Dietmar Offenhuber

Ozone Tattoo

Plant bed & tent, soil, tobacco plants, snap bean plants, fumigator
2’ x 4’ x 6’
Installed on the Cambridge City Hall Annex plaza Project Partners: Dr. Vehram Elagoz, Lesley University, Dr. Kent Burkey, USDA ARS Maryland


Climate change, environmental pollution, and social justice are closely intertwined. Their implications are not immediately obvious. Rising temperatures, for example, will also increase ground-level ozone pollution. Researchers estimate that the increasing intensity of summer heat waves will lead to a 70-100% increase in ozone episodes,[1] which cause respiratory and cardiovascular diseases in humans and extensive damage to plants. Ozone pollution, however, is invisible and for non-experts difficult to measure. Both climate change and air pollution disproportionally affect economically disadvantaged populations living in areas exposed to greater levels of these environmental threats. Climate change will affect Cambridge not only through flood surges or warmer temperatures but also through worsening air pollution that causes respiratory and cardiovascular diseases.

Ozone Tattoo uses plants as bio-indicators to visualize ozone pollution. It is based on the established citizen science approach of planting ozone gardens, which allow communities to monitor pollution by observing plants that are sensitive to ozone and react with visible symptoms. To make the damage to plants more legible, we developed the novel method of ozone tattoos. The tattoos are damage patterns on the surface of the leaves, created by localized exposure to ozone. These damage patterns act as a biological visualization that allows us to decode the impact of the pollutant through visual comparison with the healthy portions of the leaf.

One of the indicator plants used in the project, the tobacco plant, has historical significance for Massachusetts and its history of industrialization. Until the early 1920s, western Massachusetts was a center of tobacco production, the source of high-quality cigar wrappers. One factor that ended this thriving industry was the adverse effect of ground-level ozone resulting from industrialization. Tobacco plants are highly sensitive to ozone and show visible damage even at low concentrations. This sensitivity makes the plants an excellent bio-indicator that is often used in ozone garden projects. But tobacco is not the only bio-indicator suitable for measuring ground-level ozone. Snap bean plants, cone flowers, and milkweed are extensively studied by plant biologists and are frequently used in community ozone gardens.

Ozone Tattoo is part of a larger effort to seek alternative forms to visualize invisible environmental threats. Much of what we know about our environment comes from digital sensors and is presented in generic data visualizations. How these abstract representations relate to the material environment, however, is not always clear.

In contrast, Ozone Tattoo is based on a material understanding of data, embodied in the visible impacts of the phenomenon itself. It allows us to understand data as something physical that surrounds us and can be interpreted. Ozone gardens and other citizen science projects can teach us how to care for our local environments and engage in a critical inquiry of environmental information. Beyond merely delivering information, the project aims to facilitate a deeper understanding of the material impact of climate change on Cambridge, its plants, animals, and communities.

[1] See

Special thanks: Dr. Kent Burkey, Plant Physiologist USDA; Prof. William Manning, UMass Amherst; Northeastern University


About the Artist:

Dietmar Offenhuber is Associate Professor at Northeastern University in the areas of information design and urban affairs. He holds a PhD in Urban Planning from MIT. His research focuses on the relationship between design, technology, and urban governance. Dietmar is the author of the award-winning monograph “Waste is Information” (MIT Press) and has published books on urban data and related social practices. He also works as an advisor to the United Nations Development Programme.

Related City resources

Sustainable Transportation Planning: Cambridge is flat and compact, with a mixture of housing, retail, and other businesses and institutions, making it is easy for most people to make at least some of their daily trips without driving. As roads are reconstructed, we look for ways to make them “complete streets” -- streets that work well for all modes of travel. You will see facilities that encourage walking, such as sidewalks on both sides of virtually all streets, short blocks, frequent opportunities to cross the street, and signal timing that favors pedestrians. You'll see many bicycle facilities, including bike lanes, bicycle facilities separated from moving traffic ("cycle tracks"), and plentiful bicycle parking. Traffic calming projects are designed to keep automobile speeds down, making our streets safer for all users.  

Efforts to make our city easier to navigate without driving have paid off.  About 30% of our households do not own cars, relying on other options that the city provides.  Many other households do not use their cars on a daily basis. Cambridge residents are among the least car-dependent commuters in the country. Among small cities we have the highest percentage of residents commuting by means other than driving. Counter to the trend elsewhere in the state, car ownership and trips have declined in Cambridge over the last ten years.