Atmospheric Chemistry Program Seminar

Recent Results and Upcoming Projects Investigating Aerosol Sources, Properties, Processes, and Fate by Jose Jimenez,
ANYL faculty, CU Boulder
"This fall ½ seminar provides an opportunity to introduce our group and its upcoming opportunities to the starting graduate student class, as well as to provide a summary of key results to the ANYL division as a whole. Our group’s research focuses on understanding the sources, properties, transformations, and sinks of submicron aerosols (and of the gases that interact with them), which have major effects on human health and climate.
In this talk I will briefly present results from different projects over the last year, especially those most relevant to incoming student opportunities. I will introduce our aircraft research program, where we are currently participating in the FIREX-AQ campaign sampling biomass burning smoke with the NASA DC8 aircraft. We are deploying an aerosol mass spectrometer (AMS) and, for the first time, an extractive electrospray (EESI) MS, with excellent results. I will also summarize results from the ATOM campaign, the first to sample the global remote troposphere systematically with vertical coverage. In particular global models are found to predict organic aerosols (OA) ok, but for a combination of wrong reasons as primary OA (POA) is greatly overestimated. On the other hand, models tend to predict pH which is substantially higher than the observations, with a pH ~ 0 being typical of the remote troposphere. A meta-analysis of large urban studies shows that urban secondary OA (SOA) leads to ~320,000 excess deaths per year globally, and should be the target of future regulations. The budget of organic carbon of indoor air is presented and compared to that of outdoor studies. Finally, fundamental measurements of the organic accommodation coefficient are presented using a new chamber technique.
Potential opportunities in our group involve the CalNexT campaign studying urban SOA in Los Angeles, studies of indoor air chemistry and surface interactions, analysis of aircraft campaign data and participation in future campaigns, and chamber experiments targeting both fundamental processes and signatures of urban SOA sources. Modeling tools such as KinSim and GECKO-A can be applied to the different problems as needed."
and
Atmospheric nanoaerosols: An instrument for chemical analysis of freshly nucleated particles and their formation from biogenic organic precursors by Andrea Wagner,
ANYL Postdoctoral Researcher, CU Boulder, Volkamer Group
"A large fraction of atmospheric aerosol particles are formed via new particle formation from the gas phase. But the chemical analysis of freshly nucleated particles smaller than 30 nm is challenging due to their tiny mass. In this talk I present a new instrument that, in combination with a chemical ionization time-of-flight mass spectrometer, analyzes these nucleation mode particles. The measurements are size-resolved and parallel to gas-phase analysis. Additionally, mechanisms for the formation of particles from purely biogenic organic precursors in chamber measurements are presented."