Numerous studies show that replacing darker roofs with highly reflective materials can reduce temperatures and cut energy costs.
It’s why utilities across the state offer incentives for installation. But a study by the South Coast Air Quality Management District suggests that cool roofs in Southern California can slightly increase ozone and smog.
“We just want to be very careful to not discourage the use of this technology because really a complete analysis of all of the benefits and potential negative air quality effects really needs to be considered before drawing any conclusions,” says Scott Epstein, an air quality specialist at the South Coast Air Quality Management District and the study’s lead author.Epstein says it’s worth studying to see if cool roofs in other parts of the state could increase ozone. He says the increase in air pollution could be avoided with more comprehensive standards for cool roofing materials. The study was published in the Proceedings of the National Academy of Sciences.