As if the climate crisis were not enough, scientists have identified another atmospheric threat of our own making: air pollution from microplastics, small particles derived primarily from waste plastic.
Researchers at the University of Auckland recently published a study revealing that 74 metric tons of microplastics fall out of the sky above the coastal New Zealand city every year. This quantity translates to more than three million plastic bottles’ worth of polymers, with eight common plastic types, including polyethylene (PE), polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), and polycarbonate (PC), identified among the samples. The daily average number of individual microplastics—defined as 5 mm or smaller in length—amounts to 4,885 per square meter of air. Although the team theorizes that Auckland receives many of its particles due to wave action breaking down marine plastics, the presumption is that this is a ubiquitous problem.
This jarring news brings heightened alarm about the challenges associated with microplastic waste. Although there has been growing awareness concerning the proliferation of microplastics in water and food, the realization that we are breathing plastic is utterly dismaying. The scientific community knows little about the effects of microplastics on humans and other species at this time, and there is renewed urgency to learn more. Influences include injuring cells and triggering inflammatory reactions, and there could be many other detrimental outcomes.
How should the architecture, engineering, and construction community respond to this growing crisis? We can begin by looking at the increasing prevalence of plastics used in building design and construction. By 2017, the global market for plastics in buildings was more than $102 billion, with an anticipated growth of 7.3% by 2025. The construction applications representing the largest market share include pipes and ducts, insulation, roofing, windows, and wall coverings. PVC is dominant, with more than 40% of the market, followed by PS at 15%. Other common polymers used in buildings include PE, PP, and polyurethane (PU), the fastest-growing market segment. According to Finland’s Ministry of the Environment, construction accounts for approximately 20% of all plastics use.
The Auckland findings provide preliminary insights about which polymer types are most problematic. In their observations of microplastic samples, the researchers found the greatest concentrations to be types PE, PC, PET, and PVC—in that order. PE comprised nearly 40% of the samples’ total mass, whereas PVC occupied approximately 10%. In terms of world production, the most common polymers ranked by mass are PE, PP, PVC, PS, PU, and polyethylene terephthalate (PET). Note the differences between the lists: PE appears at the top of both, as we might expect, but PC jumps ahead of the more common PVC and PET. Does this mean that PC is intrinsically more detrimental? Meanwhile, PP and PS comprise relatively small percentages of the total microplastic sample mass despite their large share of global polymer production. Are these plastics “safer” bets?
It is important to note that these points are based on very limited data. We do not know if the team’s findings have universal applicability. Furthermore, the researchers did not classify all polymer types in their study, so we should avoid jumping to conclusions. Nonetheless, the discovery raises several questions that should direct future studies, including: Do some polymers generate more significant quantities of microplastics than others? Do microplastics from some polymer types pose more severe health problems than other types? What are the most common causes of microplastics generation (e.g., UV degradation, abrasion), and how can they be avoided? Do some product applications generate measurably larger quantities of microplastics than others (e.g., single-use bags versus pipes)? What percentage of microplastics do building materials contribute versus consumer products? Are their particular polymer types or processing methods that limit the future generation of microplastic particles within a safe range for living organisms? (What is the safe range?)
The discovery that the sky is effectively raining plastic adds further bad news about this inherently problematic material. After all, polymers’ contributions to greenhouse gases, the Great Pacific Garbage Patch, endocrine disruption, and the fossil fuel economy represent concerns of sufficient severity to question our continued use of plastic. As a result, a growing number of environmental organizations—such as Vermont-based Beyond Plastics, which notes that the American plastics industry contributes a minimum of 232 million tons of CO2e gas emissions per year—recommend an end to our plastic diet.
And yet, such a goal seems Sisyphean. Plastic is ubiquitous and inextricably tied to nearly every industry and market sector—including building construction. Curtailing our use of this material is not a likely or practical scenario, at least not in the short term. Instead, a more productive strategy is to consider different types of plastics, as well as their processing methods and applications, from an end-of-life perspective. For example, there may be particular formulations of bioplastics (such as 100% cellulose-based polymers) that might negate the concerns about petroleum-based plastic, including the generation of harmful forms of microplastics (more studies are needed to validate this notion). Scientists might also determine, as suggested above, that some common polymer types contribute more damaging microplastic particles than others—which could motivate a market-based response. And some plastic types and applications—such as upcycled building products—might be deemed entirely safe under controlled circumstances.
Much work lies ahead for the scientific community to address these and other hypotheses. In the meantime, architects should look more closely at the specification of plastic products in light of the recent University of Auckland report. Humanity’s current epoch has been nicknamed “The Plasticene,” or the Age of Plastics, based on the world-shaping influence of polymers. Let us aim to mitigate the damaging effects of this era as we reshape today’s plastic into a future substance that is inherently healthy for all species.
The views and conclusions from this author are not necessarily those of ARCHITECT magazine or of The American Institute of Architects.
Read more: The latest from columnist Blaine Brownell, FAIA, includes lessons from India about confronting a warming climate, the future of insulation, boosting the insulation capacity of windows, and the impact of building codes on the fragility of the built environment.