100 research outputs found
Meteoritic rutile
Presence of titanium oxide in rutile of various meteorite
THE GREEN OCEAN AMAZON EXPERIMENT (GOAMAZON2014/5) OBSERVES POLLUTION AFFECTING GASES, AEROSOLS, CLOUDS, AND RAINFALL OVER THE RAIN FOREST
The susceptibility of air quality, weather, terrestrial ecosystems, and climate to human activities was investigated in a tropical environment.Peer reviewe
Formation and evolution of tar balls from northwestern US wildfires
Biomass burning is a major source of light-absorbing black and brown
carbonaceous particles. Tar balls (TBs) are a type of brown carbonaceous
particle apparently unique to biomass burning. Here we describe the first
atmospheric observations of the formation and evolution of TBs from forest
fires. Aerosol particles were collected on transmission electron microscopy (TEM) grids during aircraft
transects at various downwind distances from the Colockum Tarps wildland fire.
TB mass fractions, derived from TEM and in situ measurements, increased from
< 1 % near the fire to 31–45 % downwind, with little change in TB
diameter. Given the observed evolution of TBs, it is recommended that these
particles be labeled as processed primary particles, thereby distinguishing
TB formation–evolution from secondary organic aerosols. Single-scattering
albedo determined from scattering and absorption measurements increased
slightly with downwind distance. Similar TEM and single-scattering albedo results were observed
sampling multiple wildfires. Mie calculations are consistent with weak light
absorbance by TBs (i.e., m similar to the literature values 1.56−0.02i or
1.80−0.007i) but not consistent with absorption 1 order of magnitude stronger
observed in different settings. The field-derived TB mass
fractions reported here indicate that this particle type should be accounted
for in biomass burning emission inventories.</p
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