# Presentation: 583604

## Philip M. Fine, Ph.D.
South Coast AQMD

National Air Quality Conference
April 8, 2008

- Philip M. Fine, Ph.D.
- South Coast AQMD
- National Air Quality Conference
- April 8, 2008

- Overview of Results from the Multiple Air Toxics Exposure Study – III(MATES-III)

## Authors/Contributors

**Jean Ospital, Tom Chico, Joe Cassmassi**, Tuyet-le Pham, Aaron Katzenstein, Bong-Mann Kim, Philip Fine, Sumner Wilson, Rudy Eden, Libby Ayers, Dale Barber, Steven Barbosa, Tracy Basler, Rene Bermudez, Roger Bond, Malou Cartwright, Wimol Chanjamsri, Paul Chavez, Alice Chen, Corie Choa, Amy Chun, Kris Collins, Monique Davis, Alicia Diaz, Jorge Diez, Lila Enriquez, Jeremy Graham, Tracy Goss, Sam Guo, Refaat Hanna, Sheri Hanizavareh, Sandra Hom, Dan Houghton, Tai-Ching Hu, Judy Hwa, Eddie Hwang, Laura Julius, Cindy Kirkpatrick, Mike Koch, Sally Kou, Jong Hoon Lee, Kay Liu, Eddie Lui, Jason Low, Joe Macias, Ricardo Morales, Richard Parent, Tom Parsons, Ed Ruffino, Ken Sanchez, David Sawyer, Mike Shu, Steve Taw, Solomon Teffera, Lyovit Usares, Brian Vlasich, Thy Vo, Jill Whynot, Paul Williamson, Sumner Wilson, Robert Yi, Xinqiu Zhang

## Background

- Multiple Air Toxics Exposure Study (MATES I): 1987
- MATES II: 1998-99
- MATES III: 2004-2006
- SCAQMD Environmental Justice Initiatives
- Focus on toxics exposure and risk
- PM mortality not included

## Key Components

- Monitoring
- Emissions inventory
- Modeling
- Technical Advisory Group input on study plan and draft report

## Enhancements to MATES III

- Monitoring done every 3 days
- Data collected over 2 years: April ‘04 – March ‘06
- Added PM2.5 samples
- Added naphthalene, PAHs, PM organic tracers
- Updated method (CMB) to estimate diesel PM
- Latest 2007 AQMP inventory used
- Improved spatial allocation of truck emissions
- Updated modeling platform consistent with AQMP

## Statistics

- ~18,000 samples collected
- ~37,000 analyses performed
- ~911,000 data points produced

## MATES III Monitoring Sites

## Benzene

## Perchloroethylene

## Methylene Chloride

## Methylene Chloride

## Hexavalent Chromium

## PAHs

## Elemental Carbon - PM10

** ****10 % reduction attributable to new analytical instruments**
** ****Net reduction of 28 %**

- Elemental Carbon - PM10

## Elemental Carbon – PM2.5

## Slide 16

## MATES III Monitoring 

- General trend is down for air toxics levels
- Estimated basin wide lifetime risk 1,200 per million
- Mobile source toxics account for 94% of risk
- Diesel accounts for 84% of air toxics risk
- Non-diesel risk lower by 50%

## Air Toxics Cancer Risk by Site

## Comparison of Diesel PM Estimation Methods

| Estimation Method
 | MATES IIIDiesel PM ug/m3
 | Average Basin Wide Air Toxics Cancer Risk (per million) |
| --- | --- | --- |
| MATES II Method:PM10 EC x 1.04 | 2.16 | 851 |
| 2005 Inventory Method:PM2.5 EC x 1.72 | 3.1 | 1133 |
| CMB Method | 3.20 – 3.49 | 1194 |

## Chemical Mass Balance (CMB) Model

- Used monthly-averaged ambient data with speciated particulate organics
- EPA CMB version 8.2
- Estimate source contributions to ambient concentrations of PM2.5 mass
- Widely used in scientific community
- Suggested by Technical Advisory Group

## PM2.5 Chemical Analysis

- Elemental Carbon (EC)
- Organic Carbon (OC)
- Ionic species (NO3-, SO42-, NH4+, Na+, Cl-)
- Metals (Al, Si, Fe, etc.)
- Organic compounds (75)
- Analyses conducted by DRI
- PAHs (coronene, indeno [1,2,3-cd]pyrene, benzo(ghi)perylene, etc.)
- Hopanes, steranes (sterane 48, hopane 17, etc.)
- Alkanes (phytane, docosane, etc.)
- Polars (guaiacols, syringols, levoglucosan, cholesterol, organic acids, etc.)

## PM2.5 Source Contribution Estimates SoCAB Gasoline Profile: Years 1&2

## MATES III Emissions Inventory

- Estimated emissions of toxics for 2005
- Mobile sources dominate air toxics emissions
- Account for 93% of potency weighted emissions
- Diesel PM contributes 87% of potency weighted emissions of carcinogens
- Using updated methodology to back cast to 1998 - emissions show a decrease in potency  weighted toxics emissions of 15%

## Carcinogenic Emissions(MATES-II vs. MATES-III)

| Source Category | Percent Change |
| --- | --- |
| On-road | 13% decrease |
| Off-road | 1% increase |
| Point | 65% decrease |
| Area | 43% decrease |

## MATES III Modeling

- Updated emissions and modeling
- CAMx - consistent with AQMP
- AQMP inventory updated for toxics
- Improved geographical assignment of diesel vehicle miles – Caltrans/SCAG model
- Updated meteorology for 2005 consistent with AQMP
- EMFAC2007 vs EMFAC7G
- Larger modeling domain
- Grid cell with highest risk at the ports
- Area of increased risk near Central L.A.
- Estimated risks consistent with monitoring data

## MATES II Model Estimated Risk

## MATES III Model Estimated Risk 

## Modeled Risk Comparison

- Population weighted risk: 810/million
- 17% below MATES II
- Emission inventory updates
- Meteorology inputs
- Modeling methodology

## Next Steps

- 90 day public review recently closed
- Draft report and technical appendices available on AQMD web site
- Technical Advisory Group review
- Public outreach ongoing
- Final report
- Air Toxic Control Plan update: Summer 2008