“Once we tightened up the buildings, we further isolated the inside from the outside,” says Dr. Elliott Horner, a lead scientist at UL Environment. “We started trapping what was being produced inside and letting it build up to higher concentrations.” This is especially worrisome in schools because indoor pollutants pose a more severe health risk to children.

“The cloud of smoke which hangs over the best part of Chicago night and day the year round, raining down soot and cinders on the washed and unwashed, is not generated spontaneously in the heavens. It comes from somebody’s chimney.”

This lament was printed in the Chicago Tribune in 1888. Historically speaking, outdoor air pollution has been pretty easy to spot. In those fevered years of the Industrial Revolution, coal smoke blackened streets and buildings. When automobiles commuting from far-flung suburbs became the norm in the 1950s and ’60s, exhaust smog hung thick in the air. To mitigate what would be recognized as a widespread health crisis, the first federal Clean Air Act was passed in 1970.

But these days, we breathe a lot less of that cleaned-up outdoor air than you would expect. According to the Environmental Protection Agency, we spend an average of 90 percent of our time inside—in our homes, in our offices, in our schools. And it turns out that pollution generated inside these buildings, while more difficult to see than coal smoke, poses significant health issues too.

The idea of indoor air quality, or IAQ, isn’t exactly new. In their coal- or wood-heated homes, our forefathers knew the importance of ventilation. Benjamin Franklin wrote about it in the late-18th century: “Another grand mean of preserving health is to admit a constant supply of fresh air into your chamber,” he wrote. “A more sad mistake was never committed than that of sleeping in tight rooms.” And yet tighter rooms became the norm following the energy crises of the 1970s. “People started to tighten up the building envelope to save on energy costs, and that caused all sorts of sick building syndrome-type issues,” says Scott Steady, who manages UL Environment’s GREENGUARD certification program. Asthma, drowsiness, dizziness, headaches, even more serious diseases like cancer have been linked to poor IAQ. Worker productivity, too, was shown to decrease within these types of office environments.

In Franklin’s days there were a limited number of factors contributing to negative IAQ, but the proliferation of synthetic materials and cleaning agents in our modern age has brought more culprits than ever.

The quality of our indoor air depends on an incredibly diverse landscape of factors. Its temperature and composition depends on the number of people working, learning, living, and breathing inside. It contains varying levels of air exchanged with the outdoors. Natural elements, like mold growing behind the walls or radon leached from soil beneath the building, can poison the space. Humans pollute it by using products for our daily lives, like cooking gas, hairspray, or toilet cleaners, all of which contain volatile organic compounds, or VOCs. And synthetic building materials, finishes, and furnishings can off-gas toxins as they dry, age, or react with other substances.

So stop reading. Look around, wherever you are. That wood trim may be treated with urea-formaldehyde or arsenic—both carcinogens. Your wall coverings, furnishings, carpeting, pipes, doors, or windows most likely contain phthalate, a common—and toxic—plasticizer. Your chlorinated roof membrane probably contains dioxin, another carcinogen. From our insulation to our furniture, the materials that have made buildings so much cheaper and more efficient in the past half-century have, to be frank, made us sick.

“Once we tightened up the buildings, we further isolated the inside from the outside,” says Dr. Elliott Horner, a lead scientist at UL Environment. “We started trapping what was being produced inside and letting it build up to higher concentrations.” According to the EPA, concentrations of certain pollutants can be two to five times higher inside than outside, and yet with the exception of state and municipal smoking bans, interiors are, in Horner’s words, essentially unregulated airspace.


New building products and classroom furnishings are helping to keep classroom air clean. Look for products certified through UL Environment’s GREENGUARD certification program at productguide.ulenvironment.com.

UL—or Underwriters Laboratories—was originally founded in the late nineteenth century to test and, later, certify, the fire safety of electrical inventions by patent-happy Americans, but it has spent the past decade expanding into the health and environment frontiers. In 2011, it acquired GREENGUARD, arguably the best-known certification related to healthy products for IAQ. (It is recognized by LEED, Green Seal, Green Guide for Healthcare, Collaborative High Performance for Schools, Green Globes, and more.)

Hundreds of manufacturers are opting in. “We felt that GREENGUARD had the most thorough and demanding process,” says John Fischbach, president of Decca Contract, a Minnesota-based maker of wood casegoods and seating products. “And we wanted to be pushed.” The certification process is straightforward, but, as Fischbach says, rigorous. Here’s how it works.

“First is the manufacturing and documentation review, where we take a look at a product’s raw materials and supply chain,” GREENGUARD’s Steady says. This can be an extensive part of the process for companies with a wide range of product types, sizes, and configurations. While some companies opt to certify an entire product line, others select individual products to test how they sell with the certification attached. A few years ago, having the GREENGUARD mark on your website was somewhat of a novelty, but today, addressing the emissions of your product has become increasingly important if a manufacturer wants to be competitive on a bid. “As people came to understand what the program was about, it became an accepted standard, then it became a desired standard, and then it became a required standard,” says Bill Strickland, the national market manager at Phifer Incorporated, a manufacturer of sun-control products like window shades. “Now I’d say you’d be hard-pressed to find a product in this industry that has not pursued or achieved GREENGUARD certification.” (Read more about Phifer in our Manufacturer Spotlight.)


Phifer’s SheerWeave fabrics were the first window treatment product line to achieve GREENGUARD certification. Read our Manufacturer Spotlight here.

During the next step, a screening test of product samples, the third party’s engineers will warn the manufacturer if it sees anything that would prohibit the product’s ability to earn certification. “At this point, they may go back to the drawing board from an R&D perspective and look at new materials,” Steady says.

Finally, certification is offered to the products that pass. For example, in the furniture category, to achieve GREENGUARD Gold, VOCs cannot exceed 0.22 milligrams per square meter, and formaldehyde concentrations have to be less than nine parts per billion.

It isn’t just a one-time pass or fail. “We ask manufacturers to tell us if there are any changes to raw materials or components,” Steady says, “and then on an annual basis, we go back in and do random recertification testing.”

Upon certification, products are added to UL’s Sustainable Product Guide, a database of GREENGUARD, ECOLOGO (for cleaning products), and otherwise vouched-for products. The free online resource means architects and designers don’t have to reinvent the wheel. They can search UL’s product guide by category, brand, or—helpfully—credits earned within rating systems like LEED, Green Globes, or ASHRAE. The “LEED 2009 For Schools” tag, for example, includes more than 9,500 results, from fiberglass insulation by Guardian to fabric-topped stools by NeutralPosture.

“Architects and designers can save time by taking the documentation right out of our Sustainable Product Guide and submitting it,” says Dagmar Ebaugh, PR and communications manager at UL Environment. With the legwork of drilling down through the product chain out of the way, designers can focus on what they do best: design.


Materials within Perkins+Will‘s Sprout Space—a 1,000-square-foot modular classroom—include Marmoleum flooring made of powdered wood, jute, and linseed oil, as well as FSC-certified, urea-formaldehyde-free wood treatments. They were vetted through an open-source website called Transparency that Perkins+Will launched in 2012.

A preliminary study published in Indoor Air in 2006 reported that high ventilation rates in classrooms correlated with a 14–15 percent increase in standardized test scores, bringing the topic of IAQ directly in front of educators. Studies also show that because children have a higher heart rate and breathe higher volumes of air relative to their body size than adults, indoor pollutants pose a more severe health risk. 

So ventilation is a very large tip of the iceberg for healthy classroom environments. And it happened to be the issue that Perkins+Will’s Allen Post first noticed when he stepped into a mobile classroom building for the first time. “I was just—” Post pauses, looking for the right word. “Blown away. And shocked. All of the windows had been spray-painted over. There were holes in the floor and even in the door. It was moldy, overcrowded, dark, and loud. I could not imagine learning in that classroom. When you see that, it inspires you to make it better.”

The experience, says Post, who has been with Perkins+Will’s K-12 education group for the better part of a decade, motivated his team to create a solution to the hundreds of thousands of mobile classrooms across the country that have, often because of budgetary constrains, long outlived their intended period of use and become unhealthy environments.

That solution was Sprout Space, an approximately 1,000-square-foot modular classroom building that won Architecture for Humanity’s Classroom of the Future award in 2009. Its windows, and even a few walls, are fully operable, allowing huge swaths of fresh air in. One of the marker boards is installed on the exterior to create an outdoor learning space.

The building materials—from Marmoleum flooring made of powdered wood, jute, and linseed oil, to FSC-certified, urea-formaldehyde-free wood treatments—were vetted through an open-source website called Transparency that Perkins+Will launched in 2012. The site features a “precautionary” list with known and suspected risk factors of 25 categories of chemicals.

But building owners have to think holistically. A perfect building structure, with low-emitting ductwork, flooring, and insulation, will fail at healthy IAQ if it’s filled with high-emitting desks, chairs, lockers, activity mats, and shelves. “A lot of times, clients don’t ask us to be involved in the furniture selection,” Post says. “So they come in after we’re gone and put in furniture that has a lot of the contaminants … that we worked so hard to keep out of the classroom.”

Which is why Perkins+Will teamed up with School Specialty, a full-service educational products company, for Sprout Space. “You want a balanced learning environment that meets total need,” says Jason DeWeerd, the director of sales at School Specialty. “Not only from a structural standpoint, but also a furnishings standpoint.” The company’s Projects by Design division tapped some of its key forward-thinking manufacturing partners, such as Bretford and Mooreco, to outfit the space with GREENGUARD-certified classroom furniture, marker boards, storage, and more.


The Puzzle Table from VS America features a powder-coated steel frame and durable melamine-resin-coated chipboard. It can stand alone or be pieced together.

In another educational environment with cutting-edge health strategies, VS America provided all of the furniture for Aspen Country Day School’s recent renovation and new 18,765-square-foot classroom building. While mitigating product emissions, the project also addresses how furniture design and layout can impact learning.

“VS has created chairs that allow kids subtle motion, rather than fighting with the static chair,” says Sue Walker, VS America’s Rocky Mountain regional manager. Some studies have shown subtle motion can actually help a child to focus while mitigating negative health issues associated with inactivity. The sturdy, long-lasting products designed by VS—which is relatively new to the US, but was founded in Germany more than a century ago—are also designed to hold up to the beating they can take in the classroom. “We have one desk product consisting of sawdust, which is pressed and heated so the resin in the sawdust binds it together,” Walker says. “No off-gassing, no glues, no plastics. And you can beat it with a baseball bat.”

In addition to obtaining GREENGUARD certification for its furniture, VS achieved a stringent Level 2 certification through the Business and Institutional Furniture Manufacturers Association (BIFMA) for about 50 of its products. Level is to furniture what the Living Building Challenge is to the architecture industry, with evaluative categories of materials, energy and atmosphere, human and ecosystem health, and social responsibility. Level also offers a database of its certified furniture online.

The indoor air around us may not be federally regulated yet, but in the past several years, attention to indoor air quality has become pretty much standard. There are plenty of available resources to help along the way, from UL Environment’s Sustainable Products Guide and Perkins+Will’s open-source Transparency to the Red List of materials compiled by the International Living Future Institute.

Healthy indoor environments make sense at the very zenith of the idealism scale—because if we’re not protecting our children from schools that make them sick, what are we doing?—but they can also be a straight-edged practical matter for those who care about liability, longevity of investments, responding to client desires, test scores, or employee productivity.

So there’s really no excuse. Like coal smoke and car smog, indoor air pollution “isn’t generated spontaneously by the heavens,” but primarily by the building industry. Let’s clean it up a little.