Dust Management

The idea that environments are circular loops of production and consumption has been central to recent and ongoing aspirations toward restoring and maintaining ecological balance. In the 1960s and 70s, scientists James Lovelock and Lynn Margulis put forth an influential theory of homeostasis, which characterized the Earth as a complex system that maintains balance through interdependent inputs and outputs of energy.11James E. Lovelock and Lynn Margulis, “Atmospheric Homeostasis by and for the Biosphere: the Gaia Hypothesis,” Tellus 26, no. 1–2 (1974): 2–10. Termed the Gaia hypothesis, their theory asserts that Gaia (a name for the earth with origins in Greek mythology) has upheld its conditions of stability and habitability due to the coevolution and self-regulation of environments and organisms throughout Earth’s deep history. In their account, no organism can be isolated as a singular actor without an effect on its environment. To support this assertion, proponents of the Gaia hypothesis might cite the example of vibrant marine life in the north Pacific off the coast of Alaska and British Columbia, which are fed by nutrient-rich glacial dust blown from inland mountain ranges.22See Kent Moore, Clouds and Complexity: Viewing the Earth from Space, Fig. 2, p. 13, in SDUK 02. In this instance, an ecosystem arises from particular climatic conditions, and harmonious exchanges occur over a broad and diverse geographic area.

In this Alaskan example, glacial dust plays a distinct role in the ecosystem, even if its scope and range is dictated by wind and weather. But in many cases, dust challenges the concept of homeostasis. It eludes linear or circular exchange; as literary scholar Steven Connor writes: “Dust is amorphous, without form and almost void. […] Dust can get everywhere, insinuating itself into every crevice. This makes it a medium of transformation and exchange. Almost without qualities itself, dust has the quality of qualitylessness, the virtual virtue of transmitting the virtues of other substances.”33Steven Connor, “Pulverulence,” Cabinet Magazine 35, Fall 2009.

Dust’s unpredictability has been exacerbated in important ways by climate change, as when drought and unsustainable farming practices release more dust into the atmosphere. Increased dust can enrich marine ecosystems, stimulating growth; or it can settle on glaciers and quicken snowmelt by absorbing more solar energy.44Jim Robbins, “Climate Connection: Unraveling the Surprising Ecology of Dust,” Yale Environment 360, 30 November 2017, https://e360.yale.edu/features/climate-connection-unraveling-the-surprising-ecology-of-dust. The “surprising ecology” of dust is an ambivalent part of ecosystems at a global scale.55Ibid. This very scope is underscored by the recent finding that dust from the Gobi desert serves as a key source of phosphorous for California redwoods.66Aciego, S. M. et al, “Dust Outpaces Bedrock in Nutrient Supply to Montane Forest Ecosystems,” Nature Communications 8 (2017), Article 14800.

As the ecologies dependent on—and marred by—dust can suggest, dust control and containment are unattainable at an atmospheric scale. For engineers tasked with managing dust resulting from industrial processes, similar challenges exist. “Fugitive” dust escapes into the atmosphere as an externality of production. Externalities are waste by-products external to “core” production processes, and as such they disrupt neat, circular geometries of production and consumption. They leak out in all directions, scattering and diffusing, unsettling inside and outside.

Though we may be tempted to cheer for the fugitive escapee, in the case of fugitive dust, its pollutive effects are profoundly detrimental to air quality. In Mississauga’s Clarkson area, citizen-led efforts have worked to curtail these effects through advocacy, research, and industry co-operation.77See Joy Xiang, This, Too Will Contaminate, p. 21 in SDUK 03. CRH Cement (previously Holcim) has worked at its Mississauga plant since the mid-1990s to mitigate fugitive dust through the installation of over 100 baghouses, which are cylindrical filters absorbing ninety-nine percent of dust produced in cement production.88This discussion of baghouses is informed by conversations with Richard Lalonde, former Environment Manager, CRH Canada Group Inc., Mississauga Plant, during a site visit by Christine Shaw and D.T. Cochrane, December 13, 2017. These baghouses are emptied regularly to feed most of their contents back into production processes.

Baghouses are engineered filters, employing distinct fabrics for their particular operating temperature and usage, with integrated cleaning systems to ensure that, unlike a vacuum, they filter dust constantly without clogging. A baghouse resembles a large funnel, where dust settles at the bottom, and is mechanically shaken to fall from filters at regular intervals. The volume of dust during created during cement production is no small matter: in the disused indoor facilities which pre-existed baghouse filtration at CRH’s Mississauga plant, dust settles thickly on every surface like snowfall.

Inside and outside the core processes of industrial cement production, dust highlights how circular exchange stands as an ongoing aspiration for contemporary economies. CRH Cement and the Region of Peel, each a producer and manager of waste, both share a stated commitment to “circular economies.”99Roadmap to a Circular Economy in the Region of Peel (Region of Peel, 2017); “Circular Economy,” CRH Canada. Per CRH: “The Circular Economy […] looks to move our society from a linear economic system of take-make-waste to one that considers that materials can have a beneficial use beyond their primary purpose. The goal is to minimize the amount of virgin materials and energy entering our production systems, as well as looking for products that can minimize waste at the end of their use to be repurposed or reconstructed into something new.”1010“Circular Economy,” CRH Canada. This goal is an admirable one, symbolized and supported by the baghouse: whereas dust once escaped into local airsheds, through citizen advocacy and industry co-operation, it is now largely recycled back into production.

Transitioning to a more truly circular economy is no easy feat. As any visitor to a waste dump will attest, the dominant forms of contemporary human life fail to balance energy inputs with outputs; waste and pollutants continue to accumulate. Whether or not we accept homeostasis as a naturally occurring phenomenon, climate change alerts us to Earth’s connected systems, of which humans are a part. Human beings have already lived in greater balance with non-humans for thousands of years—and in this light, circular economies endure as a worthy aspiration for resource use. Our conception of circularity must, however, come to acknowledge that fungible matter, like dust, often moves porously through the processes and ecosystems we imagine as closed or stable.