Mark Zondlo, an associate professor of civil and environmental engineering at Princeton University and its Andlinger Center for Energy and the Environment, develops tools to measure air pollution in more sophisticated and nimble ways than previously possible.His specially engineered laser sensors and drones help reveal the impact of greenhouse gases and air pollutants on the climate, where pollutants come from, and how clouds of air pollution — such as smog — form. The ultimate goal is to inform policy that will clear the air and our lungs and slash air pollution’s staggering impact on human mortality. Severe air pollution causes the premature death worldwide of more than 5.5 million people per year, according to news reports based on data compiled for the Global Burden of Disease project.