Disparities in Distribution of Particulate Matter Emission Sources by Race and Poverty Status

Authors: Ihab Mikati, BS, Adam F. Benson, MSPH, Thomas J. Luben, PhD, MSPH, Jason D.Sacks, MPH, and Jennifer Richmond-Bryant, PhD



Particulate matter (PM) is a type of air pollution. It is a mixture of airborne solids such as particles of dust, soot, and other matter, and liquid droplets. While the particles can be a wide range of sizes, those less than 10 microns in diameter (noted as PM10), and especially the fine particles (PM2.5), are more likely to get into our lungs and to cause and exacerbate serious health problems.

Children are especially vulnerable. Asthma, a condition affecting 8.4% of American children, is exacerbated by PM exposure (1). In 2013, asthma was the primary cause of 1.6 million emergency room visits for children, and in 2015 over 200 children died because of their asthma (1).

Black children and children living below the poverty line experience even higher rates of asthma (13.4% and 11.1%, respectively). In addition, black children are 4 times more likely to be admitted to the hospital for asthma, and have a death rate 10 times that of non-Hispanic white children (2). Previous research has shown that stationary sources of air pollution are found in higher concentrations near socially disadvantaged populations - specifically low income communities and communities of color. Race and poverty are intertwined in America, with 34% of Black children living in poverty compared to 19% of children overall (2,3). A deeper examination of disproportionate pollutant exposures across racial versus socioeconomic lines can better inform policies to address health disparities.


To quantify nationwide disparities in the location of particulate matter (PM)-emitting facilities by the characteristics of the surrounding residential population and to illustrate various spatial scales at which to consider such disparities.


The study used data from the Census Bureau’s American Community Survey along with other census data to divide the United States into block groups, then assigned PM-emitting facilities, as identified by the 2011 National Emissions Inventory, to those blocks. The burden associated with the facilities was calculated for different racial/ethnic groups and by poverty status. In addition to the presence or absence of a facility, the magnitude of emissions was considered when determining burden. National, state and county data were quantified for comparison of disparity.


Non-White populations overall experienced 1.28 times the burden of the general population, and Black populations, specifically, experienced the greatest degree of disparity in the siting of PM emitting facilities at national, state, and county levels, burdened with 1.54 times the PM emissions faced by the general population. Populations living in poverty experienced 1.35 times the burden of the general population.


Disparities in pollution exposure from PM emissions were more pronounced for Black populations (regardless of wealth) than for those living in poverty. Thus, it is insufficient to consider only socioeconomic status when working to decrease burdens caused by PM. Emission disparities resulting from structural racism exist on a national level and at the state and county levels in most instances.


The U.S. Environmental Protection Agency’s (EPA) National Ambient Air Quality Standards (NAAQS), established under the Clean Air Act, set limits on particle pollution for both PM2.5 and PM10, in addition to several other “criteria” air pollutants. However, while major improvements in air quality have occurred under the Clean Air Act overall, disparities persist at regional and local levels. Approximately two in five people in America live in a place where the air is unhealthy to breathe, including children, who breathe more air per pound of body weight than adults (4).

Previous studies found disproportionate exposures to other air pollutants along racial lines (5,6). Regulations targeting emissions need to take the racial/ethnic makeup of an area into special consideration (not just the area’s poverty levels) to ensure communities do not continue to experience a disproportionate burden to air pollution. Moreover, there needs to be sufficient funding for adequate monitoring and enforcement of air quality standards.

The findings of this study also indicate the need for further and specific protections for communities of color, not just around PM or air pollution exposures. Another recent example of disproportionate exposure burdens is the 2014 mass lead contamination of drinking water in Flint, Michigan, where many homes still do not have safe drinking water from their taps. EPA’s investigation into the circumstances surrounding the poisoning uncovered racially discriminatory permitting practices for the Genessee Power Station (7).

The EPA’s Environmental Justice 2020 Action Agenda, which is the agency’s strategic plan for environmental justice 2016-2020, defines environmental justice as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin or income with respect to the development, implementation, and enforcement of environmental laws, regulations and policies” (8). Under this Agenda, the EPA awards grants to help communities address environmental health disparities. Until policies and regulations achieve environmental health equity, this Agenda needs continued support in order to help disadvantaged communities lacking the resources and political capital to protect themselves from environmental harm.

It is imperative that state and local governments commit to removing barriers to inclusive participation of impacted communities in siting and permitting decisions. Affected communities need to be invited to the table through multiple modes of clear communication, and unreasonable rules should be removed. For example, in some places, such as Illinois, a citizen may only appeal a decision if he/she attended the public hearing prior to a site’s approval. Thus, barriers to disadvantaged communities commenting in the proposal stage carry through to the appeal stage
(9). Structural racism needs to be addressed across the board at all levels of government and in other institutions and organizations, in order to truly get to the root of health disparities arising from and perpetuated by environmental injustices.

For more information on children and health disparities, view our policy factsheet HERE.


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  1. US Environmental Protection Agency. 01R-94-R5 MDEQ closure letter. 2017. Available at: https://www.epa.gov/ocr/01r-94-r5-mdeq-closure-letter. Accessed March 24, 2017
  1. EPA. (2016, October). EJ 2020 Action Agenda. Retrieved March 1, 2018, from https://www.epa.gov/sites/production/files/201605/documents/052216_ej_2020_strategic_plan_final_0.pdf
  2. Illinois Environmental Protection Agency. (2003, March). Siting a Pollution Control Facility in Illinois. Retrieved March 30, 2018, from http://www.epa.state.il.us/community-relations/pollution-control-facilitysiting.pdf

Article found in Environmental Health Perspectives.