Source Apportionment of
PM2.5 Speciation Trends Data
Conducted by:
Battelle (Basil Coutant) with
Sonoma Tech. (Hillary Main) and
Dyncorp (Katherine Brehme)
Funded by:
OAPQS, EMAD
Summarized here by:
Rich Poirot, VT DEC 9/27/02
Technical Approach
• Techniques applied
– PMF (UNMIX) to apportion PM2.5 into seven sources
– local wind analysis to verify local sources
– back trajectory analysis for transport, may miss local
sources (500km start height, 3hr, 80km cells)
• 3 Urban sites
– St Louis, MO
– Bronx, NY
– Houston, TX
• Limited amount of data (~1 year)
Bronx, NY – site attributes
•
•
•
•
Bronx Garden site
located in the middle of the Bronx
heavily populated urban area
local sources
–
–
–
–
–
mobile emissions
fuel oil (particularly in the winter)
two oil-fired power plants
street cleaning
marine influence
Summary of Source Identification for Bronx, New York
Source
Number
Preliminary
Identification
Notes
Key Species and Profile Comments
Key species include NH4, OC, SO4, mass. This is
consistent with the regional
background/transport sources observed in all SA
analyses done in the Northeast.
1
Secondary (summer)
sulfate
Summer peak
2
Fuel oil
Winter peak
Key species include EC>OC, Cl, V, Ni. V and Ni,
winter peak lead to fuel oil combustion.
3
Sea spray
Note FRM/PM2.5
inconsistency
Key species include Na, K, Cl, several metals.
Odd profile with some indication of general
industrial source.
4
Mobile - tire wear
combination.
Also inconsistent
FRM, PM2.5.
Key species include Na, OC>EC, several metals.
Possible mobile source profile including tire
wear.
5
Industrial? (Oil fired
power plant ?)
Winter peak
6
Nitrate
Winter peak
Key species include K, NO3, NH4, mass. This is
consistent with a regional nitrate signature.
7
Dirt
Most likely from street
cleaning
Key species include K, Al, Ca, Si, Ti. Good match
with paved road dust.
Key species include Zn, Ca, Se, Ni, Pb, OC>EC.
Winter peak. Note that the sulfur and V
contributions are low while Zn, Pb, Cu, and Ca
are enhanced.
Summary of Source Apportionment for Bronx
Source
Apportioned
mass (g/m3)
Pollution Rose
Notes
5.29
PA, Western VA, Eastern MA,
Eastern WV, Atlantic Ocean
Uniform
Back trajectory is consisten
with known source
locations.
Fuel oil
1.22
NY City and east, parts of VA,
NC, and SC
North, West,
and South
Basically consistent, the SC
area may be from oil-fired
power plants.
Sea spray
0.30
Atlantic ocean
Mobile-tire
wear
combination
2.49
NY, NY City, MA, CT, VA, PA
Secondary
sulfate
Industrial
Nitrate
Dirt
Back Trajectory
NE-SE
East and SE
Back trajectory is consisten
with major highways.
1.82
Central OH, Southern PA, MD,
NC-VA
SW to NW
Back trajectory is consisten
with expected source
locations.
4.09
Central OH, PA, MD, NC, SC, ME
SE, S to W
Source location is
uncertain.
0.97
Canada, NY City, Central PA
down through VA, Mining areas
of OH and WV
SW, NNE, SSE
Most likely street
cleaning, other area
correspond to farming
and mining locations.
Relative Composition for Source 1 at the Bronx Site
Sulfate
Ammonium
Organic Carbon
Key species include NH4, OC, SO4, mass. This is consistent with the regional
background/transport sources observed in all SA analyses done in the Northeast.
Source 1 - Secondary sulfate has a summer peak
Source contribution function for Source 1 at the Bronx site indicates 1.
sulfate sources in OH, WV, and PA near Wheeling, WV, a region running
southwest through VA, area along Lake Erie, and area over Massachusetts.
2.
corresponds to clusters of utility plants with large SO2 emissions.
Source 6 - Nitrate probability plots for Bronx site do not correspond nearly as well,
1.
may be due to semi-volatile nature of nitrate, meteorological influence
2.
indicate a source in SC, which corresponds to utility plant locations
St. Louis – site attributes
• Blair Street site
• located near the intersection of several highways
– mobile emissions should be a major component
•
•
•
•
•
•
several municipal incinerators
zinc smelter
large lead smelter
steel mill
cement manufacturing
limestone quarrying in the area.
Summary of Source Identification for St. Louis, Missouri
Source
Number
Preliminary
Identification
Notes
Key Species and Profile
Comments
1
Zinc refinery
Facility near the site (and several municipal
waste incinerators)
Cl, Zn, EC>OC.
2
Copper Smelting
Chemetco (secondary copper smelter in
Alton, Illinois)
Cu combined with OC, EC
3
Coal combustion
Consistent with power generation. Does
not show a seasonal trend.
Mass, OC, NH4, SO4, Se.
4
Steel production
Grant City Steel may contribute to high Fe
levels.
Cl, Cr, Fe, Mn, Ni. Good match
with profile.
5
Nitrate
NOx from power plants. Power plant to the
SE
Key species include NO3, mass,
NH4.
Crustal
High Ca, K relative to typical crustal.
Possibility cement plant or limestone
quarrying, but peaks probably coincide with
agricultural activity.
Al, Si, Good match to crustal
profile.
Mobile sources
High Pb possible because of residue (in
road dust) from old Pb smelter emissions
and hauling w/o tarps.
Br, OC>EC, Pb.
6
7
Summary of Source Apportionment for St. Louis
Source
Zinc
Apportioned
mass (g/m3)
0.85
Back Trajectory
IL, KY, Western TN
Pollution
Rose
N-NNW and
SE
Copper
Smelting
0.59
All distant, Central TX-OK, KS, NE
NE-SE
Coal
combustion
5.74
OH River, WV, OH, IN, KY, TN, AR,
MS
Uniform
Steel
production
0.76
OH River, N IN, TX, AR-TN-MS,
Atlanta
Nitrate
5.02
Atlanta, OH River and NW
Crustal
1.43
Central MO-AR-N LA-NW TX-W
OK
Mobile
sources
2.92
Distant
NE-E
Northerly
S-SW
Uniform
Notes
Granite City IL steel
production is too close to
be indicated by the back
trajectories.
The Alton IL cooper
smelter is too close to be
indicated by the back
trajectories.
Locations are consistent
with known sources.
Granite City Steel is too
close to be indicated by the
back trajectories.
Source location is
unknown due to
confounding factors.
Most likely from
agricultural activities.
The local mobile sources
should dominate and are
too close to be indicated
by the back trajectories.
St Louis - Coal Combustion
(Sulfate)
- notice the direction of the curl
on the trajectories from the
20 percent worst days (red) for
the sulfate source that pass
through Kentucky
-source contribution plot may be
indicating sulfate sources in
Kentucky because of these
trajectories around high pressure
(indicated by clockwise wind
flow).
- results in pollutants trapped near
the surface.
- not surprising that source areas
are indicated to the south of the
utility plants along the Ohio River
and along the Indiana-Illinois
state line
St Louis - Nitrate
On the other hand….
- high nitrate days are on
days with winds out of
Canada (red).
- association with these
winds is probably not
indicating source
locations, but rather
conditions favorable for
the nitrate (cool
temperatures?).
Houston – site attributes
• Aldine Road site
• heavily impacted by the ship channel
• expected to be affected by sources that
would be associated with an urban area
• i.e., mobile emissions should be significant
Summary of Source Identification for Houston, Texas
Source
Number
Preliminary
Identification
1
Dirt
2
Fireworks
3
Industrial
4
Secondary
OC/mobile
5
Marine Nitrate source
6
Mobile/Mn
source
7
Secondary
sulfate from
fossil fuels
Notes
Key Species and Profile Comments
Usual crustal elements.
The peak is for July 4.
July 5 is about half-way
down.
Key species include K. Other small blips of this profile in
the winter may be consistent with wood smoke.
Key species include Zn, Cl, Cr, Ni, other metals. Other
profiles to consider include hogged fuel boiler, industrial
average manufacturing.
This site is in a
residential
neighborhood with
freeways to the north.
Key species include OC>EC, NH4, Ca, Mass.
Inconsistent profile –
the mass estimate is too
low – sulfur/sulfate do
not match up well.
Key species include NO3, Na, Cl. This could be a marine
influenced profile from the gulf or bay on which sodium
nitrate has formed as the air parcels pass over the
emissions sources. That would explain the absence of
ammonium and sulfur.
The Mn signature may
be a result of
substituting MDL/2 for
Mn.
Key species include Mn.
This appears to be a general combustion signature
including oil (V) and coal (Se). Se from coal combustion
is a possibility as Texas Lignite operates upwind of
Houston.
Summary of Source Apportionment for Houston
Source
Dirt
Fireworks
Apportioned
mass (g/m3)
0.77
0.49
Industrial
0.87
Secondary
OC/mobile
5.19
Marine-Nitrat
e source
Mobile-Mn
source
Secondary
sulfate from
fossil fuels
0.29
1.04
5.54
Back Trajectory
Pollution
Rose
Notes
Local/Met related
S-W
Local/Met related
W-NW
Local/Met related
East-South
Local/Met related
Northerly
Local/Met related
SE and NW
The bi-directionality could be from
a sea breeze effect.
Local/Met related
SE and NW
The bi-directionality could be from
a sea breeze effect.
Local/Met related
Slightly E-SE
This is essentially a one-time, local
source.
The pollution rose and back
trajectories are not consistent.
Houston – Secondary Sulfate
1. associated with clockwise airflow
2. associated with high-pressure zones rather than an area
3. virtually all trajectories enter from the southeast, over the shipping channel
4. source contribution function is always lower than would be expected for a
source location
Houston – Marine Nitrate
1.
2.
3.
Associated with airflow from
the Gulf and airflow out of
Canada (red).
As with the other sites, the
flow out of Canada is
probably just associated with
conditions favorable to
nitrate formation. Flow over
the Gulf explains the marine
component of the profile.
Source contribution function
is very low, which may
indicate that the sources are
local or, more likely, the
relationship is from favorable
meteorological conditions.
Conclusions
• Combination of source apportionment techniques,
local wind analysis, and back trajectory analysis
provides meaningful results.
• Limitations –
– Sufficient data
– Local low level winds, highly variable
– Back trajectories – coarse resolution, may miss local
sources
– Lack of error estimates
• Next Steps – add DC and Milwaukee sites