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

Source Number

Preliminary Identification

Notes Key Species and Profile Comments

1Secondary (summer) sulfate

Summer peakKey species include NH4, OC, SO4, mass. This is consistent with the regional background/transport sources observed in all SA analyses done in the Northeast.

2 Fuel oil Winter peakKey species include EC>OC, Cl, V, Ni. V and Ni, winter peak lead to fuel oil combustion.

3 Sea sprayNote FRM/PM2.5

inconsistency

Key species include Na, K, Cl, several metals. Odd profile with some indication of general industrial source.

4Mobile - tire wear combination.

Also inconsistent FRM, PM2.5.

Key species include Na, OC>EC, several metals. Possible mobile source profile including tire wear.

5Industrial? (Oil fired power plant ?)

Winter peakKey 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.

6 Nitrate Winter peakKey species include K, NO3, NH4, mass. This is consistent with a regional nitrate signature.

7 DirtMost likely from street cleaning

Key species include K, Al, Ca, Si, Ti. Good match with paved road dust.

Summary of Source Identification for Bronx, New York

Source Apportioned mass (g/m3)

Back Trajectory Pollution Rose Notes

Secondary sulfate

5.29PA, Western VA, Eastern MA, Eastern WV, Atlantic Ocean

UniformBack trajectory is consistent with known source locations.

Fuel oil 1.22NY 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 NE-SE  

Mobile-tire wear combination

2.49 NY, NY City, MA, CT, VA, PA East and SEBack trajectory is consistent with major highways.

Industrial 1.82Central OH, Southern PA, MD, NC-VA

SW to NWBack trajectory is consistent with expected source locations.

Nitrate4.09 Central OH, PA, MD, NC, SC, ME SE, S to W

Source location is uncertain.

Dirt 0.97Canada, NY City, Central PA down through VA, Mining areas of OH and WV

SW, NNE, SSEMost likely street cleaning, other area correspond to farming and mining locations.

Summary of Source Apportionment for Bronx

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.

Relative Composition for Source 1 at the Bronx Site

Ammonium Organic Carbon

Sulfate

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.

Source Number

Preliminary Identification

NotesKey Species and Profile

Comments

1 Zinc refineryFacility near the site (and several municipal waste incinerators)

Cl, Zn, EC>OC.

2 Copper SmeltingChemetco (secondary copper smelter in Alton, Illinois)

Cu combined with OC, EC

3 Coal combustionConsistent with power generation. Does not show a seasonal trend.

Mass, OC, NH4, SO4, Se.

4 Steel productionGrant City Steel may contribute to high Fe levels.

Cl, Cr, Fe, Mn, Ni. Good match with profile.

5 NitrateNOx from power plants. Power plant to the

SEKey species include NO3, mass, NH4.

6 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.

7 Mobile sourcesHigh Pb possible because of residue (in road dust) from old Pb smelter emissions and hauling w/o tarps.

Br, OC>EC, Pb.

Summary of Source Identification for St. Louis, Missouri

Source Apportioned mass (g/m3)

Back TrajectoryPollution

RoseNotes

Zinc 0.85 IL, KY, Western TN N-NNW and

SE

Granite City IL steel production is too close to be indicated by the back trajectories.

Copper Smelting

0.59 All distant, Central TX-OK, KS, NE NE-SEThe Alton IL cooper smelter is too close to be indicated by the back trajectories.

Coal combustion

5.74OH River, WV, OH, IN, KY, TN, AR, MS

UniformLocations are consistent with known sources.

Steel production

0.76OH River, N IN, TX, AR-TN-MS, Atlanta

NE-EGranite City Steel is too close to be indicated by the back trajectories.

Nitrate 5.02 Atlanta, OH River and NW NortherlySource location is unknown due to confounding factors.

Crustal 1.43Central MO-AR-N LA-NW TX-W OK

S-SW Most likely from agricultural activities.

Mobile sources

2.92 Distant UniformThe local mobile sources should dominate and are too close to be indicated by the back trajectories.

Summary of Source Apportionment for St. Louis

- 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 - Coal Combustion(Sulfate)

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?).

St Louis - Nitrate

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, TexasSource Number

Preliminary Identification

Notes Key Species and Profile Comments

1 Dirt   Usual crustal elements.

2 FireworksThe 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.

3 Industrial  Key species include Zn, Cl, Cr, Ni, other metals. Other profiles to consider include hogged fuel boiler, industrial average manufacturing.

4Secondary OC/mobile

This site is in a residential neighborhood with freeways to the north.

Key species include OC>EC, NH4, Ca, Mass.

5Marine - Nitrate source

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.

6Mobile/Mn source

The Mn signature may be a result of substituting MDL/2 for Mn.

Key species include Mn.

7Secondary sulfate from fossil fuels

 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.

Source Apportioned mass (g/m3) Back Trajectory

Pollution RoseNotes

Dirt 0.77 Local/Met related S-W  

Fireworks0.49

Local/Met related W-NWThis is essentially a one‑time, local source.

Industrial 0.87 Local/Met related East-South  

Secondary OC/mobile 5.19

Local/Met related Northerly 

Marine‑Nitrate source 0.29

Local/Met related SE and NWThe bi-directionality could be from a sea breeze effect.

Mobile‑Mn source 1.04

Local/Met related SE and NWThe bi-directionality could be from a sea breeze effect.

Secondary sulfate from fossil fuels 5.54

Local/Met related Slightly E-SEThe pollution rose and back trajectories are not consistent.

Summary of Source Apportionment for Houston 

Houston – Secondary Sulfate1. associated with clockwise airflow2. associated with high‑pressure zones rather than an area3. virtually all trajectories enter from the southeast, over the shipping channel4. source contribution function is always lower than would be expected for a

source location 

1. Associated with airflow from the Gulf and airflow out of Canada (red).

2. 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.

3. Source contribution function is very low, which may indicate that the sources are local or, more likely, the relationship is from favorable meteorological conditions.

Houston – Marine Nitrate

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