Environmental Injustice and Racial/Ethnic Heterogeneity in Houston, Texas

Michel G Loustaunau Garcia, University of Texas at El Paso


This thesis seeks to contribute to distributive environmental justice (EJ) research by analyzing racial/ethnic and intra-ethnic disparities in potential health risks from exposure to hazardous air pollutants (HAPs) in Harris County, the most populous county in Texas. Previous EJ research in this urban area has not examined intra-ethnic heterogeneity in exposure to air pollutants or attempted to compare social disparities in exposure to air pollution caused by vehicular (mobile) and point (stationary) sources. The goal of this study is to determine how the EJ implications of cancer risks from inhalation exposure to HAPs from mobile and stationary sources differ across and within each major racial/ethnic group (i.e., Hispanics, non-Hispanic Blacks, and non-Hispanic Whites) by disaggregating each group based on contextually relevant social characteristics. This study integrates census tract level cancer risk estimates associated with on road mobile and stationary point HAP sources from the Environmental Protection Agency’s National-Scale Air Toxics Assessment (2011) with socio-demographic data from the American Community Survey (2009-2013). Statistical analyses are based on bivariate correlations and multivariate generalized estimating equations (GEEs) which account for clustering of tracts within the study area. The first phase of the study follows a conventional approach based on previous EJ studies where each racial/ethnic category is treated as a single group. The results indicate that both Hispanics and non-Hispanic Blacks are exposed to significantly higher cancer risk from vehicular HAP emissions than non-Hispanic Whites, but similar racial/ethnic disparities are not observed for stationary point sources. In the second phase of the study, three different sets of models are used to separately disaggregate each major racial/ethnic group (i.e., Hispanics, non-Hispanic Whites, and non-Hispanic Blacks) based on six characteristics: poverty, nativity, homeownership, educational attainment, English language proficiency, and age. For on road mobile sources of HAPs, results indicate that those who are in poverty, foreign born, renters, and with limited English proficiency are disproportionately located in neighborhoods exposed to significantly higher cancer risk, regardless of their major racial/ethnic designation. For stationary point sources, the only socially disadvantaged subgroups facing significantly higher cancer risk include non-Hispanic Whites who are renters and less educated as well as Hispanics without a high school diploma. These differences in EJ results can be explained, in part, by the spatial distribution patterns of these two HAP emission sources in this county. This thesis contributes to EJ research by demonstrating the need to consider racial/ethnic heterogeneity and conduct intra-categorical analysis for uncovering social inequalities that are likely to be concealed when broadly defined racial/ethnic categories are used.

Subject Area

Environmental Justice|Ethnic studies

Recommended Citation

Loustaunau Garcia, Michel G, "Environmental Injustice and Racial/Ethnic Heterogeneity in Houston, Texas" (2018). ETD Collection for University of Texas, El Paso. AAI13424200.