Atmospheric aerosols—tiny particles suspended in the air—can have significant effects on our environment, including reduced visibility and deposition of acids, toxic chemicals and nutrients to ecosystems and crops. These effects can have severe short- and long-term negative impacts on the environment and human health. The magnitude of these effects, however, has been hard to understand, owing to the difficulty of measuring them. To address this problem, a research team led by Professor Jimenez develops and deploys advanced instrumentation for real-time measurement of the size, chemical composition and morphology of aerosols in the atmosphere. Through largescale, global field studies and in-house programming, Jimenez and his team have been able to obtain real-time quantitative data that enable much faster progress toward understanding atmospheric processes. Jimenez has been the fifth most cited scientist worldwide in geosciences over the last 10 years and was among the 2014 Highly Cited Researchers (Thomson Reuters) in both geosciences and engineering. In 2012 he received an AGU Ascent Award “as an exceptional mid-career scientist demonstrating excellence in research and leadership in his field.” Jimenez joined the faculty at CU-Boulder in 2002.