Abstract View
Submicron Soot Microphysical and Chemical Signatures from Detonations of High Explosive Composites in Controlled Atmospheres
ALLISON AIKEN, Rachel Huber, Andrew Schmalzer, Mark Boggs, James D. Lee, Kyle Gorkowski, Manvendra Dubey, Los Alamos National Lab
Abstract Number: 602
Working Group: Carbonaceous Aerosol
Abstract
Carbonaceous particles are lofted and transported long distances in the atmosphere that can impact climate and human health at local, regional and global scales. Submicron particles containing soot are formed during detonation of high explosives. Chemical and microphysical properties of ambient soot particles depend on fuel and source conditions as shown for biomass burning and fossil fuel combustion that have been studied for decades. In contrast, analogous dynamic aerosol processes of explosions and high fluence fires have been less studied. Here, we compare detonation soot aerosol physical, optical and chemical properties with biomass burning and fossil fuel emission sources in the lab and field. Carbonaceous signatures such as the presence of fullerenes and polycyclic aromatic hydrocarbons are compared with more common ambient and laboratory-generated soot surrogates. Offline analysis of inorganics and metals validate SP-AMS trace-metal detection and our interpretation of water uptake properties.
We utilize sensitive and selective ambient aerosol techniques to identify soot from two well-known high explosive composites (1) Comp-B: trinitrotoluene (TNT) and 1,3,5-Trinitro-1,3,5-triazinane (RDX) and (2) PBX 9501: 1,3,5,7-Tetranitro-1,3,5,7-tetrazoctane (HMX). Results from the Soot Particle Aerosol Mass Spectrometer (SP-AMS), Single Particle Soot Photometer (SP2), Scanning Mobility Particle Sizer (SMPS), Three-wavelength Photoacoustic Soot Spectrometer (PASS-3) and a custom RH-controlled Cavity-Attenuated Phase Shift-Single Scattering Albedo PM monitor (H-CAPS-PMSSA) at 450 nm are presented.
The soot sampled had small mobility diameters (< 100 nm) and unique optical and chemical signatures depending on the explosive composite composition, detonation atmosphere (e.g., Argon, air) and pressure. Single Scattering Albedos (SSA) from 0.3 to 0.8 and Absorption Angstrom Exponents (AAE) from 0.5 to 2.0 were measured across 405 to 870 nm wavelengths and were found to depend on the explosive composite composition and detonation conditions.