Spherical tarball particles form through rapid chemical and physical changes of organic matter in biomass-burning smoke

• DOI: 10.1073/pnas.1900129116
• Publication Date: 2019-09-05T21:45:32Z
• Authors: Kouji Adachi; Arthur J. Sedlacek; Lawrence Kleinman; Stephen R. Spring...; Jian Wang; Duli Chand; John M. Hubbe; John E. Shilling; Timothy B. Onasch; Takeshi Kinase; Kohei Sakata; Yoshio Takahashi; Peter R. Buseck
• Keywords: Particle (ecology); Sphericity

Biomass burning (BB) emits enormous amounts of aerosol particles and gases into the atmosphere thereby significantly influences regional air quality global climate. A dominant particle type from BB is spherical organic commonly referred to as tarballs. Currently, tarballs can only be identified, using microscopy, their uniquely shapes following impaction onto a grid. Despite abundance potential significance for climate, many unanswered questions related formation, emission inventory, removal processes, optical properties still remain. Here, we report analysis that supports tarball formation in which primary undergo chemical physical processing within ∼3 h emission. Transmission electron microscopy reveals number fractions ratios N O relative K, latter conserved tracer, increase with age more-spherical on substrates had higher K. Scanning transmission X-ray spectrometry energy loss analyses show these changes are accompanied by compounds contain nitrogen carboxylic acid. The results imply sphericity substrates, correlates surface tension viscosity, contribute during aging smoke. These findings will enable models better partition contributions radiative forcing and, so doing, help constrain events.