Direct PM2'5 Emissions Data, Testing, and Monitoring Issues

1
Direct PM2.5 Emissions Data, Testing, and
Monitoring Issues

• Ron Myers
• myers.ron_at_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., NH42SO4, 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
EPA Method 202(Condensable PM Test Method)

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

• Preferred
• N2 purge
• Evaporation _at_ 80 F
• Neutralize quantitatively by titration

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

• Optional
• No purge
• Evaporation _at_ 250 F
• Over neutralize, measure sulfate, assume SO3

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 gt 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 gt2 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