Groundbreaking nationwide study finds that people of color live in neighborhoods with more air pollution than whites

A press release from the University of Minnesota: A first-of-its-kind study by researchers at the University of Minnesota found that on average nationally, people of color are exposed to 38 percent higher levels of nitrogen dioxide (NO2) outdoor air pollution compared to white people.

Nitrogen dioxide comes from sources like vehicle exhaust and power plants. Breathing NO2 is linked to asthma symptoms and heart disease. The Environmental Protection Agency has listed it as one of the seven key air pollutants it monitors. The researchers studied NO2 levels in urban areas across the country and compared specific areas within the cities based on populations defined in the U.S. Census as “nonwhite” or “white.”

The health impacts from the difference in levels between whites and nonwhites found in the study are substantial. For example, researchers estimate that if nonwhites breathed the lower NO2 levels experienced by whites, it would prevent 7,000 deaths from heart disease alone among nonwhites each year.

The study entitled “National patterns in environmental injustice and inequality: Outdoor NO2 air pollution in the United States” was published in the April 15 issue of PLOS ONE, a leading peer-reviewed scientific journal.

“We were quite shocked to find such a large disparity between whites and nonwhites related to air pollution,” said Julian Marshall, a civil engineering associate professor in the University of Minnesota’s College of Science and Engineering and co-author of the study. “Our study provides a great baseline to track over time on important issues of environmental injustice and inequality in our country.”...

An aerial view of Harlem and the Harlem River, New York City, shot by Gryffindor, Wikimedia Commons,  under the Creative Commons Attribution-Share Alike 3.0 Unported license

Heat island risks and racial inequality

Inequality kills. From Bill M. Jesdale, Rachel Morello-Frosch, and Lara Cushing in Environmental Health Perspectives: In the United States, extreme heat events are responsible for about one in five natural hazard deaths (Borden and Cutter 2008). ... Furthermore, studies of extreme heat have shown large racial disparities in heat-related deaths (Greenberg et al. 1983; Jones et al. 1982; Kaiser et al. 2007; O’Neill et al. 2005; Schwartz 2005), although this is not universally the case (Ramlow and Kuller 1990; Weisskopf et al. 2002), and in at least one case, whites have been more affected than minority groups (Ellis et al. 1975). Land cover characteristics may contribute to these disparities (Uejio et al. 2011). Urban tree canopy is an important local mitigating factor for extreme heat (Hart and Sailor 2009; Oke et al. 1989), and impervious surfaces play a primary role in creating urban heat island effects (Oke 1982).

... Empirical evidence does not support the notion that cultural preferences explain observed disparities in tree cover (Martin et al. 2004; Zhang et al. 2007). Most existing research on racial disparities in tree canopy has been conducted within single metropolitan areas (Boone et al. 2010; Heynen et al. 2006; Landry and Chakraborty 2009; Lowry et al. 2012; Troy et al. 2007; Zhang et al. 2008). To our knowledge, no study has examined this issue nationally or assessed the role that residential segregation plays in driving distributions of urban tree coverage among racial/ethnic groups in the United States.

Impervious surfaces, such as asphalt and concrete, contribute to urban heat islands and surface temperatures via their high heat capacity, thermal conductivity, and often low reflectance of solar radiation (Asaeda et al. 1996; Stathopoulou et al. 2009). Relative to vegetation and soil, impervious surface also reduces evapo-transporative cooling. ... Several authors have also found that the extent of impervious surface is greater in neighborhoods with low socioeconomic status and a high proportion of minority residents, although these studies have been limited to a single U.S. city or state (Huang et al. 2011; Li and Weng 2007; Ogneva-Himmelberger et al. 2009).

...Ultimately we sought to elucidate how social inequalities shape disparities in heat risk–related land cover (HRRLC) characteristics. Toward this goal, we used racial residential segregation as a proxy for the degree to which a metropolitan area is characterized by historical and contemporary racial inequality and discrimination (e.g., Collins and Williams 1999). Political and socioeconomic forces have led to systemic racial and ethnic segregation, with important implications for community health (Morello-Frosch 2002; Morello-Frosch and Lopez 2006). Therefore, segregation is crucial to understanding social drivers of environmental health disparities (Gee and Payne-Sturges 2004; Morello-Frosch and Jesdale 2006) and, more directly, the potentially disproportionate health burdens of climate change on communities of color (Shonkoff et al. 2011)....

An aerial view of Philadelphia, shot by Payton Chung, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license