# Presentation: 389000

## Direct PM2.5 Emissions Data, Testing, and Monitoring Issues

- Ron Myers
- myers.ron@epa.gov
- Measurement Policy Group
- SPPD, OAQPS

## The Issues

- Collecting data needed for effective inventories and SIP development
- Selecting and prescribing appropriate test methods
- Improving monitoring in rules
- Implementing a transition period

## Components of Direct PM2.5

- Filterable PM2.5
- Solid or liquid material at stack temperature and higher (measured at ~250o to 320o F)
- Stable in atmosphere and collected on ambient sampler
- Condensable PM2.5
- Vapor or gas at stack temperature
- Condenses to liquid or solid at stack exit
- Stable in atmosphere and collected on ambient sampler

## Reasons to Consider CondensablePM2.5 Emissions

- Condensable fraction of direct PM2.5 can be significant
- 10 to 50 percent of PM2.5 emissions depending on control measures, temperature, other source-specific conditions
- Combustion, metallurgical & wood product sources emit large quantities of vapors that condense to form PM2.5
- Acids (e.g., sulfuric acid from coal combustion)
- Neutralized acids (e.g., [NH4]2[SO4], NH4Cl )
- Organic materials (e.g., alkanes, PAHs, PCBs, PCDDs, acids)
- Metals (e.g., As, Se, Sb, Pb compounds)
- A small fraction of point sources are responsible for the majority of condensable PM emissions

## Inventories and PM2.5 Emissions

**Filterable PM**
- Historically only PM included in databases
- Some States include filterable PM10 or PM 2.5
**Condensable PM**
- Current knowledge is spotty
- Some SIP databases fail to include PMcond (even when required)
- When PMcond included - calculated from emissions factors (e.g., AP-42) that are often based on incorrect test methods
**Inventories reflect database errors**
- Federal inventory includes some adjustments
- Underestimate some sources’ contributions, overestimate others

## Effect on SIP Regulations

- Most current regulations do not address PMcond
- Focus on filterable PM
- Force control technology towards filterable PM
- Some regulations do include PMcond, but with incorrect test methods
- Final rule creates a transition period
- Regulations addressing PMcond encouraged but not required
- Develop more precise and accurate PMcond emissions for inventories and rules

## EPA Method 202(Condensable PM Test Method)

- Preferred
- N2 purge
- Evaporation @ 80 F
- Neutralize quantitatively by titration

- Optional
- No purge
- Evaporation @ 250 F
- Over neutralize, measure sulfate, assume SO3

- Impact
- 10-20X artifact
- Lose nitrates, chlorides
- Sulfate biased low, SO3 biased high

-   Sample collected in cold water
-   Organic PM extracted with solvent
-   Water & solvent evaporated
-   Residue weighed
-    Procedures

## Test Method Selection is Important for Measuring PMcond

- Variations of Method 202 commonly applied
- Method 202 can be (and often is) conducted incorrectly
- Without N2 purge, dreaded artifacts can form (e.g., SO2 gets trapped in water, reacts with other stuff to form psuedo-PM)
- Artifacts can be > PMcond by orders of magnitude
- Amount of artifact is source-specific and test-specific – variable and unpredictable

## EPA Activities to Resolve PMcond Test Methods Issues

**Recommending use of Method 202 **_**with purge**_** and use of condensable PM****2.5**  (see http://www.epa.gov/ttn/emc/methods/method202.html)
**Assessing “improvements” to Method 202**
- Apply technologies tested in Canada and US
- Reduce artifacts from ~10 mg to >2 mg
**Revise M202 in Appendix M**
- More precise (no options)
- More accurate (reduce artifacts)
- Post on EPA/EMC web site in July 2007
- Propose in 2007/2008
- Promulgate 2008/2009

## EPA PM2.5 Transition Period Activities

**Recommending use of Method 201A (existing filterable PM****10**** test method) with supplemental hardware for filterable PM****2.5**** **
**Revise Method 201A in Appendix M**
- Add filterable PM2.5 measurement
- Available now on EPA/EMC web site as CTM-040
- Propose 2007/2008
- Promulgate 2008/2009
**Encourage stakeholder testing for Total PM****2.5**

## Other EPA Transition Period Activities

**Advance Dilution Sampling Method**
- Promote ASTM Standard development process
- Assess speciation capacity
- Improve consistency mobile source methods
**Document benefits of improved monitoring**
**Develop PM****2.5**** CEMS**
**Develop guidance on understanding and applying data uncertainty**

## April 2008 SIP expectations

- States are encouraged to evaluate and control sources of condensable PM2.5 that may be important in attainment strategies
- However, emissions limits (e.g., RACT, RACM) in 2008 are not required to include condensable PM2.5
- If want credit for condensable PM2.5 reductions, must ensure those reductions with enforceable emission limits

## Your Direct PM2.5 SIP Activities

**By 2011 - transition period**
- Collect information on PM2.5 filterable and condensable
- Include PMcond at your option
- In new rules with appropriate test methods
- As supplemental testing with filterable PM
- Incremental cost ≈$700
- Populate emissions factors database
- Use Electronic Reporting Tool to document emissions tests _[(http://](http://www.epa.gov/ttn/chief/ert/ert_tool.html)__[www.epa.gov/ttn/chief/ert/ert_tool.html](http://www.epa.gov/ttn/chief/ert/ert_tool.html)_ )

## Your Direct PM2.5 SIP Activities

**Post 2011**
- Use information obtained during transition period
- Improve direct PM2.5 emissions inventory
- Revise control strategies
- Revise or establish new PM2.5 limits
- Not necessary to REVISIT old limits
- Must incorporate condensable PM in **NEW** limits
- e.g. SIPs to make mid-course corrections
- SIPs for 2006 PM2.5 standards
- Improve monitoring methods
- Improve management of short term emissions
- Start up/shut down/malfunction
- Continuous performance assessment

## Important Monitoring Elements

- Indicator of performance
- Emission measurements
- Operating parameters
- Work practice
- Raw material or fuel content
- Monitoring technique
- Continuous emissions monitor
- High Sensitivity PM monitor
- Continuous opacity monitor
- Continuous parametric monitoring
- Monitoring frequency
- Averaging time

## Summary - Direct PM2.5 Emissions Issues

- Both filterable and condensable PM2,5 are important components direct PM2.5
- Databases must address both for all sources to ensure effective control program
- Target significant sources
- Establish technologically correct regulations
- Test methods and monitoring must correspond with emissions limitations
- You get what you measure