Changes in Exposure to Industrial Air Pollution Across the United States from 1995 to 2004: The Role of Race, Income and Segregation
Author: Ard, Kery J, ard.7@osu.edu
Department: School of Environment and Natural Resources
University: University of Michigan, USA
Supervisor: Dorceta Taylor
Year of completion: 2014
Language of dissertation: English
Keywords:
Environmental Justic
, Air Pollution
, Geography
, Segregation
Areas of Research:
Environment and Society
, Stratification
, Health
Abstract
A core research concern in the field of environmental justice is to understand how exposure to industrial toxins varies by race/ethnic and class. However, as the field has evolved there have been dramatic declines in air pollution, the toxicity levels of these pollutants, and shifts in the residential settlement patterns of racial and economic groups in the United States. Current work in this field has rarely taken these trends over time into account. Because environmental justice theories in this area are based on the manufacturing industry and how it puts some populations at risk more than others, to understand how toxic emissions from these industries are changing over time is important for evaluating the continued usefulness of current theory. This dissertation addresses these limitations by examining the annual exposure for the years 1995 to 2004 of non-Hispanic whites (herein referred to as whites), African-Americans and Hispanics across the United States to 572 industrial chemicals weighted by their toxicity to human health.
The first essay provides a foundational understanding for how pollution exposure has changed for different racial/ethnic and socio-economic groups across the U.S. from 1995 to 2004. Results indicate that pollution exposure is declining over time for every socio-demographic group. However, there remains a gap between African-Americans and whites, with African-Americans having greater pollution exposure than whites, and Hispanics having similar exposures to that of whites. Within race/ethnic groups, households with higher income have greater protection from toxic substances. However, between races, African-Americans with a higher income and education still have greater exposure than whites and Hispanics with lower incomes.
The second essay assesses the links between racial residential segregation and pollution exposure, and how this association is changing over time. I use relative centralization, an alternative measure of segregation than has the one most frequently used and one that more precisely captures the clustering of African-Americans around the central city, a spatial pattern that is argued to be at the base of unequal exposure to industrial toxins by race/ethnic in the U.S. Results show that racial segregation of metropolitan areas is significantly related to pollution exposure of block groups in these areas; however this association is decreasing over time. This paper also tests hypotheses from the literature about the dynamics of industrial pollution exposure in central cities and outside these areas. I show that counter to what has been previously theorized, central city locations have higher pollution exposure than areas central cities, and block groups with larger proportions of African-Americans outside cities experience greater industrial toxin exposure than areas with larger proportions of whites.
The third essay examines how the concentration of poverty in a metropolitan area is related to the toxic pollution exposure of block groups located within it. Findings demonstrate that those metro areas with greater poverty segregation have on average higher rates of toxic pollution exposure. In addition, those block groups with greater proportions of impoverished residents are more likely to have greater exposure to industrial toxins in metro areas with higher levels of poverty segregation.
