Nearly two decades ago, Chicago was struck by a fatal heat wave that resulted in 465 certified heat-related deaths. New York University sociologist and author of "Heat Wave: A Social Autopsy of Disaster in Chicago," Eric Klinenberg, determined that one aggravating factor of the death toll was the high concentration of buildings and pavement mostly in urban areas.
Klinenberg also reported a 1.5 to 1 African American to white mortality ratio.
Fast-forward to 2013. University of California, Berkeley researchers found a similar pattern in that racial minorities are more susceptible to heat risk than their white counterparts.
"If you're in an area with no trees and a lot of pavement, there will be more heat absorbed compared to other parts of the city. The people that live in those neighborhoods tend to be minorities," said epidemiologist Bill M. Jesdale, a study author.
According to the national study, heat risk conditions are defined as areas where at least half of the population lacks shade from trees and at least half of the ground is covered by "impervious surfaces" including roofs, driveways and sidewalks.
The study examined 63,436 census block groups and 304 metropolitan areas across the country using satellite imagery to determine the amount of area covered by trees and hard surfaces.
Of the communities examined, 52 percent of blacks were considered more likely to live in heat risk-related land cover conditions, while non-Hispanic Asians were 32 percent more likely and Hispanics were 21 percent more likely to live in such areas.
"Racial minorities tend to live in more densely populated neighborhoods and more people in buildings mean more pavement and less trees," said Jesdale.
Similarly, during the Chicago heat wave of 1995, the high temperatures were exacerbated in urban communities particularly during evenings due to the concentration of pavement. These areas release heat that has been absorbed during the day into their immediate surroundings.
The study also explains that the racial makeup of a neighborhood affects the tree-to-pavement ratio - even in areas that share the same population density.
"If you compare a dense metropolitan area that is predominately white with one that is minority, there is likely to be more trees in the white neighborhood," said Jesdale.
By comparison, Tim Jeffries, director of planning and policy at Friends of the Parks in Chicago, provided an alternative opinion. "The biggest indicator is not necessarily a lack of trees or parkways, but an influx of vacant lots in urban communities. If you have a well-maintained street, the likelihood that the residents will maintain the streets by themselves is higher," he said.
"The park district did a pretty good job of distributing the tree canopy."