Bulletin of the American Physical Society
Mid-Atlantic Section Fall Meeting 2020
Volume 65, Number 20
Friday–Sunday, December 4–6, 2020; Virtual
Session B03: Atmospheric Chemistry and Aerosols I |
Hide Abstracts |
Chair: Ogochukwu Enekwizu, NJIT |
Friday, December 4, 2020 2:00PM - 2:36PM |
B03.00001: Atmospheric Aerosol Chemistry: Climate and Air Quality Invited Speaker: Douglas Worsnop Despite much effort in past decades, uncertainties in both climate impacts and health effects of atmospheric aerosols remain large. During the last twenty years, aerosol mass spectrometry (AMS) has shown that sub-micron aerosol chemical composition is roughly 50:50 inorganic and organic worldwide, with secondary highly oxidized organics dominating the latter. Parallel application of chemical ionization mass spectrometry (CIMS) has provided the first observation of molecular cluster ions involved in atmospheric nucleation, including detection of highly oxidized multifunctional (HOM) organics in the gas phase. These results will be discussed in the context of their impact on atmospheric aerosols, air quality and climate; from the boreal forest to Chinese megacities. Aerodyne Research, Inc.; INAR (Physics), University of Helsinki [Preview Abstract] |
Friday, December 4, 2020 2:36PM - 3:12PM |
B03.00002: What processes are responsible for the growth of atmospheric nanoparticles? Invited Speaker: James Smith New particle formation is the spontaneous creation of new nanometer-sized particles in the atmosphere. Observations spanning from megacities to isolated forests show that these events can occur frequently and extend for hundreds of square kilometers. While the impacts of these events are not well understood, they are often the dominant source of particles in the remote regions and could play a crucial role in the Earth's climate by regulating the number and activity of cloud condensation nuclei (CCN). This effect of aerosols on cloud properties is recognized in the Fifth IPCC Assessment Report as the largest single contributor to uncertainty in predicting climate change. Since cloud droplet activation normally occurs on particles of about 100 nm in diameter, the key to understanding the impact of new particle formation on climate lies in the ability to predict the growth of newly formed particles. In this talk I will describe recent efforts to understand the species and mechanisms that are responsible for the growth of nanometer-sized particles. I will describe measurements performed with the Thermal Desorption Chemical Ionization Mass Spectrometer, an instrument capable of real time measurements of the molecular composition of nanoparticles as small as 6 nm in diameter at time resolutions of \textasciitilde 20 minutes. Highlighting observations from Mexico City and the Finnish boreal forest, as well as lab and modeling studies, I will demonstrate the importance of organic acids, amines, inorganic acids, and highly oxidized organic compounds in atmospheric nanoparticle growth. [Preview Abstract] |
Friday, December 4, 2020 3:12PM - 3:48PM |
B03.00003: Wildfires and Their Contribution to Climate Change Invited Speaker: Arthur Sedlacek Aerosols emitted from wildfires and agricultural burns, collectively referred to as biomass burning aerosols (BBA), perturb Earth's climate through ``direct'' effects (scattering and absorption of incoming shortwave radiation), ``semi-direct'' effects (evaporation of cloud drops and modification of atmospheric dynamics), and ``indirect'' effects (influencing cloud formation and precipitation). These events are an important source of emitted primary and secondary aerosol particles providing an estimated 50{\%} of anthropogenically-influenced fine carbonaceous particles and \textasciitilde 40{\%} of the global atmospheric inventory of black carbon (BC) -- a warming agent second only to CO$_{\mathrm{2}}$. Additionally, these events generate light-absorbing organic compounds, known as brown carbon (BrC). The overall effect of these BBA emissions on the atmospheric radiation balance, either forcing the atmosphere to heat or cool, depends on their abundance, cloud-forming activity, and complex refractive index. Their climate forcing impacts are governed by these particle properties and their temporal and spatial extents during their lifecycle. By combining aircraft observations on the near-source evolution (\textless 5 hrs) of BBA particles with measurements on very aged (1-2 weeks) BBA plumes that have been transported 1000's of kilometers across oceans to other continents, we can, for the first time, begin to examine how biomass burn aerosols change throughout their lifecycle. The lifecycle of BB aerosols from near-source to near-global extents will be discussed, focusing on the evolution of their chemical, microphysical, and optical properties. Primarily utilizing measurements of black carbon containing particles, we track observed changes in BBA particle properties that provide insights into the processes affecting them as their environments change from local emission through long range transport. I will first introduce the importance and associated complexities of biomass burning. Next I will briefly discuss how measurements of these events are conducted and how uniquely combining different measurements can provide new insights into how atmospheric processing can alter the compositional, microphysical and optical properties of BBA particles. Finally, I will give an overview of the lifecycle of BBA particles and their properties. [Preview Abstract] |
Friday, December 4, 2020 3:48PM - 4:00PM |
B03.00004: Morphology of Atmospheric Particles Claudio Mazzoleni Atmospheric particles have highly diverse physical and chemical properties that determine the particles’ life-cycles, and impacts on climate and air quality. Key properties include size distribution, chemical composition, optical coefficients, and affinity for water that affect the particles’ interactions with clouds and radiation. These properties are often determined for a population of particles; however, under an electron microscope, no two particles look alike, each exhibiting a unique shape, with several components often mixed in different geometric configurations. These geometrical, structural, and topological properties – the particle morphology – affect how the particles behave in the atmosphere, including how efficiently they nucleate water and ice, and how they interact with solar radiation. In this talk, I will show examples of the morphology of individual particles, and I will discuss how the morphology evolves, and the impacts that morphology can have on the particles’ interactions in the atmosphere. I will present results from ambient and laboratory studies, including analyses of samples from a remote high-elevation station in the Azores, and from experiments performed in the turbulent cloud chamber facility at Michigan Technological University (the Pi-chamber). [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700