Environmental aerosols and nanoparticles

       Atmospheric aerosols and nanoparticles -Modification of regional air quality, the radiation balance and climate
       Atmospheric aerosols are gaseous dispersions of ultrafine particles (black carbon, organic compounds, ions, minerals), which interact with radiation, and modify cloud structure and precipitation patterns. We approach this problem at multiple scales, through fundamental laboratory-based studies, field experiments and chemical transport and climate modeling.
       Themes:
       * Inter-annual and seasonal variability in atmospheric aerosol distributions and induced changes in the radiation balance.
       * Source resolution of anthropogenic aerosols and mitigation strategies through technology substitution.
       * Strategies to leverage climate benefits from regional air quality management.
       Approaches:
       * Emissions modelling, chemical transport and climate modelling. Integration with observational data from lidar, satellite and ship sensors.
       * Laboratory measurements of microphysical, chemical, optical and hygroscopic properties of combustion particles.
       * Mie theory models for absorption calculations from measured size and chemical composition.
       * Multivariate source identification models.
       There is a fundamental lack of knowledge on formation and effects of atmospheric aerosols and their ultrafine particle fraction (UFP). There is lack of information on how atmospheric nano-particles form and grow to sizes that can serve as cloud condensation nuclei and affect Earth?s albedo and climate. We propose to conduct atmospheric simulation studies with two state-of-the-science models: the global general circulation model of the Laboratoire de Meteorologie Dynamique (LMD-ZT) and the regional-scale chemical transport model of The University of Iowa (STEM-2K1). These models have been used extensively in regional air quality and climate studies in Asia and have been evaluated against data from large field campaigns in the region. The models include a detailed treatment of gas and aerosol chemistry, deposition and wet removal processes. They treat various aerosol constituents like black carbon, organic matter, inorganic soluble species (sodium, potassium, calcium, magnesium, ammonium, sulfate, nitrate, and chloride) and volatile species (ammonium, nitrate, carbonate, and chloride). While the global model has a detailed radiation transfer scheme but coarse spatial resolution, the regional model contains more detailed atmospheric and aerosol chemistry and can be used over nested domains with resolutions as fine as 5 km. Emissions for these models have been developed in our group?s emissions modelling activity and reflect fuel composition, technology use and pollution control in current practice. Regionally important emission sources like the low-temperature combustion of biomass fuels and agricultural waste burning have been represented in detail. We will address the following problems:
       * Source resolution of anthropogenic aerosols and mitigation strategies through technology substitution.
       * Capacity building for long-term climate simulations with in-situ aerosols, currently not in practice in the Indian climate modelling community