Citizen Sensing: Recasting Digital Ontologies through Proliferating Practices

From the Series: Digital Ontology

Photo by Gerd Altmann.

Citizen sensing is a term that describes an emerging range of practices for monitoring environments through low-cost and DIY digital technologies. From air pollution to the migrations of animals, sensors generate data on any number of environmental phenomena. These practices often bear the promise of making citizens more empowered to act on environmental matters of concern through sensor data. What ontologies—digital or otherwise—might be specific to these citizen-sensing technologies and practices?

On one level, citizen sensing might be considered what Annemarie Mol (2002) has termed an ontology-in-practice. In her account of medicine, Mol emphasizes how ontologies form through practices that generate and sustain multiple sociomaterial conditions. If ontologies-in-practice construct objects and worlds, then what objects and worlds might citizen sensing construct? And how does citizen sensing as an emerging set of practices raise questions about the status of practice-based ontologies when those practices are still in formation? In other words, while the emphasis is often on the ontologies that are made or in the making, how do digital practices—such as citizen sensing—come to solidify as recognizable processes or engagements, such that they are able to generate ontologies? Citizen sensing presents a problem for ontologies-in-practice because it refers to a set of practices yet to be stabilized. The ways in which digital practices are often never quite stabilized, moreover, could point to a salient way in which the digital is formative of particular ontologies as ontologies-in-process.

Citizen sensing might be assumed to draw together citizens, entities to be monitored, environments, data, and politics. Instead, though, research on the Citizen Sense projecthas shown that any stabilized account of the practices of citizen sensing unravels once put to work in particular situations. The monitoring of a particular pollutant known as PM 2.5 with a plug-and-play digital device such as the Speck, which Citizen Sense deployed in a kit given to about thirty participants in fracking-affected northeastern Pennsylvania, quickly became entangled with a range of other practices—digital and otherwise—that would inform the contours of what might typically be identified as embodied skills or relations (Gad and Jensen 2014).

Speck monitoring PM 2.5 in Pennsylvania, Citizen Sense project,

Plugging in a Speck PM 2.5 monitor goes beyond attending to the demands of this particular device. It also entails practical actions that include watching the display monitor that provides real-time counts of PM 2.5 and displays of data collected over the previous twelve hours, logging environmental observations that might or might not explain particularly high readings or spikes in data, uploading data to a platform and examining representations of it in tables and line graphs, comparing data to observations made by other participants in the area, and eventually beginning to assemble the data in such a way that preliminary findings can be communicated.

Monitoring also opens up a cascade of other practices that do not neatly cohere as citizen sensing, including organizing informal and formal community meetings to discuss and compare sensor data gathered across an area, communicating about whether bugs or dust lodged in the optical sensor might be skewing readings, developing protocols to ensure the validity of data, contacting state agencies when particularly high readings register and arranging for site visits, preparing spreadsheets and reports to make stronger claims to state and federal agencies about patterns in air-pollution data, debating regulators who would dismiss the legitimacy of citizen-gathered data, developing further monitoring projects that could involve digital or analog monitoring techniques, drawing on the expertise of other scientists and researchers who might provide competing advice or claims, comparing monitoring data to modeled data and permitted emissions, and situating a loosely defined set of citizen-sensing practices within a larger project of negotiating a more tenable set of relationships with an expanding fracking industry.

What might initially be identified as the specifically digital practice of citizen sensing, located within a particular participant’s use of a device to gather real-time data on air pollution, thus opens out on a range of other practices. While the digital modalities of monitoring that record real-time sensor data might, because of their instantaneousness, seem to make evidence more readily available and, hence, political action more proximate, citizen-generated air-quality data also raises further questions about how to engage with environmental agencies and regulators in order to document claims and make them heard, and to hold industry to account. The citizen-sensing practices for gathering data do not always readily align with political engagement, and the original model of citizen sensing that takes this affordance for granted opens out on a yet-to-be-defined set of practices.

In this respect, citizen sensing points to the ways that practice can remain in formation through relations of subjects, objects, environments, technologies, organisms, and pollutants. Gilbert Simondon (1992) has suggested that ontological privilege is typically afforded to already-constituted individuals, as opposed to ontogenetic processes of individuation. Entities that sense and are sensed enjoy this privilege, as do citizen-sensing practices intended to join up sensors and the sensed. But these ontologies give way to onto-genetic inquiries where stable frameworks of being transform into processes of becoming and where the entities, practices, and milieus that would be joined up in a digital encounter concretize in an actual occasion, rather than an always-available formula for analyzing a world or reality as a distinctly digital ontology.


The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007–2013), ERC Grant Agreement #313347, “Citizen Sensing and Environmental Practice: Assessing Participatory Engagements with Environments through Sensor Technologies.”


Gad, Christopher, and Casper Bruun Jensen. 2014. “The Promises of Practice.” Sociological Review 62, no. 4: 698–718.

Mol, Annemarie. 2002. The Body Multiple: Ontology in Medical Practice. Durham, N.C.: Duke University Press.

Simondon, Gilbert. 1992. “The Genesis of the Individual.” Translated by Mark Cohen and Sanford Kwinter. In Incorporations, edited by Jonathan Crary and Sanford Kwinter, 296–319. New York: Zone Books.