lastly, there is an increased trend in electric vehicle infrastructure required of commercial office projects. The electrification of the transportation sector is a key part of global carbon emissions reduction plans, and the build-out of the supporting infrastructure is vital to its success.


At Amazon’s HQ in Arlington, VA, the “helix”—a walkable ramp wrapping the building with trees and greenery planted to resemble a mountain hike—is open to the public on weekends, providing a green amenity for employees and the community alike.


Reuse, Renew, Reposition

According to JLL research, two-thirds of the national office inventory is more than 30 years old and likely to become obsolete, while 91% of net occupancy growth for the past decade is new and repositioned supply. An increased emphasis on energy reduction in buildings coupled with the fact that many aging commercial properties are transforming from assets to liabilities means that adaptive reuse, renewal and repositioning are viable strategies to help reduce the embodied carbon impact of the built environment, enhance a building’s value and decrease energy use and costs.

Implementing upgrades that increase sustainability and energy efficiency—such as replacing aging infrastructure, proactively adapting to regulatory changes and designing for resiliency—as part of a larger repositioning of the property creates a compelling product in the marketplace that appeals to both developers and tenants.

In Conclusion

Balancing the energy savings of sustainable building practices and renewable energy sources with a building’s embodied, operational and transportation carbon footprint is a complicated equation. However, large corporations have an obligation to address carbon emissions due to their outsized role in driving global climate change. By making informed decisions about materials, building techniques, energy and transportation, organizations can significantly decrease the carbon footprint of their buildings while also setting an example for how to create sustainable, responsible buildings and campuses.

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Influencing Action: The Power of Perspective

Clear Eyes for Climate Change Action

March 22, 2022

Managing Partner, NBBJ

On January 13, 2022, I stood on a remote saddle high in the Ellsworth Mountains; it was about –20°F, but I was geared up for the cold. The view was infinite and amazing to behold. Spectacular mountains as high as 16,000 feet and glaciers that average 6,000 feet deep below the surface spanned the horizon. I felt I stood at the very edge of the Earth—an extreme place to be, yet a place so remote that I could not deny the perspective on life and our planet it offered.

The vast Antarctica continent extending beyond the Sentinel Range of the Ellsworth Mountains.


To be here, a place solely of rock, ice, wind, silence and extreme cold was to know self-reliance, awe and how fragile life can be. Still, something inexplicable was happening—it had snowed several inches the night before and I would soon discover more snow was coming in a raging storm a few days off.

Antarctica is a desert—the driest continent, with an average precipitation of 1.5 inches per year. Yet more than a foot of snow fell over the two weeks I was in the Ellsworth Mountains. “Yes, our climate is changing,” I thought, “this snowstorm should not be happening.” A few days later at high camp, as a new storm raged on, I wondered if the intense 60 mph winds I was experiencing would accelerate and endanger my life, and whether climate change was the culprit. That day, in that moment, I feared climate change.

My adventure became a personal field study, clarifying what I’ve sensed, read and heard about climate change.

Storm clouds brewing over Mount Vinson’s high camp and Mount Shinn beyond.


Returning to Seattle, 9,000 miles from Mount Vinson and the Ellsworth Mountains, I reflected on the essence of leadership and organizational responsibilities. Leaders ensure their organization is guided by a compelling vision, relevant goals, coherent actions and on-course trajectories. Organizations that create the built environment must be concerned with the health of society.

The long journey home descending the Branscomb Glacier.


Advancing the health of society safeguards our ethical purpose. Ethical purpose is an authoritative force for relevancy. Being relevant guarantees success. Finally, addressing climate change guarantees relevancy.

NBBJ is a leadership intensive practice—a grand experiment where our role-based organization vests authority and responsibility with the role each of us fulfill. We express this cultural and values touchstone by highlighting that “we lead from every chair.”  This means that it is up to every NBBJer to ask, “How will I reduce carbon today?” If ever there was a wicked problem that requires leaning in, learning, looking around the corners and being proactive, it is the challenge to become a net-zero carbon society.

Perspective is powerful.

We must act now to create sustainable, resilient, zero-carbon experiences, buildings, and communities.


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