Atmospheric Tar Balls: Particles From Biomass and Biofuel Burning
Abstract
'Tar balls,' amorphous carbonaceous spherules that are locally abundant in the tropospheric aerosol through biomass and biofuel burning, form a distinct group of particles, readily identifiable with electron microscopy. They differ from soot in lacking a turbostratic microstructure, and their morphology and composition (~90 mol% carbon) renders them distinct from other carbonaceous particles. Tar balls are abundant in slightly aged (minutes to hours) biomass smoke, indicating that they likely form by gas-to-particle conversion within smoke plumes. Although the material of tar balls is initially hygroscopic, the particles become largely insoluble through free radical polymerization of their organic molecules. Tar balls are primarily externally mixed with other particle types, and they do not appreciably increase in size during aging. When they coagulate with water-bearing particles, their material may partly dissolve and no longer be recognizable as distinct particles. Tar balls may slightly absorb sunlight. They are a widespread and previously unrecognized type of carbonaceous (organic) atmospheric particle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFM.A22F..06P
- Keywords:
-
- 0305 Aerosols and particles (0345;
- 4801);
- 0315 Biosphere/atmosphere interactions;
- 0322 Constituent sources and sinks;
- 0345 Pollution: urban and regional (0305);
- 0365 Troposphere: composition and chemistry