Probing the Surfaces of Atmospheric Organic Particles and the Implications for Climate Change, Air Quality, Visibility and Bioavailability
Abstract
Atmospheric reactions are intimately involved with climate change, and in addition, they lead to changes in toxicity and bioavailability of species emitted into the air. For example, airborne toxics to which U.S. Army troops are exposed depend not only on emissions but also on the chemical transformations that occur in air subsequently. Such reactions can also lead to changes in the interactions with soils and aqueous media by altering the chemical and physical properties of the species emitted and/or formed in the atmosphere. These impacts on environmental quality, health and climate can have direct impacts on the Army mission. Particles are particularly important in this regard, especially how they form and grow to - 100 nm where they impact visibility, serve as cloud condensation nuclei to impact climate, and also efficiently reach the deep lung. Organic particles formed by chemical reactions of gaseous precursors (secondary organic aerosol, SOA) dominate the composition in most locations. There are chemical reasons... but virtually no data... that suggest that the composition of the surface layer of organic particles differs from the bulk. This is critical since it is the surface that incoming gases interact with first. and it will interact directly with biological systems such as the skin, eyes, and respiratory tract The goals of the proposed research are to elucidate the chemical composition of the surface layers of atmospherically relevant organic particles and compare these 10 their average bulk composition. The proposed research involves laboratory studies in which (I) well defined model systems with a core and coating of well-defined thickness but different chemical composition will be generated and characterized;(2) SOA particles formed from a variety of organic precursors, both natural and anthropogenic, will be generated and the physical properties such as size distributions measured; and (3) the surface and bulk composition of these two sets of model systems will be probed using new mass spectrometry {MS) approaches. These include DART-MS (direct analysis in real time MS). AP-MALDI-MS (ambient pressure matrix assisted laser desorption ionization MS), MAIV¥MS (matrix assisted ionization vacuum MS); LTP-MS (low temperature plasma MS) and EESI-MS (extractive electrospray ionization MS). The application of many different approaches and use of different mode.1 systems will be key to obtaining a quantitative understanding of the surface layer composition and bow it differs from the bulk. The results of the proposed research will be the development of a quantitative understanding of the composition of the surface of complex organic particles. This will facilitate assessment of the role of organic particles in reducing visibility and in climate change via altering cloud formation and properties. In addition, it will provide insight into how atmospheric reactions determine the interactions of particles with biological systems and their bioavailability. These data will provide an important fundamental scientific basis for assessing a wide range of potential impacts on Army operations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 11, 2018
- Source ID
- W911NF1710105
Entities
People
- Barbara J. Finlayson-Pitts
Organizations
- Army Contracting Command
- United States Army
- University of California, Irvine