Where Is the Los Angeles Heat Island Effect Most Intense?

"Heat islands are created by a combination of heat-absorptive surfaces (such as dark pavement and roofing), heat-generating activities (such as engines and generators), and the absence of vegetation (which provides evaporative cooling)," according to the Urban Heat Island Index for California from the California Environmental Protection Agency (CalEPA).

Using the new index which tracks temperatures across the state, CalEPA found that "[t]he highest temperatures crop up east of downtown Los Angeles and are pushed into the inland valley by ocean breezes," writes Sanden Totten, science reporter for KPCC. [Listen here]

"In that way we found that the urban heat island effect in the L.A. area really mimicked the ozone pollution problem in L.A. where it moved east and settles against the hills," said Gina Solomon, Deputy Secretary for Science and Health with CalEPA.

She adds that the index, a result of 2012 legislation (AB 296, Chapter 667, Statutes of 2012), is a way of "quantifying the urban heat island effect." It "is designed so that cities can have a quantifiable goal for heat reduction," according to the webpage.

"We call it not an urban heat island but an urban heat archipelago because it's like a whole chain of urban heat islands that run into each other," Solomon said.

“The Urban Heat Island Index offers state and local governments a tool to help prioritize areas for programs that reduce heat in urban communities, such as urban greening projects and cooler roofs and pavements," notes the press release.