When Not Implemented Communally, Citizen Science Efforts May Reflect, Reinforce, and Potentially Exacerbate Environmental Injustice

Personal air sensors are increasingly being used to fill holes in governmental air-monitoring networks and provide users and their neighbors with accessible, accurate, and real-time information about air quality. These networks are needed given that governmental air monitors adequately cover only 19% of US counties.¹ But, as Sun et al. report in this issue (p.434), few studies have examined disparities in access to personal air sensors across space. This is critical because sensor access provides households with important health-protective information.

Looking across the state of California, Sun et al. found that lower socioeconomic status, higher concentrations of fine inhalable particles with diameters 2.5 micrometers and smaller (PM_2.5), and greater racial/ethnic minority composition were associated with fewer PurpleAir sensors per census tract in California. For example, poverty rates were double in tracts without any sensors, relative to those with three or more. This study, along with several others,^2,3 is among the first to quantify sociospatial disparities in access to personal air sensors. Importantly, Sun et al. teased out the spatial dynamics of nonoperational sensors, which are more common in socially disadvantaged tracts, and analyzed uneven growth in the PurpleAir sensor network through time. Over the four years under study, they found that California saw a 20-fold increase in the number of sensors, yet socially disadvantaged tracts had a lower rate of increase than more advantaged tracts. As PM_2.5 is disproportionately concentrated in low-income, minority neighborhoods in California,⁴ Sun et al. and the other studies^2,3 show the double burden experienced by residents as they also have reduced access to relevant air pollution exposure information.

LIMITS TO MARKET-BASED CITIZEN SCIENCE

The social disparities in PurpleAir sensor locations documented in California may reflect broader limitations of market-based citizen science technologies for increasing the availability of air pollution information in an equitable manner. When not implemented communally, these citizen science efforts may reflect, reinforce, and potentially exacerbate environmental injustices. As Sun et al. found, Whiter and wealthier California communities had more sensors soon after PurpleAir started up, and then the gap in sensor access grew over time between disadvantaged and nondisadvantaged communities. These gaps converge with disparities in other air pollution protective behaviors, such as wearing air pollution masks and installing in-home air-filtration systems.⁵ The emergence of market-based approaches to monitoring air quality have shifted responsibility onto the individual consumer, and these approaches privilege those with enough affluence to buy sensors for their homes.

There are exceptions to this trend, as environmental justice communities (i.e., low income, minority communities beset by environmental challenges) have gained access to sensors and used them to monitor air quality in their communities. This is happening in the Glades region of Florida where journalists installed PurpleAir sensors so residents could track air pollution from sugar cane field burning. Residents used this information to build a legal case against the farmers for negligence in burning cane, which is now in federal court.⁶ Existing research on social disparities in access to sensors, coupled with cases of “fence-line” environmental justice communities using sensors to aid their cause, highlights how citizen science may both neglect and empower disadvantaged communities.

DEMOCRATIZING CITIZEN SCIENCE

We believe there is a role for universities, public health departments, environmental agencies, and nongovernmental organizations to democratize access to sensors by coordinating efforts to distribute sensors in socially disadvantaged communities that lack them. There are examples of this happening that can serve as models for other communities. At the University of Utah, the AirU team brings sensors and an air quality curriculum to Salt Lake County middle and high schools.⁷ In an effort led by Mullen, we are currently working to install PurpleAir sensors in Salt Lake County environmental justice neighborhoods that are underserved by sensors. Collaborations between the City of Tacoma (Washington), Portland State University, and University of Washington have installed sensors in Tacoma and created a structure to ensure that they stay operational.⁸ Air quality agencies have also taken the lead in distributing sensors. The South Coast Air Quality District (SCAQD) in California distributed 400 sensors in environmental justice communities (Sun et al.). Puget Sound Clean Air Agency loans sensors temporarily to residents, educators, and community groups.⁹ Nongovernmental organizations are also active in increasing sensor access in communities with high need. In California, the Asian Pacific Islander Forward Movement distributed 50 sensors in northeast Los Angeles County with financial backing from the SCAQD.³ Citizens for Clean Air installed 24 sensors near Grand Junction, Colorado, to supplement the two state-run monitors to better understand how wildfire, truck traffic, and natural gas extraction are influencing local air quality.⁷

We recommend that these community leaders consider prioritizing locating sensors in community institutions, like schools, libraries, health care settings, and community centers, instead of at private homes (or in addition to private homes), for two reasons. First, these kinds of partnerships with community institutions can facilitate sensor access across a wide range of sociospatial contexts (e.g., at all schools in a district), as opposed to disproportionately at homes in affluent and White neighborhoods. Second, as Sun et al. report, it may decrease the numbers of sensors that become nonoperational over time as these institutions have reliable Internet access and electricity and are less likely to move than are private citizens. There are challenges to this approach, such as the need to install outdoor electrical outlets and troubleshoot public WiFi settings, which can be overcome with adequate lead time and committed people.

CITIZEN SCIENCE AND SOCIAL CHANGE

There are several different ways in which sensors can be used to achieve social change, some of which align more closely with the democratic ideals of citizen science than others. When approached with environmental justice as the goal, sensors are distributed in areas with the greatest need, which we argue should be characterized on the basis of high levels of PM_2.5, reduced access to sensors, and social disadvantage. Although environmental justice concerns may guide sensor placement in particular fence-line communities (e.g., Florida Glades⁶), such concerns are not the driving force. Instead, sensors tend to be purchased by individuals residing in relatively affluent neighborhoods (Sun et al. and other studies^2,3). When already privileged people have prime access to sensors, a real concern is that they may harness that information to fight local sources of pollution based on a NIMBY or not-in-my-backyard mentality. NIMBYism has the potential to intensify patterns of environmental injustice by shifting sources of pollution to already burdened communities with reduced access to information.¹⁰ Finally, there are applications that fully build on the democratic ideal of citizen science by using the public production of PM_2.5 data as a catalyst for policy change.

In an ideal world, the information produced by an equitably distributed citizen science sensor network could be harnessed to better protect everyone’s health—for example, by leveraging changes in US federal PM_2.5 standards, which are sorely needed. A panel of esteemed scientists “unequivocally and unanimously concluded that the current PM_2.5 standards do not adequately protect public health.”^11(p681) In September 2021, the World Health Organization boldly cut its recommend annual average PM_2.5 standard in half. Better monitoring and more PM_2.5 data points, produced by engaged citizen scientists, could be instrumental in catalyzing bottom-up demands for US policy changes in PM_2.5 standards.