NARSTO PM Assessment Chapter 5: Spatial and Temporal Pattern Total PM and Haze Pattern over N' Ameri

1
NARSTO PM AssessmentChapter 5 Spatial and
Temporal PatternTotal PM and Haze Pattern over
N. America

• Section Contents
• Fine and Coarse PM Concentration - IMPROVE
• Chemical Speciation of the Fine Mass
• PM2.5 Concentration FRM AIRS
• Seasonal PM2.5 Concentration FRM AIRS
• Seasonal Visibility Trends Maps 1980-1995
• Eastern US Visibility Trends

2
Fine and Coarse PM Concentration

• Based on IMPROVE, See Sisler Malm

• The remote IMPROVE sites show that the annual
  average Fine Mass is highest over the Eastern US
  (gt 10 ug/m3).
• The Coarse particle mass is (PM10-PM2.5) is
  highest along the coast and in the dust belt
  from Texas to the Dakotas.

3
Chemical Speciation of the Fine Mass

• Based on IMPROVE
• See Sisler Malm

• Over the remote Eastern US, sulfates dominate the
  Fine Mass
• The Southeast is also influenced by smoke
  (organicsLAC) and dust.
• Over the West, organics, nitrates and dust
  dominate

4
PM2.5 Concentration FRM AIRS

• There is about one year of data available from
  the new EPA FRM PM2.5 network.
• Most of the sites are near urban areas with some
  regional coverage.
• The highest annual PM2.5 concentrations (gt21
  ug/m3) are seen over the air basins of
  California.
• A much broader region of high PM2.5 (gt15 ug/m3)
  covers the mid-section of Eastern US.

5
Seasonal PM2.5 Concentration FRM AIRS

• The East, the PM2.5 concentrations peak in the
  summer season.
• In the PM2.5 hotspots of California and Oregon,
  the highest fine particle levels occur in the
  cold season, November-February

6
Seasonal Visibility Trends Maps 1980-1995

• In the period 1980-95, the visibility has
  improved throughout the US.

 
7
Eastern US Visibility Trends
90th Percentile - Top Trends 75th Percentile -
Bottom Trends

• Trends of the summertime 90th and 75th percentile
  light extinction for the eastern, northeastern
  and southeastern U.S. from 1980-95. The
  confidence level for each trend is based on the
  two sided Student's t-distribution.