Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.


Systemic environmental racism exposed

A short window of opportunity during the COVID-19 economic shutdown provides striking evidence of environmental disparity.

At a time when environmental justice advances as a field, precisely assessing the disproportionate impact of pollutant emissions on communities of colour has proven difficult because exposure to pollution is strongly correlated with socioeconomic variables. Communities of colour is a commonly used term in the United States to describe Black, Latinx, Asian and Indigenous communities. Under normal conditions, the long history of institutional racism couched in legal discrimination limiting access to housing, and an overrepresentation of polluting enterprises operating in or near communities of colour cannot be disentangled from the polluting impact of the local economy. The coronavirus disease 2019 (COVID-19) pandemic opened a unique and valuable research opportunity to study what happens in terms of pollution exposure when turning the state economy ‘off’. Writing in Nature Sustainability, Richard Bluhm and colleagues1 report how they innovatively took advantage of the strict COVID-19 economic shutdown in California to separate the confounding effects of socioeconomic factors from pollution. Their analysis shows that the everyday functioning of the economy as a whole, not just local conditions, contributes to the disproportionate impact of pollution on communities of colour in California.

Credit: Cultura Creative RF / Alamy Stock Photo

Environmental justice research typically consists of spatial analyses largely focused on specific emission sources2. Quantitative environmental justice studies are predominantly measures of the impact of a local polluter on an adjacent neighbourhood or census tract3. Census tracts are statistical subdivisions of a county for the purpose of demographic comparison. A census tract has a population between 1,800 and 8,000, with an average population of 4,000 people. Environmental activism is primarily focused on protesting the construction of highly polluting industries in local communities4. The groundbreaking work of Pastor et al5. in 2005 pushed quantitative research to develop a broader type of geographic analysis including mobile sources rather than keeping a focus on proximity. Bluhm and colleagues were privy to the unique circumstances of the COVID-19 economic shutdown, which allowed them to expand the reach of previous studies, to analyse the impact of pollution in the entire state of California.

Bluhm and colleagues used the strict COVID-19-related economic shutdown in California as a period of ‘intervention’ to analyse the impact of the drastic reduction of emissions on communities of colour. They measured pre- and post-shutdown air quality (January to April 2019 and 2020) as a way to evaluate systemic racism and environmental injustice in California. They found that levels of particulate matter with a diameter of less than 2.5 μm (PM2.5) and nitrogen dioxide (NO2) emissions produced primarily by transportation and agricultural activity declined at a larger rate in Latinx and Asian communities than in wealthy white communities. Remarkably, this was true even though residents of low income, primarily Latinx communities, drove more than those in wealthy neighbourhoods during the shutdown, as many of them were probably frontline workers, and therefore were responsible for higher levels of transport emissions. In addition, they found that although Latinx communities have lower income levels than Asian communities, both Latinx and Asian communities had similar levels of reduction, which lends more weight to their conclusion that systemic racism is a major factor. They did not observe a similar reduction rate of pollution in Black communities. This could be due to the smaller and less concentrated Black population in California, of 7% versus 39% Latinx and 16% Asian, and could also demonstrate that factors other than the in-person economy, such as current and historical bias in policy, may be primarily responsible for the pollution burden for Black communities in the state. The authors conclude that the air pollution reduction for Latinx and Asian communities was not caused by the impact of local factors. The functioning of the whole of California’s economy has a disproportionate polluting impact on these communities, despite local conditions.

The data used in the analysis were collected from California Air Resources Board (CARB) air monitors, a network of monitors introduced by the State of California, combined with Purple Air Monitors, which are installed voluntarily by resident citizen scientists. In addition, satellite data were collected to measure NO2 levels. This unique combination of data helped to account for the likely bias owing to the location of the air monitors. While accounting for shortcomings, the study raises awareness about the need for greater care and mindfulness of monitor placement to produce more accurate data of air quality in underserved communities.

The work by Bluhm and co-authors will stimulate new approaches to studying air pollution that allow us to understand why and how regional activity has a disproportionate impact on communities of colour. Although attention tends to focus on local environmental hazards, this research demonstrates that the whole economic system can have a substantial disproportionate impact on communities of colour. It reinforces the need for a holistic approach to economic planning that takes into consideration the fact that disproportionate pollution generation is not just a local issue. It calls for a reassessment of risk, cost and distributive impacts within current regulatory practices.

The US Environmental Protection Agency is currently discussing the changes needed to better address environmental justice — including proposed measures and strategies that eliminate race in the way vulnerable communities are identified6. Against this backdrop, the work by Bluhm and colleagues is particularly important, as it provides a causal link between systemic racism and pollution. The study clearly shows that if policymakers shy away from using race as a factor and instead only use income, unemployment rate and proximity to environmental hazards as variables to identify vulnerable communities they will fail to effectively identify communities in need and take the appropriate measures to equalize pollution impact. Bluhm and colleagues demonstrate that income disparity remains an important indicator of environmental risk, yet race and ethnicity are stronger determinants. These are striking findings that could only be produced under the unique circumstances of the shutdown. The study asserts the importance of re-envisioning a state economy that at its core is intentional about the broad, yet equitable reduction of pollutants, in addition to focusing on targeted local environmental justice interventions. Importantly, the authors propose a useful equation based on their findings that could effectively be employed by policymakers to balance the impact of pollutants, so that a broad reduction of pollution does not retain disparities. Their model could enhance current cost–benefit analysis by providing a more robust analysis of the disparate impact of environmental hazards, while recognizing the important role of race and ethnicity. Specifically for California, their proposed model could be added as a mechanism to enhance the work of the California Bureau of Environmental Justice so they can have an additional tool to create a more precise approach to understanding the share of environmental hazards in communities.


  1. Bluhm, R. et al. Nat. Sustain. (2022).

    Article  Google Scholar 

  2. Mennis, J. & Heckert, M. in The Routledge Handbook of Environmental Justice (eds Holifield, R. et al.) 207–221 (Routledge, Taylor & Francis Group, 2018).

  3. Chakraborty, J. in The Routledge Handbook of Environmental Justice (eds Holifield, R. et al.) 175–189 (Routledge, Taylor & Francis Group, 2018).

  4. Pellow, D. N. Am. Behav. Sci. 43, 581–601 (2000).

    Google Scholar 

  5. Pastor, M. Jr, Morello-Frosch, R. & Sadd, J. L. J. Urban Aff. 27, 127–148 (2005).

    Article  Google Scholar 

  6. Friedman, L. White House takes aim at environmental racism, but won’t mention race. The New York Times (February 2022);

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Dena Montague.

Ethics declarations

Competing interests

The author declares no competing interests

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Montague, D. Systemic environmental racism exposed. Nat Sustain 5, 462–463 (2022).

Download citation

  • Published:

  • Issue Date:

  • DOI:


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing