NARSTO PM Assessment Chapter 5: Spatial and Temporal Pattern Approach to Spatial and Temporal Patter

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NARSTO PM AssessmentChapter 5 Spatial and
Temporal PatternApproach to Spatial and
Temporal Pattern Chapter

• Section Contents
• Aerosol Types Dust, Smoke and Haze
• General Features of North America
• Atmospheric Residence Time and Transport
  Distance
• Spatial-Temporal Pattern Chapter Structure

Direct questions to Rudolf B. Husar
rhusar_at_me.wustl.edu
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Aerosol Types Dust, Smoke and Haze

• Aerosol are composed of multiple types. Each type
  may be considered a different pollutant since it
  has its own class of sources, aerosol properties
  and associated with different effects.
• In other words, dust, smoke and haze have no more
  commonalities then CO, NOx and SO2 but the happen
  to be lumped by the current regulations.
• For this reason, the chapter will discuss the
  pattern of aerosol components (types) first and
  then the total aerosol pattern.
• The aerosol population is grouped into three
  types
• DUST SOIL
• SMOKE ORGANICS SOOT
• HAZE SULFATE NITRATE
• FMASS DUST SMOKE HAZE
• These aerosol types correspond to the IMPROVE
  aerosol types but further aggregated for reducing
  complexity The IMPROVE teps are
• SULFATE 4.125S Ammonium sulfate
• NITRATE 1.29NO3 Ammonium nitrate
• ORGANICS 1.4(O1O2O3O4OP) 1.4 various
  organics (OMC)
• SOOT E1E2E3OP Light absorbing carbon (LAC)
• SOIL 2.2AL2.49SI1.63CA2.42FE1.94TI
  Crustal elements
• FMASS SULFATE NITRATE LAC OCM
  SOIL Reconstructed fine mass
• CMASS MT-MF CoarsePM10-FMASS

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Aerosol Size Chemical Composition

• Issue This Figure does not belong in the Spatial
  Temporal Pattern (STP) chapter of the NARSTO PM
  doc but I am offering it for consideration by the
  other authors.
• The figure was generated by an international
  group as part of the IGAC Integration and
  Synthesis workgroup.
• The process of figure creation can be found the
  here.

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General Features of North America

• Issue Somewhere in NARSTO PM we could use some
  general description of the continental features.
  Examples are here. I will be happy to help if
  needed. If not we can skip these. RBH

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Atmospheric Residence Time and Transport Distance

• Froelich schem. PM2.5 residence time increases
  with height.
• Within the atmospheric boundary layer (the lowest
  1-2 km), the residence time is 3-5 days.
• If aerosols are lifted to 1-10 km in the
  troposphere,(e.g. by deep convection at fronts or
  convergence zones) they are transported for weeks
  and many thousand miles before removal.

• Jaenicke plot Ultrafine 0.1 m coagulate while
  coarse particles above 10 m settle out more
  rapidly.
• PM in the 0.1-1.0 m size range has the longest
  residence time because they neither settle, nor
  coagulate.

• Atmospheric residence time and transport distance
  are related by the average wind speed, say 5 m/s.
  
• Residence time of several days yields long range
  transport and more uniform spatial pattern.
• On the average, PM2.5 particles are transported
  1000 or more km from the source of their
  precursor gases.

• The residence time determines the range of
  transport. For example, given a residence time of
  4 days (100 hrs) and a mean transport speed of
  10 mph, the transport distance is about 1000
  miles.
• The range of transport determines the region of
  influence of specific sources.

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Aerosol Pattern at Different Spatial and Temporal
Scales

• The spatial and temporal distribution of aerosols
  can be described by the pattern at different
  scales
• The pattern of ambient concentration is
  determined by the pattern of their causal
  factors emissions, transport and chemistry.
• The spatio-temporal pattern of emissions,
  transport and chemistry may be different at each
  scale.
• Temporal and spatial pattern analysis of PM data
  is particularly useful for source identification
  and characterization.

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Spatial-Temporal Pattern Chapter Structure

• The main chapter grouping is by geographic scale
• Global
• Continental/Regional
• Subregional/Local
• Within each section, the pattern are described
  for
• Dust
• Smoke
• Haze
• Total (PM10, PM2.5, Bext, AOT)

Issue Once we all make our respective
contributions and see the chapter contents, it
may be good to revisit the the structure for
possible revisions. RHB