Food Access: A Time Issue

In the US, the rising obesity rate and obesity-related comorbidities, such as cardiovascular diseases and Type-II diabetes, have drawn health geographers’ attention. It is generally understood that the lack of access to healthy food provisioning, such as grocery stores selling fresh fruits and vegetables, is driving this obesity crisis. Under this context, the US Department of Agriculture (USDA) Economic Research Service (ERS) develops an inquiry tool, the Food Access Research Atlas (1), generally known as the “food desert locator,” to highlight areas with both low-income and limited access to grocery stores. The tool also incorporates other variables, such as car-ownership, to identify communities at risk of food insecurity.

“Food deserts” identified by the USDA Food Access Research Atlas (1)


This spatial approach, however, has raised questions about the etiology of obesity. It has been found that the correlation between healthy food access and healthy diets is not statistically consistent and is somewhat insignificant (2). In order to articulate the health effects of the community food environment, health geographers argue that other non-spatial variables need to be considered. One such variable is time.

Time shapes food access in two dimensions. On the one hand, the time component, or “temporality,” manifests in the urban food system (3) — grocery stores have different opening hours, farmers’ markets operate in different seasons. For example, it is found that grocery stores in downtown Columbus, Ohio, although there are many of them, close relatively early than stores located in the suburb. This disparity in space-time access to food is visualized by a 3D Geographical Information System (GIS) (4). The plentiful spatial access but limited temporal access could be explained by the store type (e.g., mostly privately owned) and the relatively high crime rate in the downtown neighborhood. Since downtown stores have limited operating hours, local residents may restrict their food choices and could be subject to diet-related health consequences. On the other hand, time shapes individuals’ mobility to procure food. People burdened with multiple social roles, such as childcare while raising an income, may find themselves less available to procure healthy food (5). A study using a travel diary survey identifies that the difference in time use exists between genders and among different races. Full-time employed women and African Americans are at the disadvantage of having less discretionary time (6). The lack of time may victimize these vulnerable social groups and expose them to food insecurity.

A 3D visualization of space-time food access in Columbus (4)


Thus, food access is not only a spatial issue but also a temporal issue. Employing a spatial approach alone to evaluate food access is insufficient. Other tiers of non-spatial variables, such as time, should be factored in to produce knowledge about food access equity and justify the health effects of community food environments.

Xiang Chen

Department of Geography

University of Connecticut

Xiang Chen is an Assistant Professor in the Department of Geography, University of Connecticut, USA. He received a Ph.D. in Geography at The Ohio State University (2014). His research is focused on GIScience, community health, and food accessibility.


  2. Caspi, C. E., Sorensen, G., Subramanian, S. V., & Kawachi, I. (2012). The local food environment and diet: A systematic review. Health & Place, 18(5), 1172-1187.
  3. Widener, M. J., & Shannon, J. (2014). When are food deserts? Integrating time into research on food accessibility. Health & Place, 30, 1-3.
  4. Chen, X., & Clark, J. (2016). Measuring space-time access to food retailers: a case of temporal access disparity in Franklin County, Ohio. The Professional Geographer, 68(2), 175-188.
  5. Rose, D., & Richards, R. (2004). Food store access and household fruit and vegetable use among participants in the US Food Stamp Program. Public Health Nutrition, 7(8), 1081-1088.
  6. Kwan, M. P. (2002). Feminist visualization: Re-envisioning GIS as a method in feminist geographic research. Annals of the Association of American Geographers, 92(4), 645-661.



The Environmental Protection Agency at Fifty: Promoting Deregulatory Science

photo of EPA headquarters

EPA Headquarters in Washington, DC. Photo Courtesy of Becky Mansfield

Established in the wake of the first Earth Day, the Environmental Protection Agency is also 50 this year. Today, the agency appears regularly in the news as a poster-child for President Trump’s regulatory rollbacks. I have researched the EPA for over a decade, including following the Trump EPA with fascination. What have I learned?

I have learned that when EPA takes its mission seriously, it makes progress protecting environmental and human health. Notable successes include reducing smog, acid rain, and lead exposure, and banning many dangerous pesticides [1].

Yet I have also learned that, not only are these issues ongoing, but EPA tends to downplay chemical harms, even in the wake of an avalanche of scientific findings and public awareness of the enormity of environmental change and long-term, cumulative health effects for humans and wildlife. EPA has always used a less-protective, risk-based approach that insists on certainty about harms before taking protective measures. Throughout its history, EPA has been influenced by corporate science-for-hire that highlights and even purposefully produces scientific uncertainty [2]. Also, EPA has not been good at addressing disproportionate harms. For example, my research showed that EPA’s approach to controlling exposure to the neurotoxin mercury was to tell pregnant women to eat less of certain kinds of fish; this makes women of color (who on average eat more fish) responsible for their own exposures while letting polluters (coal-fired power plants) off the hook [3]. A signature success of the Obama EPA was a rule finally requiring power plants to reduce their mercury emissions.

I have learned that the Trump EPA has assaulted protections from many angles [4]. For example, it found the Obama-era mercury controls to be inappropriate; repealed the Clean Power Plan; and decided against proposed bans of several deadly solvents.

Yet I have also learned that the Trump EPA does this not by disregarding science, but by producing deregulatory science. In particular, it has developed new approaches to scientific risk analysis that compel the agency to disregard many benefits of regulation, highlight its costs, dismiss many scientific studies as inadequate, and fail to evaluate many real-world exposures to chemicals (such as using them without protective gear). It justifies these moves using ideas of scientific transparency, reproducibility, and evidence-based decision-making.

A key lesson of fifty years of the Environmental Protection Agency is that when it comes to environmental protection, it is not enough to ask, “Is it science?” It is also crucial to investigate the values and interests that influence scientific judgment. Is evidence being produced and evaluated through the lens of protecting the fossil fuel and petrochemical industries and the interests of the powerful, or through the lens of being most protective to environmental and human health?


Becky Mansfield,

Professor of Geography,

Ohio State University



[2] On regulatory science at EPA, see e.g. Sheila Jasanoff,  The Fifth Branch (1990, Harvard University Press). On tactics of corporate science, see e.g. Kristin Shrader-Frechette, Taking Action, Saving Lives (2007, Oxford University Press).

[3] Becky Mansfield, Environmental health as biosecurity: “seafood choices,” risk, and the pregnant woman as threshold. Annals of the Association of American Geographers 102(5): 969-976. 2012.

[4] These findings are in an unpublished manuscript and were presented at the 2020 Dimensions of Political Ecology conference.