Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Alessandro Franchin

Research Interests

Climate change, air quality, Aerosol composition, aerosol optical properties, aerosol-cloud interactions, mass spectrometry, instrument development.

Current Research

My current research focuses on the chemical composition and evolution of aerosols. How aerosols from urban sources and wildfires can affect air quality and climate.

Urban aerosols and air quality. Wintertime is a critical time for air quality. In mountain valleys, cold temperatures can trap pollutants close to the surface favoring buildup of aerosols. This is the case in many parts of the world, for example in the North China Plain, in the Po Valley in Italy, in the Central Valley in California and in the valleys neighboring the Great Salt Lake in Northern Utah. I participated in the Utah Winter Fine Particulates Study (UWFPS) in Jan - Feb, 2017 with the goal to understand wintertime particulate matter pollution in northern Utah. I flew on a NOAA Twin Otter aircraft equipped with our semi-custom build Aerosol Mass Spectrometer, an Ultra High Sensitivity Particle Spectrometer and other trace gas instruments. Using this data set, we learned that the aerosol during these episodes is almost exclusively composed of ammonium nitrate and its formation is limited by nitric acid availability, which in turn is most sensitive to reductions in VOCs. These results have important implications for pollution control strategies in the valley.

 

Biomass burning aerosol chemical composition and optical properties in controlled burns. Wildfires are an increasing source of aerosols in the western U.S. Their intensity and frequency are increasing due to climate change and their effect on climate and air quality is more and more severe. I participated in the first stage of the Fire Influence on Regional and Global Environments Experiment (FIREX) at the Missoula Fire Sciences Lab in Oct - Nov 2016. My research focused on investigating the link between optical properties and chemical composition of biomass burning aerosol, using our Aerosol Mass Spectrometer.

 

Biomass burning aerosol chemical composition and optical properties in wildfires. During the summer of 2019, I participated in the second stage of the Fire Influence on Regional and Global Environments Experiment (FIREX). I flew on a NOAA Twin Otter aircraft equipped with a High-Resolution Aerosol Mass Spectrometer, an Ultra High Sensitivity Particle Spectrometer and a Continuous Light Absorption Photometer. The data collected in this campaign will be analyzed in light of the knowledge gathered in the first stage of FIREX at the Missoula Fire Sciences Lab. We will highlight the link between optical properties and chemical composition in biomass burning aerosol and the difference between how they transform downwind during the day and during the night.