The Atlanta Aerosol (in 10 min)

1
The Atlanta Aerosol(in 10 min)

• Rodney Weber
• Georgia Tech
• rweber_at_eas.gatech.edu
• 404-894-1750,
• www.aerosols.eas.gatech.edu

2
Atlanta and the PM2.5 NAAQS
From Eric Edgerton, ARA Inc.
Atlanta
Yorkville rural pair
3
Aerosol Chemistry

• Need aerosol chemistry to study PM
• sources
• health effects

• PM2.5 Mostly
• Sulfate
• Carbonaceous
• Organic
• Elemental (Soot)

4
Sulfate Aerosol
SO2 from coal-fired power plants. (EPA Document
454-R-04-002) Industrial/Institutional energy
production,... Emissions also includes toxic
substances, e.g., mercury
5
Sulfate Aerosol
Local Sulfate
Regional Sulfate
Power plants lead to large localized PM
6
Surface PM spikes often driven by sulfate
40
High degree of short-term variability (PM2.5 can
double in a few hours)
24 h vs 1 h avg. Jefferson Street, Atlanta
(rain)
(rain)
7
Sulfate Aerosol Summary

• Sulfate is a large fraction of Atlanta PM2.5
• implications for meeting NAAQS.
• Characterized by regional w/ superimposed local
  emissions.
• Possible links between transient PM and
  Myocardial Infarction (Peters et al., Circulation
  2001, 103 2810-15)
• Transient PM not observed in 24-hr averages
• No hourly PM standard

8
Carbonaceous Aerosol
Primary (insoluble) Secondary (soluble)

• Organic and Elemental Carbon
• Mainly from internal combustion engines OC
  biogenic sources
• Also includes toxic substances, e.g., aromatic
  VOCs, PAHs, metals

9
Geographical - Carbonaceous
Exposure to Carbonaceous Aerosol and Proximity to
Highways
Georgia Tech vs 75/85
Georgia Institute of Technology (GIT) Roof top of
EST Building
Next to I-75/85 400 m from GIT and 1 m from
highway
V.S.
10
Georgia Tech vs 75/85
June 15-18, 2005
Uncertainty is 5, based on side by side
comparisons
11
7.8
4.5
4.7
4.3
0.5
(soot)
(Water-Soluble)
EC 9 times higher at road (EC is all
primary) OC 1.4 times higher at road (mainly due
to insoluble primary) WSOC Little difference
(WSOC is almost all secondary)
11
Atlanta vs Rural
Comparison on a larger spatial scale
Yorkville, GA 80 km west of GIT
Georgia Institute of Technology (GIT) Roof top of
EST Building
V.S.
12
Atlanta vs Rural
July 23-27, 2005
Directly emitted (primary) carbonaceous aerosol
higher in Atlanta Secondary (water-soluble)
organic carbon spatially uniform
13
Carbonaceous Aerosol

• 1. OC large fraction of Atlanta PM2.5
  -implications for meeting NAAQS.
• 2. Importance of location depends on what
  components of carbonaceous aerosol are health
  risks
• a) Primary components (primary OC EC - apparent
  risk)
• tends to be water-insoluble (pure HCs)
• spatially non-uniform
• sources fairly well known.
• b) Secondary components (health risk??, 60-75
  of OC in summer)
• tends to be soluble in water (oxygenated-HCs)
• spatially uniform
• source not well known (mainly unknown chemical
  comp.)
• linked to biogenic VOCs (terpenes/isoprene
  trees) ?
• linked to vehicle emissions ?
• Implications on how to regulate.