Custom Filtering

A new air purifier looks to provide fresh air in offices on a desk-by-desk basis.

Last February inside an office in Manhattan, against the backdrop of Garment District traffic noise and the squeals of a not-so-distant table saw, industrial designer Stefan Spoerl and consultant Frank Barnes were giving a demonstration of air purifiers. Their first bullet point: noise pollution. Spoerl turned on the switch of a popular air purifier. On turbo setting the device sounded remarkably similar to the roar inside an airborne jetliner. Barnes shouted a running commentary: “We have an industry standard, the Clean Air Delivery Rate [CADR]. You put your unit into a test chamber and it will measure how much air you’re moving and how efficient the cleaning is. The multiplication of those two is your CADR. The higher that rating, in theory, the more people will want to buy it. The problem is they don’t take into account noise. So a 300 CADR unit sounds about as loud as a vacuum cleaner.”

Spoerl turned off the unit and turned his attention to a knee-high wooden box in the corner of the meeting room, a prototype of a room-size air purifier he has been working on at Humanscale, the ergonomic-office-equipment maker. All this time, the box had been silently issuing a steady stream of cool, and presumably clean, air.

Spoerl and Barnes are part of a Humanscale team developing a new line of air purifiers aimed at providing clean air in offices on a desk-by-desk basis. Clean air is a surprisingly precious commodity in offices. A seeming paradox in the history of allergic diseases, including asthma and hay fever, is that as public pressure on governments has brought about an improvement in outdoor air quality, the number of people suffering from allergic reactions has increased. According to some sources, about 25 percent of Americans now suffer from allergies. In the second half of the twentieth century, allergists and researchers began looking indoors for an explanation and uncovered a fetid breeding ground in the modern interior: better-insulated energy-efficient buildings, air-conditioned and humid spaces where air is constantly recycled, and tufted carpets that conceal dirt provide perfect incubators for dust mites, bacteria, and mold. Today the litany of allergens has been joined by a host of other potential culprits: off-gases, nanoparticles, volatile organic compounds exuded by our fixtures and furnishings—by the stuff that surrounds us. “The greater anxiety now is not the big dirty smokestacks and domestic chimneys,” said Mark Jackson, a historian of medicine and the author of Allergy: The History of a Modern Malady, in a 2004 radio broadcast. “It’s the invisible components in the air that we breathe.”

If design is partly to blame for the foul air of the modern interior, it can also be part of the solution. The Environmental Protection Agency (EPA) is working with professional organizations including the American Institute of Architects to publish a best-practices guide for design and construction. The agency acknowledges, however, that “people generally have less control over the indoor environment in their offices than they do in their homes.” Humanscale’s line of portable air purifiers, to be launched early next year, aims to redress that. “We’re all about creating a healthy, comfortable place to work, and air quality is part of that,” Humanscale founder and CEO Robert King says. “I’ve been thinking about it for fifteen years, but we didn’t want to get involved unless our product takes the category to another level.”

King aims to reach that new level with a technology developed in Sweden by Polish-born inventor Andrzej Loreth, whom Barnes introduced to Humanscale in 2006. An electrical eng­ineer by training, Loreth has labored for about 25 years to create a noiseless, efficient air purifier based on the controversial Electrostatic Precipitator (ESP) method, which traditionally uses a high-voltage “corona” wire and a magnetized metal plate first to charge and then to attract airborne particles. This method does not require a powerful fan but has the downside of creating ozone as a by-product of the charging process. Ozone is useful in the earth’s upper atmosphere for protecting us from ultraviolet light, but at ground level it is an irritant known to damage both human and animal respiratory systems. Humanscale’s air purifier uses the ESP principle, but with components that are substantially reconfigured from those of its competitors. In a phone interview from Sweden, Loreth, who owns nine U.S. patents on the invention, explained that his system uses a large ionization chamber for charging the particles and a washable coated-paper filter—concertina-folded like a fan—to catch the particles over a large surface area. This arrangement means that the corona wire can operate at a much lower voltage than rival ESP systems, resulting in a minimal by-production of ozone. The federal government sets a safe ozone limit at 50 parts per billion, and in tests Loreth found that his device produced about 0.04 parts per billion. “It doesn’t make sense to even measure it,” he says. “To be honest, as an engineer I can’t say it’s no ozone, but the level is so low it does not influence the consumer or the environment.”

In launching the new product line, however, Humanscale will enter a perilous market quite different from its usual field of play—and one rife with mistruths. Last December the independent nonprofit watchdog Consumers Union published a Consumer Reports review of air purifiers, bluntly stating that there is “little definitive medical evidence that purifiers help relieve respiratory symptoms. Some may pose a threat even to healthy users.” The report attacked as “not acceptable” a type of purifier known as the “ozone generator,” which purposely adds ozone to the indoor environment—and lots of it. According to the report, both the EcoQuest Fresh Air purifier, which claims to use “space-certified” technology “used to scrub the air inside spacecraft,” and the Eden Pure Area, which similarly boasts technology “used by the federal government to purify air in the Space Shuttle,” produced ozone in excess of the EPA limit, even on low settings—and neither is used by NASA.

Consumer Reports editor Celia Kuperszmid Lehrman recommends buying filter-based whole-house or portable purifiers rather than electrostatic precipitators that produce ozone even as a by-product. “Why add ozone to the air when you can clean it without?” Lehrman says. Dr. Richard Shaughnessy, director of the University of Tulsa’s Indoor Air Program and one of the report’s external consultants, raises the additional specter of ozone’s volatility. It reacts with many of the gases released by household products, including air fresheners, to form ultrafine particles and formaldehyde. “In the past ten to fifteen years, this research has really accelerated,” says Shaughnessy, who adds that ozone has been linked to increased mortality rates even when present in low rates of ten parts per billion. “The EPA recently lowered the [permissible] ozone standard outdoors, but we spend about ninety percent of our lives indoors.”

Humanscale’s Tom Revelle is undaunted, pointing out that his company has once before expanded its field of operation with a product that went against convention, when it added the Freedom task chair—with its heavily reduced array of user controls—to its line of ergonomic monitor arms and keyboard trays. “We believe so much in this technology that our first course of action is, We have a lot of education to do. We’re used to that. A lot of our customers wouldn’t let us in the door without a recline lock on our chair.” He adds, “Ninety percent of a company’s building costs are people. If you can come up with a product that prevents people from having sick days or allergies, the cost savings are huge.”

Shaughnessy says the problem is not with ESP technology per se: “There’s a broad class of manufacturers using this method that has a neglible increase in the amount of ozone in the environment. It’s a matter of sorting that out.” He explains that the lack of medical evidence supporting the use of air purifiers is due to poorly designed studies: there are air purifiers that have been shown to “significantly reduce particulate matter” but have not been linked to medical studies of the impact of such a reduction on occupants. “We have a disconnect there,” Shaughnessy adds. “It’s not that there’s no benefit to be had; it’s defining the process and removal mechanisms, whether there’s an improvement, and what’s the reduction. The huge problem is that there’s such diversity of cleaners on the market, and some are very ineffective.”

The potential gains for Humanscale in launching a product aimed primarily at the office market are equally huge. Last year consumers in the United States spent $554 million on air purifiers, according to market researcher Synovate. Since air-purifying units are mostly purchased for the home, Human­scale sees a large potential market for office and home-office sales. To help distance itself from the quacks, the company has invested development funds into producing product forms that aim for low visibility and high flexibility while maximizing the effects of the technology. Spoerl and mechanical engineer Brad Augustine have worked with Loreth to test and develop three versions of the product: a room-size unit expected to clean up to 450 cubic feet per minute (cfm), a circular 70-cfm desktop unit designed to create a “clean-air zone” for up to three people, and a small 40-cfm unit that would clip onto desk edges or monitors to create a “personal clean-air zone.”

The idea of having a device clean only the air area around your desk area seems strangely selfish, but Revelle finds a parallel in the relation between task and ceiling-mounted lighting, with the new Humanscale products perhaps used as a supplement to filters attached to the air-conditioning system. The company’s research has revealed that office workers do indeed spend an alarming amount of time in one precise spot. The circular unit, which proved to have a remarkably effective distribution in Humanscale’s tests, might also be hung from the ceiling, opening up the possibility of applications in other workplaces: cleaned air for sleeping patients in hospitals, for example. “The most efficient distribution of air is top-down,” Barnes notes.

Aesthetically, the design team under King’s leadership has cleaved to the old Modernist dictum of form following function, the interface pared down to a switch and a single green LED light that turns red to indicate when the filter needs cleaning. The design language is not consciously related to the distinctive forms of Humanscale’s Freedom and Liberty chairs, designed by Niels Diffrient, but Spoerl finds one pleasing parallel to Diffrient’s approach: “In the same way he’s reducing the knobs on a chair, we’ve reduced this to one switch.” The overall goal is for products that look “clean, fresh, and unique,” says Spoerl, whose sentiment is echoed by Barnes. “The industry has in recent years been filled with charlatans,” Barnes says. “We have to get people to take a fresh look at this thing.”

Beneath the surface of this language of cleanliness lies a whole cultural history of collective anxiety about an approaching allergy pandemic. Mark Jackson notes that as the range or knowledge of potential allergens increased in the late twentieth century, so too did the frequency, severity, and complexity of allergic reactions, culminating in media reports of victims of “total allergy syndrome,” memorably dramatized in Todd Haynes’s chilling film Safe, about a woman suffering from chemical sensitivities who becomes alienated from her husband and falls prey to a New Age “caregiver.” The roots of this character type can be traced to the mid-twentieth-century American housewife who, liberated from cleaning chores by inventions like the vacuum cleaner, suddenly found herself bombarded by a new advertising pitch for and cultural obsession with domestic hygiene and spotless interiors. At that point, Jackson says, about one in thirty people in developed countries was suffering from symptoms of allergic reactions.

Today’s allergy treatments, hypoallergenic products, and air purifiers are marketed with a new twist on this ascetic impulse, bound up with a return-to-Eden marketing mythology that plays on anxiety about modern civilization. Our fears may be well placed—toxic manufacturing, unsustainable agriculture, and ironically, improved standards of domestic hygiene (which may have lowered our resistance) are all culprits—but Jackson maintains skepticism about the gravity of the threat. “It is possible,” he writes in Allergy, “that the global epidemic of allergies carefully charted by allergists and epidemiologists, sen­sationally revealed by the media, and deeply dreaded both by patients and by national and international health organizations was, in some senses, imagined.”

This is not to downplay the severity of the effects of allergies, however. Asthma affects more than 22 million Americans, according to the Centers for Disease Control and Prevention, including 6.8 million children, with the largest growth in asthma cases among those under five. To combat the problem, Loreth has developed a system using the same filtration engine over the vents where air-conditioning and heating systems blow air into a room, in particular a classroom. “Children are a group more dependent on clean air,” he says, citing Scandinavian studies linking good air quality with better learning skills.

It is worth remembering at this point that air purification is only one portion of an indoor pollution problem. Architect Jim Burton, who studied under the late Samuel Mockbee, evokes the message from Paula Baker-Laporte’s 1998 book, Prescriptions for a Healthy House: “elimination, ventilation, and filtration.” Air purifiers filter out some contaminants but not the sources of the problem, be it off-gases, dust, or a cat. “Source control is the only way to take care of things,” Shaughnessy says, advising, in the latter case, removal of cats.

Humanscale’s portable system might then be seen as a Band-Aid on a bigger trauma, creating a drop of clean air in indoor smog. But Loreth sees it as a supplement to a larger system. “There are two problems: the air coming through the systems is not clean, as particulates are coming through the vent systems; second, people and furniture also create particulates, so for good air quality you need to put it in the vents and as a stand-alone unit.”

Whether or not we are approaching a situation when, as the Brussels-based UCB Institute of Allergy warns, “in thirty years’ time everyone may be allergic,” demand for design solutions that take into account indoor air pollution will surely continue to increase. In Burton’s view, air purifiers have a bigger part to play in cleaning air. He hopes that buildings using fresh-air induction ports and filtration technology with solar and wind power might eventually act as “lungs for a city, cleaning the air out.” Until then, remember to throw open the windows every now and then.

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