Dr. Zhang's research interests focus on energy and the environment. He studies the effects of airborne particulate matters (PM) and gaseous pollutants on air quality, climate change and ecosystem, using numerical models and experimental techniques. One particular area he is working on is environmental nanoparticles. Nanoparticle pollution affects public health by depositing deeper in our lungs and moving into the blood circulation. These nanoparticles can also grow into cloud condensation nuclei (CCN). Changes in CCN concentration may affect cloud reflectivity and lifetime, thus perturbing the energy balance of the planet. His research in this area focuses on characterizing various emission sources and their transformation in the atmosphere, especially the rapid changes in the first few minutes after emission. One important goal is to establish a source-to-receptor relationship for airborne nanoparticles. The "receptor" refers to either humans or the climate system. Dr. Zhang's group has developed CTAG (which stands for Comprehensive Turbulent Aerosol dynamics and Gas chemistry), an environmental turbulent reacting flow model, to simulate the transport and transformation of multiple pollutants in complex environments. In particular, he aims to develop a mechanistic understanding on 1) near-road air pollution and its potential mitigation strategies, 2) the effects of turbulent mixing on particulate emission measurements, and 3) the impacts of plume processing on regional air quality and climate simulations.

Another major area of Dr. Zhang's research interests is sustainable energy systems. In a low-carbon economy, the production of energy will be much less centralized and most energy services will be delivered to customers via the electric grid, and electric power systems, transportation systems and building systems are seamlessly integrated. However, the transition to such a low-carbon economy will face technological, institutional, financial and environmental challenges. Dr. Zhang is working with colleagues as an interdisciplinary team addressing those challenges. His research in this area focuses on aggregating a large number of distributed and controllable energy resources such as electric vehicles to provide a wide range of cost-effective systems services. These technologies will greatly facilitate the transition to a reliable, secure, efficient and clean power system.