# Presentation: 616408

## The Chemical Composition of PM2.5To Support PM2.5 Implementation

- Neil Frank
- AQAG/AQAD  OAQPS/USEPA
- For Presentation at
- EPA State / Local / Tribal Training Workshop: PM 2.5 Final Rule Implementation and 2006 PM 2.5 Designation Process
- June20-21,2007

## Topics

- How do we derive FRM PM2.5 composition
- How does avg composition vary by region,  by season and over time
- Variation within urban areas
- What are the local vs regional components and how does this relate to potential emission sources
- Differences between peak day and average composition

## What is the composition of PM2.5 and where does it come from?

- _Major components_
- Ammonium Sulfate
- Ammonium Nitrate
- Organic Carbonaceous Mass
- Elemental Carbon
- Crustal Material

- SO2

- NOX

- Direct PM
- & VOC

- +NH3

- The chemistry is complicated and particle formation
- is dependent on other pollutants and atmospheric conditions

**From: *****The Particle Pollution Report: ***
***Current Understanding of Air Quality and Emissions through 2003***

## To estimate urban PM2.5 composition

- Use measurements from routine speciation monitoring networks
- Make adjustments to represent mass as measured by Federal Reference Method monitor
- The FRM defines the regulatory _indicator_ of PM2.5.
- FRM mass may not retain all volatile nitrate, and includes particle bound water and other components not estimated directly with speciation measurements.
*FRM mass does *_*not*_* equal the simple sum of the measured components*
*[i.e. PM2.5 = AmmSul + AmmNitr + OCM +EC + Crustal]*

## Annual Average Composition (2002-04) in East NA areas

- With FRM adjustment per SANDWICH

-                  Less nitrate and more sulfate mass with SANDWICH

- NA area without STN data (02-04)

- Black outlined pies had collocated FRM and speciation

- NA area: Wheeling, WV-OH                                 15.1

## Annual Average Composition (2002-04) in West NA areas

- RCFM

- SANDWICH

-                   Less nitrate and more carbon mass with SANDWICH

- Black outlined pies have collocated FRM and speciation

##     Quarterly PM2.5 Composition in Eastern NA areas, 2002-04

- Q1

- Q3

- Q2

- Q4

-     Quarterly PM2.5 Composition in Eastern NA areas, 2002-04

*Note: Many areas do not have speciation data and some at a different site*

- No
- speciation
- data in
- 2002-04

##     Quarterly PM2.5 Composition in Western NA areas, 2002-04

- Q1

- Q3

- Q2

- Q4

-     Quarterly PM2.5 Composition in Western NA areas, 2002-04
- 1st and 4th quarters have higher concentrations (except LA)

## Composition Can Vary Within the NA Area“Generally” the extra component is carbon

- Allen Park airs_site_code=261630001 year=2003

-  Dearborn airs_site_code=261630033 year=2003

- More sulfate, carbon and crustal

- For some cities, there are gradients in non-C components

## What to do if speciation is not at the DV site?

- Baltimore (Essex speciation site) is not at DV site, 2002 speciation data

- When DV site does not have speciation data, the unknown mass may or may not be TCM
- It could be crustal material (as we observe in Birmingham and Detroit) or possibly Nitrate

*Accounting for differences in within-area speciation profiles*

- Speciation location (Ann Avg=14.9 ug/m3)

- NA area: Baltimore, MD - 240053001(2002-04)

- Sulfate_mass

- Nitrate_mass

- TCM

- Unknown_at_DV_site

- Crustal

- Passive

- DV site (16.3 ug/m3)

- 1.4 ug/m3 is unknown

## Regional Trends in PM2.5 Composition, 2002-2006

*Compositional changes in some regions*

- Lower nitrates
- and sulfates.
- Increasing Carbon

- Reduced Nitrates,
- Sulfates & Carbon

- No change Sulfates.
- Decreasing Nitrates
- Increasing Carbon

- Lower nitrates
- and sulfates

- Lower nitrates
- and sulfates

- Lower nitrates
- and sulfates

- 02   03   04   05  06

- 02   03   04   05  06

- 02   03   04   05  06

- 02   03   04   05  06

- 02   03   04   05  06

- 02   03   04   05  06

*DRAFT*

- Gray line represents the difference between SANDWICH OCM and measured OC estimated with blank correction and 1.4 multiplier

## SANDWICH data are now available on Air Explorer

- _[http://](http://www.epa.gov/airexplorer/)__[www.epa.gov/airexplorer](http://www.epa.gov/airexplorer/)__[/](http://www.epa.gov/airexplorer/)_

## The Urban Excess

## Urban PM2.5 is Composed of Urban and Regional Components

- Urban Composition,
- PM2.5 ~17ug/m3

- +

- Urban Increment
- ~6ug/m3

- Regional Contribution
- ~11ug/m3

- 36%

- 26%

- 54%

- 47%

- 10%

- 33%

- 12%

- 21%

- 17%

- 5%

- 11%

- 16%

- Baltimore PM2.5 compared to
- Upwind rural site illustrates urban/rural contributions

- Based on constructed mass (not SANDWICH), *March 01 – Feb 02*

## Urban PM2.5 is Composed of Urban and Regional Components

*From Particle Pollution Report, 2003*
*Comparing single urban and rural locations*

- _Sulfates_
- Most from regional sources

- _Carbon_
-  Large PM2.5 component
-  Local contribution (40-70%)

- _Nitrates_
-  10-30% of PM2.5
-  Some east avg. ambient nitrates
-    ~4 ug/m3
-  Local contribution _>_ 50%

- Based on reconstructed mass (not SANDWICH), *2003*

## Carbon and Nitrates dominate the average local urban excess 

- Composition of Eastern PM2.5 Non-Attainment Areas

- Estimated PM2.5 Composition

- Estimated Urban Excess

- * Indicates areas with > 30% UE nitrates

- Based on constructed mass (not SANDWICH), *2003*

## High Day vs. Average Composition

*Average Concentration is based on all days but is strongly influenced by the highest concentration days*

## Composition on Annual  Average and High PM2.5 Days Some source categories and regional influences may be more important for high concentration days

- Comparing average of 5 highest days during 2003, regional sources of sulfates and nitrates are larger contributors to peak day concentrations than to annual average (selected city analysis)
- Composition can vary from high day to high day
- Carbon can be smaller as %  -- but  still larger in absolute concentration values --  compared to the average

- S

- MW

- CA

- NE

*From PM Staff Paper (Rao et al)*

- Birm
- Atlanta
- NYC
- Cleveland
- Chicago
- St .Louis
- SLC
- Fresno

- UT

- More Sulfate

- More Nitrate

- High PM2.5 _days have_:

- This analysis shows
- PM2.5 Composition of the ambient aerosol
- (_not_ adjusted to represent FRM mass)

## Percent of 2003-05 FRM Days > 35 ug/m3 by Month Based on all sites which violate 24-hr NAAQS

_**% **_**50**
**  **
**25**
**0**

- NW

- UT

- IMW

- Mid CA

- S.CA

- SE

- MidAtl

**Percent of 2003-05 FRM Days > 35 ug/m3 by Month **Based on all sites which violate 24-hr NAAQS

- J  F  M  A  M  J  J  A  S  O  N  D

-     J  F  M  A  M  J  J  A  S  O  N  D

- J  F  M  A  M  J  J  A  S  O  N  D

- La Cruces, NM

_**% **_**50**
**  **
**25**
**0**

- J  F  M  A  M  J  J  A  S  O  N  D

##  “Example” Composition for High Days [“Warm” Season (May-Sept) & “Cold”]

- NW

- UT

- IMW

- Mid CA

- S.CA

- La Cruces
- NM

- SE

- MidAtl

** “****Example” Composition for High Days **[“Warm” Season (May-Sept) &** ****“**Cold”]
- But sites can be different within each “domain”

- Cold

- Cold        Warm

- Cold        Warm

- Warm

- Cold        Warm

- Cold

- Cold

- Cold

- El Paso STN

**or**

-     J  F  M  A  M  J  J  A  S  O  N  D

- J  F  M  A  M  J  J  A  S  O  N  D

_**% **_**50**
**  **
**25**
**0**

_**% **_**50**
**  **
**25**
**0**

**Pies represent average of 3 highest days per year per season, using SANDWICH**

**or**

## Potential Source Influences by Season and Scale

| Season & Affected 
Domains | 
Major PM2.5 Components |  | 

Source category | Typical Scales of Influence |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  |  |  |  | Regional | Urban | Micro |
| Cold
 IMW
 Mid-Atl
 S. CA
 UT
 Mid CA
 NM
 AK | 
Nitrate |  | EGU (NOx)
Ag (NH3)
Mobile (NOx+NH3) | 

 | *
*
 | 

 |
|  | Sulfate |  | EGU (SO2) |  | * |  |
|  | Carbon |  | Mobile, Area/RWC, Industry |  |  |  |
|  | Crustal |  | Industry, Mobile |  |  |  |
| Warm
 IMW
 Mid-Atl
 SE
 S. CA | Sulfate |  | EGU (SO2) |  | * |  |
|  | Carbon |  | Mobile, Area, Industry, Biogenics and Smoke |  |  |  |
|  | Crustal |  | Mobile, Area, Industry |  | * |  |

- Underlined text indicates dominant season for the domain     Carbon includes OC and EC   ** *******Sometimes occurs

## Appendix A.  

- More on SANDWICH
- and Comparisons with RCFM

## FRM doesn’t retain all ambient nitrates

- Monthly and Annual Average NO3, 2003

- STN (total bar)

- FRM (red bar
- and black line)

- Reconstructed Fine Mass
- RCFM
- (reflects ambient)

- SANDWICH
- (reflects FRM PM2.5)

- FRM Compared to Speciation
- _Network Measurements_
-  Less Nitrate
-  Includes particle bound water
-  Carbon achieves mass balance
-  and reflects all needed adjustments

- PM2.5 mass _also_ includes
- particle bound water
- (at mass weighing conditions)

## SANDWICH more than a cute acronym

- What is the **SANDWICH** Approach?
**S**ulfate, **A**djusted **N**itrate, **D**erived **W**ater, **I**nferred **C**arbon **H**ybrid material balance approach
- for estimating PM2.5 mass composition as if it was measured by the PM2.5 FRM.
- The approach uses a combination of speciation measurements and modeled speciation estimates to represent FRM PM2.5.
- Why is it needed?
- The FRM defines the regulatory _indicator_ of PM2.5.
- FRM mass may not retain all nitrate, and includes particle bound water and other components not estimated directly with STN measurements.
- To estimate FRM PM2.5 composition including FRM carbonaceous mass _without_ “fudge” factors.
- To help QC speciation measurements
- SANDWICH is the default method in EPA modeling guidance to define baseline PM2.5
-  for SMAT (_s_peciated _m_odeled _a_ttainment _t_est)
- “FRM” composition with the p*eer-reviewed “SANDWICH” technique used in CAIR and PM**2.5** RIA*

- Frank, N.   Retained Nitrate, Hydrated Sulfates, and Carbonaceous Mass
- in Federal Reference Method Fine Particulate Matter for Six Eastern U.S. Cities,
-  *J. Air & Waste Manage. Assoc. ***56** :500–511

## Conceptual Overview of Mass Balance Approaches

- (a) W. Reduced Nitrates

- (b) With added water

- (c) Plus filter contamination
-      (= FRM “blank”)

- (d) Remaining unknown mass
- is assigned to carbon

- Approach
- using measurements
- and calculated values

- *

- Distribute
- unknown
- (or scale all down) equally

- *  Default SANDWICH can be modified to consider
-  other components, like salt. This reduces estimate of TCM.

- (2) _SANDWICH_

*Sulfate mass increases*

## FRM composition can be very different than constructed mass from speciation measurements

-                       **PM2.5 and Components, ug/m3**
-           **0                                                                              60**

- Rubidoux, CA (2005)

- RCFM

- SANDWICH

- FRM PM2.5 mass

- Less nitrate mass
- More sulfate and carbon

- Over-estimates FRM mass

***FRM composition can be very different than constructed mass from speciation measurements***

## FRM composition can be very different than constructed mass from speciation measurements

- RCFM

- SANDWICH

- FRM PM2.5 mass

-                       **PM2.5 and Components, ug/m3**
-           **0                                                                              60**

- Less nitrate mass
- More sulfate and carbon

- Birmingham, AL (2005)

- Under-estimates FRM mass

- Birmingham,AL   site=  010732003  (2005)

***FRM composition can be very different than constructed mass from speciation measurements***

## Appendix B.  

- More on Annual Average and
- High Day Composition by Season,
- 2003-05.

## Industrial Midwest

- J  F  M  A  M  J  J  A  S  O  N  D

- _Industrial Midwest_
-  Generally nitrate dominated winter-time values
-    in northern areas
-  Sulfate dominated episodes in summer (region-wide)

- Note: Passive is PM2.5 unrelated to emissions

- IMW

- Northern Site (Grand Rapids, MI)

- Ann                        _Avg of top 3 days/yr_

- Avg                        Cold                      Warm

- Number inside pie is the “top 3” average concentration, ug/m3

- 43
- ug/m3

- 38
- ug/m3

- 38
- ug/m3

- 24hr DV= 37 ug/m3

- 24hr DV= 38 ug/m3

- More Details about PM2.5
- Chemical Composition for the IMW

- 13.1
- ug/m3

- Southern Site (Indianapolis, IN )

- 15.4
- ug/m3

- 37
- ug/m3

## Milwaukee, WI        

- Milwaukee, WI

- Grand Rapids, MI

- Detroit (Dearborn), MI

- Detr (Allen Park), MI

- Buffalo, NY

- Charleston, WV

- Indianapolis, IN

- Elkhart, IN

- Pittsburgh, PA

- Liberty, PA

- Note: Map show existing NA areas
-           & new violation sites

**Nitrates -  important in the N. sub-Region**
**Sulfates and warm season in S. portion**

- 24hr DV= 44ug/m3

- 24hr DV= 40ug/m3

## Mid_Atlantic Region

-     J  F  M  A  M  J  J  A  S  O  N  D

- _Mid_Atlantic Region_
- Generally Sulfate dominated episodes
- everywhere in summer
- Fewer Nitrate contributed winter-time values
- (except in SE. PA)

- MidAtl

- Western Mid-Atl site: State College, PA

- Eastern Mid-Atl site: Wilmington, DE

- 33

- 42

- 36

- 24hr DV= 37 ug/m3

- 24hr DV= 37 ug/m3

- 32

## Lancaster, PA        

- Lancaster, PA

- Philadelphia, PA

- Elizabeth, NJ

- New York, NY

- Wilmington, DE

- Washington, DC

- State College, PA

**Sulfates dominate high Summer days**
**Nitrates -  important  on fewer cold days**

## SE

-     J  F  M  A  M  J  J  A  S  O  N  D

- Insufficient
- Data for
- Ann Avg

- _South East Region_
- Mostly sulfate dominated + OC episodes, in summer
- 	-- shows influence of biogenics and other SOA
- Fewer cold-season exceedances (& are driven by carbon)

- Existing NA: Birmingham, AL

- New 24hr Violation: Phenix City, AL
-                        (Columbus, GA area)

- 34

- 40

- 39

- 24hr DV= 39 ug/m3

- 24hr DV= 37 ug/m3

- 32

## Birmingham, AL

- Rome, GA

- Hickory, NC

- Phenix City, AL (Columbus, GA area)

**Sulfates and carbon during summer**
**Carbon more important on fewer cold days**

-  Note:  Columbus area designated Attainment in 2005 on basis of spatial averaging.

## Southwestern US 

- _Southwestern US _
- Speciation data (from El Paso) suggest emission sources creating crustal and carbon
- Shows effect of aridity and wind

- 24hr DV=42 (not pop- oriented?)
- Ann DV=17.3

- Las Cruces,
- NM
- 24hr DV=36
- Ann DV=10.4

*Nitrate data was not available for this site*

- Insufficient
- Data for
- Ann Avg

- No summer
- days
- > 30 ug/m3

- Las Cruces, NM

- El Paso, TX

## S.CA

- _Southern California_
-  Nitrates dominate High PM2.5 in LA.
-  Carbon (summer) and also nitrates (winter) in Calexico
-   Lower  % crustal on high days

- Downwind of LA: Rubidoux, CA

- Border Site: Calexico, CA

- 70

- 45

- 34

- 24hr DV= 65 ug/m3

- 24hr DV= 39 ug/m3

- 32

## Los Angeles, CA

- Rubidoux, CA

- Calexico, CA

**Composition Varies Across this Diverse CA Domain**

- 24hr DV= 56 ug/m3

- 24hr DV= 65 ug/m3

## Mid CA

-     J  F  M  A  M  J  J  A  S  O  N  D

- _Middle California_
-  Carbon in Northern Central Valley
- from RWC?
-  Nitrates dominate High PM2.5 in lower SJV

- No warm
- season exceedances

- No warm
- season exceedances

- Northern Central Valley (e.g. Sacramento)

- Southern SJV (e.g. Bakersfield, CA)

- 41

- 24hr DV= 45 ug/m3

- 24hr DV= 58 ug/m3

- 61

## Chico, CA

- Sacramento, CA

- Modesto, CA

- Fresno, CA

- Bakersfield, CA

- San Jose, CA

**Nitrates dominate peak days in Southern SJV**
**Carbon is big contributor in N. Central Valley (RWC)**

## NW

-     J  F  M  A  M  J  J  A  S  O  N  D

- _North West_
-  Carbon dominates Libby (from RWC?)
-  Nitrates are also found on high winter days in Missoula (and elsewhere, e.g. Boise)
- -- mobile and valley influence  or ?
-   Summer days are flagged fires
-  (not concurred?)

- No warm
- season exceedances

- Missoula, MT (traffic influenced)

- Libby, MT (RWC)

- 51

- 24hr DV= 41 ug/m3

- 24hr DV= 44 ug/m3

- 42

## Difficult to predict composition from nearby locations

- (e.g. Missoula composition is similar to Boise
-         but different than Libby)

- Libby, MT

- Missoula, MT

- New violation locations without STN data

**Composition Varies. Only Carbon at some locations.**
**Nitrate is evident at other sites. Many Viol sites wo STN**

- Topography
- Effects?

## UT

- _High PM2.5 in Utah_
-  Consistently more Nitrates on high days
-  SLC has similar % Sulfates as ann avg
-  Lindon – one summer exceedance
-  unflagged fire?

- No warm
- season exceedances

- Salt Lake City, UT

- Lindon, UT

- 52

- 24hr DV= 47 ug/m3

- 24hr DV= 43 ug/m3

- 53

- Prescribed
- Fire

## Bountiful, UT

- SLC, UT

- Lindon, UT

**Many Violating Locations in UT**
**Nitrates seems to dominate peaks**

- Logan (Cache Co.)
- Ogden (Weber Co)
- Bountiful (Davis Co).
- SLC
- Lindon
- Provo
- Spanish Fork City

- Ogden-Clearfield
- CBSA

- Provo-Orem
- CBSA

## Alaska

- _High PM2.5 in Alaska (Fairbanks)_
-   50% carbon on winter exceedance day
-   Two summer exceedances are flagged fires (not concurred)

- Insufficient
- Data to
- Compute
- Ann. avg

- 33

- 33

- 24hr DV= 40 ug/m3

- 33