Direct PM 2.5 Emissions Data, Testing, and Monitoring Issues

1. Direct PM2.5 Emissions Data, Testing, and Monitoring Issues Ron Myers myers.ron@epa.gov Measurement Policy Group SPPD, OAQPS

2. 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

3. 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

4. Reasons to Consider CondensablePM2.5 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

5. 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

6. 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

7. Preferred N2 purge Evaporation @ 80 F Neutralize quantitatively by titration Optional No purge Evaporation @ 250 F Over neutralize, measure sulfate, assume SO3 EPA Method 202(Condensable PM Test Method) Sample collected in cold water Organic PM extracted with solvent Water & solvent evaporated Residue weighed Procedures • Impact • 10-20X artifact • Lose nitrates, chlorides • Sulfate biased low, SO3 biased high

8. 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

9. EPA Activities to Resolve PMcond Test Methods Issues • Recommending use of Method 202 with purge and use of condensable PM2.5(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

10. EPA PM2.5 Transition Period Activities • Recommending use of Method 201A (existing filterable PM10 test method) with supplemental hardware for filterable PM2.5 • 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 PM2.5

11. 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 PM2.5 CEMS • Develop guidance on understanding and applying data uncertainty

12. 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

13. 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://www.epa.gov/ttn/chief/ert/ert_tool.html )

14. 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

15. 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

16. 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