Mapping urban air pollution at the nanoscale – identifying sources of ultrafine particles (<100 nm) and sub-10 nm particles that can penetrate deep into lungs and even cross the blood-brain barrier. Using mobile measurement campaigns combined with atmospheric dispersion modeling (AERMOD) to pinpoint hotspots near roadways, airports, and industrial sources. These tiniest particles dominate particle number concentrations but remain largely unregulated – understanding their spatial distribution is critical for protecting public health, especially in environmental justice communities.

Characterizing aerosol fluxes using advanced techniques such as eddy covariance, gradient transport, and relaxed eddy accumulation, leveraging data from tower-based, airborne, and remotely sensed instruments.

Investigating how atmospheric aerosols – particularly mineral dust mixed with pollution – deliver bioavailable iron to iron-starved ocean regions, triggering massive phytoplankton blooms that draw down atmospheric CO₂. Using laboratory experiments and global climate models to understand how aerosol chemistry transforms insoluble iron minerals into forms marine organisms can use. This atmosphere-ocean connection affects both marine food webs and Earth’s climate through the biological carbon pump.

Developing algorithms to retrieve surface PM₂.₅ concentrations and chemical composition from satellite observations (MODIS, VIIRS, geostationary platforms). Creating tools to monitor air quality in regions lacking ground-based monitoring networks, enabling better exposure assessment for epidemiological studies. Combining satellite aerosol optical depth retrievals with meteorological data and atmospheric models to provide near-real-time air quality information for vulnerable populations.

Measuring size- and hygroscopicity-resolved aerosol fluxes using eddy covariance techniques to understand how particles move between the atmosphere and surface. Applying these measurements to improve parameterizations in regional and global climate models (GEOS-Chem, WRF-Chem, CESM). Understanding aerosol lifecycle – from emissions through atmospheric processing to deposition – and their radiative impacts on weather and climate.

Characterizing atmospheric nucleation events that create billions of new particles from gas-phase precursors. Investigating how these freshly formed particles grow to sizes where they can affect human health and cloud properties. Combining measurements from field campaigns (ACE-ENA, EPCAPE) with aerosol microphysics models to understand the chemical and physical processes controlling particle formation and growth in different environments.