The air we breathe is a major factor in our long-term and short-term health. Since the average American spends 85 percent of their life inside buildings, it is surprising, if not negligent, that indoor air contamination is neither adequately addressed by governments nor given sufficient attention by the public. This is a stark contrast compared to food and water contamination. 

When a foodborne illness breaks out, nationwide recalls follow. If water resources become contaminated, municipalities issue boil water advisories or direct their constituents to drink from bottled water. Suppliers and polluters are held legally accountable when such instances arise. Meanwhile, similarly deleterious health effects from poor indoor air quality (IAQ) are accepted as facts of life. 

State of Play Today

Many buildings have poor air quality simply because they were built before the advent of ventilation systems. However, even considering buildings with modern mechanical systems, today’s minimum ventilation standards are primarily designed to control odors, not to support human health. 

Furthermore, many buildings do not meet these minimum standards in operation. As soon as a building receives its certificate of occupancy, entropy marches forward, and its mechanical and control systems age and develop faults. Filters get dirty, dampers get stuck shut and mold grows. 

Every day, millions of students are sent into classrooms with no ventilation. Millions of workers step into offices with stale air. Millions of senior citizens live in facilities with inadequate infection controls. In many of these buildings, HVAC systems go uninspected, worsening the delivery of clean air and possibly delivering pathogens or mold to occupants. 

We now know that colds, flu, strep and COVID-19 are spread predominantly through indoor air, particularly when ventilation and filtration are poor.

COVID-19 is no longer an emergency today as it was in 2020. However, to date, long COVID has inflicted disabilities of various kinds on an estimated 400 million people worldwide, costing the global economy about $1 trillion per year, or 1 percent of its total output, notes a research report in Nature Medicine (https://go.nature.com/3YgVbqv). 

Even when respiratory infections are not severe, they affect our social lives, keep us out of school and work, and can cause serious harm to the most vulnerable among us. Their impact on the economy, student learning outcomes and public health is measurable and significant. 

Under-ventilated spaces are not only correlated with disease transmission, but they also have elevated carbon dioxide levels that reduce alertness, focus and task performance. In schools, this worsens learning outcomes and test scores. In offices, this impairs employee productivity and affects businesses’ bottom lines. 

Through health-care bills, premature death, worsened productivity and social disruptions, pre-COVID estimations of the public burden of poor IAQ total about 1 percent of industrialized countries’ GDP, reports Environment International (https://bit.ly/3zX9hnB). In the United States, this is about $100 billion annually, notes Environmental Health Perspectives (https://bit.ly/4gYt070). Accounting for long COVID and learning losses at school would show that the real costs are much higher.

Healthy Buildings Paradigm

It has been a commonly held sentiment that, in terms of liability, HVAC engineering is a safer profession than other engineering disciplines. “When an HVAC engineer makes a mistake, people are just uncomfortable, but when a structural engineer makes a mistake, buildings and bridges fall down,” the saying goes. However, this perspective is wrong — HVAC systems affect more than our comfort. 

2020 should have been a watershed moment, sparking a post-pandemic IAQ revolution and improving our health, productivity and economy. Instead, some of us seem resigned to believing the false choice that we can either accept a constant onslaught of colds, flu and endemic COVID-19 or return to 2020-style lockdowns to avoid them. Others seem to think that expensive and energy-inefficient buildings are the only alternative to the status quo.

It is time to break out of this binary mindset.

We simply should not be sending our kids to learn in classrooms that make them sick and groggy. Business should not be conducted in spaces where we are not productive. We must design our HVAC systems to strengthen our health and economic prosperity, and we must ensure these systems work as intended throughout their entire operational life. 

To realize the promises of this future, a paradigm shift is needed among stakeholders of all levels, from governments to project owners to designers to technicians to occupants. We need new ways of approaching HVAC design and maintenance, conceiving a building’s role as a public health tool, and accounting for the costs and benefits of improving air quality. 

The first step to realizing this new paradigm is to understand that the status quo is, in fact, the expensive path; investing in healthy buildings would deliver cost savings to all stakeholders.

Under a new paradigm, human costs must be woven into workplace HVAC design and management cost analyses. Model frameworks for doing so already exist (https://bit.ly/4f2JglP). Health insurance premiums and disability payouts far exceed IAQ improvement and filtration costs. Business owners investing in healthy office spaces are expected to see returns exceeding a 10:1 benefit-cost ratio (https://bit.ly/3NmeQPn).

While the owners of public buildings may not see a direct payback in their bottom line for healthy building investments in the same way that workplaces might, the public itself would reap the benefits, reducing the $100 billion annual burden on Americans. So, these projects should be publicly funded and backed by the government.

There are signs that the ground is already starting to slowly shift. 

In 2023, ASHRAE released Standard 241: Control of Infectious Aerosols, the first-ever health-based enforceable IAQ standard (https://bit.ly/3BQuyQf). The same year, the Johns Hopkins Center for Health Security released a Model Clean Indoor Air Act for state and municipal governments to adopt (https://bit.ly/3BCxf8f). And in 2024, the bipartisan bill H.R. 9131: Indoor Air Quality and Healthy Schools Act was introduced to the U.S. Congress (https://bit.ly/4eYPhzJ). 

The market is also beginning to march toward a healthy building future. In many new Class A office buildings, owners such as Amazon and JP Morgan outfit their spaces with air quality dashboards and advanced building automation systems to optimize air quality. Boston public schools voluntarily display real-time IAQ data for every classroom online. 

HVAC Industry’s Role

It is incumbent upon industry insiders to help their clients understand healthy buildings’ imperatives and propose cost-effective solutions. 

Governments and standard-setting agencies must be engaged to address and mandate clear ventilation design criteria for human health. 

Economists, planners and owners must consider human costs in their analyses, both the direct costs burdened by the client and the externalities. 

Today’s standard equipment and technology already provide all the solutions needed. Engineers must be thoughtful and creative in design, not relying on unproven, expensive, energy-intensive or oversized designs. Emerging technologies, such as ionizers and other chemical air disinfectants, make big promises but have not yet shown to be safe and effective. 

A mix of filtration, displacement or personal air supply, ultraviolet germicidal irradiation, economizing and energy recovery, tailored to specific project constraints and controlled by advanced building automation systems, can yield high performance at a fraction of the price of solely providing more outdoor air.

Simply monitoring indoor air quality and displaying sensor readings to the public is a great first step. On its own, this can alert facility managers to take action when problems arise and aid occupants’ decision-making based on their personal risk tolerances.

It is also imperative that this conversation is taken beyond the scope of design alone. As leaders in the mechanical contracting industry, we must provide appropriate training to operators and technicians whose day-to-day work puts them in a prime position to recognize red flags in HVAC systems and intervene. They are the foot soldiers who ensure that our systems are properly controlled, provide the necessary airflow and filtration, and are free of stagnant water and mold.

In the race to create the most efficient, safe and healthy spaces, wouldn’t you rather have your building in the lead? l

Bryan Cummings, Ph.D., spent seven years as an indoor air quality researcher at Drexel University prior to joining Harris as a senior building environmental science engineer. He currently leads computational fluid dynamics simulations and analysis as a member of the Harris Design Studio.

Jenni Hermann brought her 20 years of experience in the HVAC industry to Harris when she joined several years ago. Today, she combines that extensive expertise with a deep passion for identifying, optimizing and upgrading indoor air quality solutions for commercial spaces.