African-Americans, particularly in the Midwest, are far more likely to live within a mile of a polluting industrial facility than white Americans, according to a national study by University of Michigan researchers.

While evidence linking race and pollution exposure is well known, the new study is the first known national effort to use survey data, which is more detailed than more commonly used census data. The responses of more than 3,600 Americans to questions about their lifestyles, race and income were integrated with pinpoint locations of more than 21,000 industrial sites. Knowing the precise location of survey respondents and these industrial sites allowed the U-M researchers to conduct more detailed analysis and reach more detailed conclusions.

The study found 58 percent of African-Americans in Midwest metropolitan areas lived within a mile of a polluting industrial facility compared to only 35 percent of white Americans. Similar disparities were found between the races in the U.S. South and West, but not Northeast.

The researchers present these and other findings in an academic paper appearing in the November supplement to the American Journal of Public Health.

"Blacks and [other] respondents at lower educational levels and, to a lesser degree, lower income levels were significantly more likely to live within a mile of a polluting facility," said Paul Mohai, a professor in the U-M School of Natural Resources and Environment, and the paper's lead author. The disparities between African-Americans and white Americans persisted even after adjusting for socioeconomic and other demographic characteristics, the authors state. This disparity suggests that factors uniquely associated with race, such as housing segregation and the targeting of African-American communities to place businesses more likely to pollute, may be involved, they said.

Professor Mohai's U-M co-authors are: Paula M. Lantz, Department of Health Management and Policy, School of Public Health; Jeffrey Morenoff and James S. House, both of the Department of Sociology, College of Literature, Science, and the Arts; and Richard P. Mero. All are also affiliated with the U-M Institute for Social Research. The research was supported by the National Institute on Aging.

"The primary contribution of this work is methodological, given that ours is the first national study to our knowledge to demonstrate the potential of combining location and sociodemographic information from surveys with administrative data on environmental hazards while also providing new evidence pertaining to historical racial and socioeconomic disparities in the distribution of environmental hazards," the authors state.

Census data is presented by geographic units, such as counties, census tracts and zip code areas, Professor Mohai said. However, the precise distance of people within those geographic units to hazardous sites is difficult to determine. Researchers have had to develop estimation procedures to determine how much of the population within sections of the census' geographic units to count as within a specified distance.

Survey data have no such limitations because people can be represented graphically and statistically as geographic points; as a result, their distances to hazardous sites can be measured precisely. Racial, socioeconomic and other background characteristics can also be correlated precisely with distances to the sites. Only a few localized studies have used survey data in this way to assess environmental inequalities, and those studies generally confirm the presence of social disparities in proximity to environmental hazards, Professor Mohai said.

Another advantage of using survey over census data involves the greater range of background information collected from people. Surveys can be used to ask about health status, access to health care and lifestyles, information not included in the census.

The answers to such questions can then be used to further examine links between living near hazardous sites and health, or whether disparities in pollution burdens are more (or less) strongly linked to health status than are disparities in lifestyles and access to health care.

The data for the U-M analysis come from the American's Changing Lives Study (ACL), a national probability sample of 3,617 adults, and from U.S. Environmental Protection Agency's Toxic Release Inventory (TRI). The TRI is a national database of 21,894 industrial facilities reporting on- and off-site disposal of almost 650 toxic chemicals.

The ACL's baseline survey year of 1986 was chosen to establish a foundation upon which to measure future changes. Although ACL respondents were re-interviewed in 1989, 1994 and 2001, the authors focused on the 1986 sample because it was representative of the U.S. adult population when the study was initiated. The TRI data (1987) closest to the ACL baseline year was used. Data from the 2001 sample was used to replicate the analyses and the results were similar, the authors state.

About the American Journal of Public Health
The American Journal of Public Health is the monthly journal of the American Public Health Association (APHA), the oldest organization of public health professionals in the world. APHA is a leading publisher of books and periodicals promoting sound scientific standards, action programs and public policy to enhance health. More information is available at www.apha.org.

About the School of Natural Resources and Environment
The School of Natural Resources and Environment's overarching objective is to contribute to the protection of the Earth's resources and the achievement of a sustainable society. Through research, teaching and outreach, faculty, staff and students are devoted to generating knowledge and developing policies, techniques and skills to help practitioners manage and conserve natural and environmental resources to meet the full range of human needs on a sustainable basis.
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