Carbon dioxide emissions are up by almost 300 percent in the Phoenix metro area over the past three decades. It’s the result of population growth, says Mikhail Chester, a Fulton Schools associate professor of civil, environmental and sustainable engineering. In addition to the air pollution concerns raised by those increasing emissions, the city will be further challenged by the impacts of climate change, Chester says. The combination of smoggy brown haze over the city and the expected rise in heat in urban environments is certain to raise more public health issues for the Phoenix area.