My general research focus is on the influence of air pollution on both climate and human health. My specific interest is particulate matter (PM), and I have done a wide range of studies on the emission, formation, deposition and impacts of PM. I am particularly interested in how PM impacts climate by modifying the radiation balance of the atmosphere and I have done studies in both pristine regions of the world (Greenland and the Himalaya), as well as hazy regions (the Southeastern US, China, and India). More recently I have been studying the influence of PM on human health with emphasis on determining the relative contributions of sources (such as biomass burning and vehicular emissions) to acute health impacts. I am also involved in developing and deploying the next generation of air quality sensors to inform citizens on the quality of the air they are breathing so that they can make informed decisions to improve their air. My vision involves combining a multidisciplinary, multicultural approach to research and education that brings together researchers from around the world to collectively work together to make the air cleaner.