A smoggy Shanghai skyline.
Blaine Brownell A smoggy Shanghai skyline.

During a study-abroad tour of China that I led in May and June through the University of Minnesota’s School of Architecture (read more about the trip here and here), one topic, aside from architecture, that my students and I discussed regularly was air pollution. Although we were in southern and central China, which are less affected than Beijing and other northern cities, we often found ourselves in a murky atmosphere. For three weeks, we rarely saw blue sky even on sunny days, and the air imparted a palpable thickness. We checked the country's Air Quality Index (AQI) daily via mobile app for the local forecast—especially after a bout of intense allergies sent me to a local pharmacist. This led us to question how we as architects and designers can counter such an ever-present problem.

Air pollution influences not only our physical health but also our experience of the built environment. Buildings and landscapes become soft and gritty, losing their clarity, sharpness, and color behind a veil of smog. The azure backdrop that is beloved in architectural representations is rarely witnessed. Rather, gray predominates, at times accompanied by brown. Despite this reality, blue sky persists in renderings of projects in China.

To be fair, Chinese cities are not the only ones wrestling with air pollution. In April 2014, the World Health Organization announced that New Delhi had the worst air quality of more than 1,600 cities worldwide, with the highest average level of PM2.5 particles (fine particulate matter of 2.5 microns or less, such as dust and soot), from 2008 to 2013. Additionally, more than 70 cities—including Karachi, Pakistan; Doha, Qatar; and Cairo, Egypt—reported greater levels of PM2.5 particles than Beijing for the same period. Poor air quality often results from dirty power generation, industrial pollution, crop burning, and automotive emissions, but it can also stem from natural phenomenon such as wind-blown sands or forest fires (though even these may be blamed partly on humans' Anthropocene influence).

"Buildings are significant repositories and gateways of resource flows and as a result they are culpable in the air pollution problem—although the connection is often difficult to measure."

No one place experiences good air quality 100 percent of the time. We are lucky to have relatively clean air in North America, yet a recent conflagration of wildfires in Canada resulted in a temporary “airpocalypse” there and in the northern U.S. On July 6, an acrid cloud from the fires passed through the Twin Cities, where I live, sending the AQI soaring past 180. (Developed by the Environmental Protection Agency, the scale runs from 0 to 500 with levels at or below 100 meeting the standards of the Clean Air Act.) That day I received an email from a Vancouver-based colleague who reported that the sky over his part of British Columbia looked like that of Mars. Although atmospheric conditions have since improved rapidly in our respective regions, the fires were a sobering reminder that other parts of the globe encounter similar levels of pollution on a frequent basis.

How can architecture address the problem of air pollution? Buildings are significant repositories and gateways of resource flows, and as a result they are culpable in the air pollution problem—although the connection is difficult to measure. Architects can make collective choices that will have a broad impact in aggregate, such as specifying materials from nonpolluting manufacturers or obtaining electricity from clean sources. However, local decisions that can deliver tangible results are much more satisfying. Lately, air pollution has received increased media attention​ worldwide, with a proliferation of design proposals intended to address the problem. Considering these and other architectural strategies holistically, below are five approaches that architects can take:

OMA's CCTV Headquarters, in Beijing.
Blaine Brownell OMA's CCTV headquarters, in Beijing.

The first: denial. Although each structure is part of an atmospheric commons, air pollution is often considered to be someone else’s problem. Architects continue to specify conventional materials and systems that meet minimum code requirements. Shiny envelope products such as glass and aluminum are as standard as the blue sky in renderings. In heavily polluted cities where a building’s appearance is profoundly influenced by recurring smog, this passive form of denial is at best naïve and at worst negligent. In a high-profile, award-winning project like OMA's CCTV headquarters, in Beijing, the result ​can be disheartening.

The second approach is grudging​ recognition. Architects acknowledge the need for better indoor air quality (IAQ) standards and general improvements to AQI. As a result, they select products with greener manufacturing and supply chains, and specify façade materials after studying how existing, neighboring buildings are affected by local pollution. Although this strategy does little to improve matters, it does less to exacerbate them.

The vegetated facade at Perkins+Will's Shanghai Natural History Museum.
Blaine Brownell The vegetated facade at Perkins+Will's Shanghai Natural History Museum.

The third approach is intensified control. In polluted environments, architects design or retrofit buildings to maximize occupant health in spite of the outdoor conditions. This common strategy employs separation and purification: The introduction of so-called fresh​ air is minimized and heavily filtered, and the building envelope is treated as a hermetic seal between occupants and the outside world. This approach benefits IAQ at the expense of distancing occupants from the outdoors.

The fourth approach is remediation. In this case, buildings assume a role in improving interior and exterior environmental conditions. Architects specify self-cleaning materials and photocatalytic coatings that measurably reduce local concentrations of airborne particles. Vegetated surfaces are employed to clean and oxygenate the air, and fan-assisted systems like the Active Modular Phytoremediation System (shown below), co-developed by the Center for Architecture Science and Ecology, in Troy, N.Y., and Skidmore, Owings & Merrill, use ventilation to increase the efficacy of the process. Although remediation is a commendable—even altruistic—strategy, it may be difficult to justify the elevated expense for what constitutes a negligible influence on a broad scale.

The Active Modular Phytoremediation System uses plants to remove toxins from mechanically supplied air.
Center for Architecture Science The Active Modular Phytoremediation System uses plants to remove toxins from mechanically supplied air.

The fifth and final approach is provocation. Taking advantage of their buildings' public visibility, architects pursue projects as opportunities for design activism. They purposefully select materials and design approaches that amplify local climatological circumstances for noticeable visual effect. One example is international studio R&Sie(n)'s 2002 Dustyrelief / B_mu project in Bangkok, whose electromagnetically charged skin is designed to become fuzzy over time by attracting dust particles from the surrounding space. Another example, this time in fashion, is London designer Lauren Bowker's PdCl2 jacket (shown below), which turns from yellow to black in the presence of atmospheric carbon. Though eye-opening, such strategies do little to improve their users' physical health (although designers could argue that, over time, they encourage improved standards for all).

Of these strategies, there is no single winner. The last three approaches are obviously more desirable, as they are responsive to the problem of air pollution. Yet each has its own benefits and drawbacks, and the ability to quantify their positive effects decreases dramatically from numbers three to five. Nevertheless, architecture should play a role in improving the AQI. As urbanization and industrialization continue to increase, air pollution will worsen in direct proportion to this growth unless dramatic countermeasures are taken. Government regulations and incentives will continue to play a critical part in addressing the problem, and architects can be great advocates for political change. Architecture itself, however, is the best medium for this advocacy because each building tells its own story—and even the smallest changes can collectively produce tangible improvements.