Christopher Lim is a Ph.D. candidate in Civil and Environmental Engineering at the Massachusetts Institute of Technology. He received his B.S. in Chemistry from the University of California, Berkeley and subsequently worked for Nanosys, Inc. on quantum dot lighting technology. Chris is currently working in Prof. Jesse Kroll’s research group, which studies air quality and the formation and evolution of atmospheric particulate matter (PM). Globally, poor air quality and the inhalation of fine particles are a leading cause of disease and premature mortality. They also have a strong effect on the Earth’s climate by modifying its radiative balance and by seeding clouds. Specifically, Chris’ research focuses on the chemical aging of particles in the atmosphere – an effect which is poorly constrained, but will change the physical and chemical properties of PM. A better understanding of how these particles behave in the environment will lead to more accurate chemical transport models and inform effective environmental policies that protect human health and the environment.