Scientists identify the chemical culprits responsible for smog trapping the sun's warmth

Hanging over the world's major cities, a brown haze of smog traps the warmth from sun. Acting like a warming blanket, this haze has a substantial impact on the climate. However, the chemical complexity of the haze makes it hard to separate out the compounds that absorb the sunlight from the stew of other chemicals. Scientists at Pacific Northwest National Laboratory and the University of California, Irvine identified the culprits—a set of molecules called brown carbon chromophores.