Geographers looking at environmental inequality focus on how different segments of a population have unequal access to different levels of environmental quality, ranging in water, air, and soil resources.
Communities that live near industrial regions, for instance, tend to have greater likelihood than other communities in experiencing a variety of ailments affecting breathing, lung health, and asthma. A combination of long-term studies on the relationship between ethnic/racial groups and environmental inequality showed that in the United States there is a strong positive relationship between Latino and Black minorities living in areas with high NO2 and particulate matter pollution. In effect, industrial areas tend to be more focused in places where minorities may have lived. Overall, however, pollution exposure was found to be declining for racial/ethnic categories analyzed, even as generally exposure was greater for minorities. Even where sexual orientation was assessed, such as gay/transgender neighborhoods, evidence suggests environmental inequality or poor air quality is more likely.
Historical factors are often found to be important in shaping how some of these communities might find themselves living in environmentally deprived areas. Geographers use a range of quantitative analyses, that include spatial analysis, to qualitative assessment, such as employing causal process tracing, to understand historical reasons as to why environmental inequality develops. The implications of these studies are that for aid and assistance programs, environmental inequality needs to be a category of assessment when constructing policy. This includes issues such as housing provided, where often poor housing in countries, including in Belgium, were found to be associated with environmental degradation. The highlighted studies show that environmental inequality has become an important focus area for human geographers. However, much of the focus so far has been on urban regions rather than rural areas in the research literature.
 For an example of air pollution and health in relation to environmental inequality, see: Bickerstaff, K., & Walker, G. (2003). The place(s) of matter: matter out of place – public understandings of air pollution. Progress in Human Geography, 27(1), 45–67.
 For more on the study indicating where people live and exposure to air pollution, see: Kravitz-Wirtz, N., Crowder, K., Hajat, A., & Sass, V. (2016). The long-term dynamics of racial/ethnic inequality in neighborhood air pollution exposure, 1990-2009. Du Bois Review: Social Science Research on Race, 13(02), 237–259.
 For more on the relationship between sexual orientation and environmental quality, see: Collins, T. W., Grineski, S. E., & Morales, D. X. (2017). Sexual Orientation, Gender, and Environmental Injustice: Unequal Carcinogenic Air Pollution Risks in Greater Houston. Annals of the American Association of Geographers, 107(1), 72–92.
 For an example of how middle range theory is developed bridging qualitative and quantitative analyses, see: icotte, Diane. 2016. “The Importance of Historical Methods for Building Theories of Urban Environmental Inequality,” Environmental Sociology, 2, 3: 254-264.
 For more on an example of housing quality and environmental inequality, see: Lejeune, Z., Xhignesse, G., Kryvobokov, M., & Teller, J. (2016). Housing quality as environmental inequality: the case of Wallonia, Belgium. Journal of Housing and the Built Environment, 31(3), 495–512.