Environmental justice: A Phoenix study

It's hot in Phoenix. But did you know it is hotter in poorer parts of town? Last fall, The Arizona Republic reported on a study by ASU researchers Darren Ruddell and Sharon Harlan that concluded the more affluent areas of the city were actually cooler than parts of the city where residents had lower incomes. In their research, Ruddell and Harlan found that for every $10,000 increase in the income of an area, the temperature of the area drops by one-half degree Fahrenheit. How is this possible?

"Heat discriminates," according to the report. More specifically, the environment of the poor and affluent areas is different enough to cause the disparity. Richer areas have more grass and trees to shade and provide cooling, while poorer areas lack vegetation and are closer to freeways, subjecting the poor, elderly, and children to higher temperatures. "The people who are most vulnerable are also living in the worst conditions. It's a double whammy," Ruddell told the newspaper.

The urban heat island effect is more severe in poor, urban areas, and abates as it moves out to wealthier suburbs. The study was done in 2005, which from personal experience was an incredibly hot summer. The study found that urban neighborhoods were exposed to 22 hours a day of intense heat, whereas residents in highly-landscaped neighborhoods were exposed to just 4 hours of extreme heat. It was the landscaping -- not the location --that caused neighborhoods to be hotter. There was evidence of great temperature variance in neighborhoods separated by only a few blocks.

The situation in the Phoenix metro area is similar to Konisky's (2009) discovery of environmental injustice in government enforcement of environmental laws and codes. He discovered that there was a significant difference in enforcement between richer and poorer counties across the United States for the Clean Air, Clean Water, and Resource Conservation and Recovery acts. For these three laws, Konisky discovered "the effects of poverty on state enforcement are sizeable" (ibid. 114). Consider these findings:

* For every percentage increase in a county's poverty, enforcement of the Clean Air Act dropped 2.3 percent;
* For every $1,000 decrease in median household income, there is a corresponding decrease of 3.3 percent in enforcement of the Clean Air Act; and
* For every percentage increase in a county's poverty, enforcement of the RCRA decreased by more than 5 percent.

Also similar are issues with smart growth, which is supposedly meant to revitalize the core of cities, but too often new urbanism becomes "new suburbanism" (Rast, 2006, 252). In Phoenix, the core, with its poorer residents, is overwhelmingly affected by high temperatures because of the heat island effect, and there is less consideration of cooling properties of landscaping. Also, proximity to heat-attracting freeways and emissions from vehicles clearly place an undue burden on the city's poor. Often, smart-growth initiatives "take place without a strong commitment to improving conditions for low-income, inner-city residents" (ibid. 253). Interestingly, the ASU study also found that middle-class neighborhoods on the fringes were affected by long exposure to high temperatures because of a lack of mature landscaping.

Harlan and Ruddell's study is an unambiguous example of an environmental-justice issue because of the pronounced temperature variation in areas based on income. The Republic article reports that the city is already taking steps to help low-income families weatherize homes. However, as high temperatures rise, more will need to be done. Any plans to revitalize parts of the metro area need to take into consideration how the development will increase or decrease the amount of time residents are exposed to intense heat.