1 / 24

PM Facts & NAAQS

PM Facts & NAAQS. Recent characterizations (‘current levels’) of PM data PM Staff Paper – Second Draft Particle Pollution Report – First Edition Potential implications of possible changes to PM NAAQS 2/14/2005 Mark Schmidt Air Quality Data Analysis Group/EMAD/OAQPS.

garrison
Download Presentation

PM Facts & NAAQS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PM Facts & NAAQS • Recent characterizations (‘current levels’) of PM data • PM Staff Paper – Second Draft • Particle Pollution Report – First Edition • Potential implications of possible changes to PM NAAQS 2/14/2005 Mark Schmidt Air Quality Data Analysis Group/EMAD/OAQPS

  2. County-level maximum annual mean PM2.5 concentrations, 2001-2003. • Source: PM Staff Paper • Completeness criteria: 12 quarters of 11+ samples • Event-flagged data included

  3. County-level maximum 98th percentile 24-hour average PM2.5 concentrations, 2001-2003. • Source: PM Staff Paper • Completeness criteria: 12 quarters of 11+ samples • Event-flagged data included

  4. Second Draft PM Staff Paper . . .Staff Recommendations onPrimary Standards (cont.) • PM2.5 primary standards should continue to be based on both annual and 24-hour averaging times • Consideration should be given to an annual PM2.5 standard at the current level of 15 µg/m3 together with a revised 24-hour PM2.5 standard in the range of 35 to 25 µg/m3 OR • Consideration should also be given to a revised annual PM2.5 standard, within the range of 14 to 12 µg/m3, together with a revised 24-hour PM2.5 standard in the range of 40 to 35 µg/m3, to provide supplemental protection against episodic localized or seasonal peaks

  5. Estimated number/percentage/population of counties not likely to meet alternative PM2.5standards One possibility: Keep ‘Annual’ at 15, lower ‘Daily’ 98th to 35-25 Another possibility: Lower ‘Annual’ to 14-12 and lower ‘Daily’ 98th to 40-35 • Source: PM Staff Paper • Completeness criteria: 12 quarters of 11+ samples • Event-flagged data excluded

  6. Annual mean PM2.5 concentrations, 2001-2003. Different combinations of lower ‘annual’ and/or lower ‘daily’ NAAQS could affect different areas, but probably northwest.. 98th percentile PM2.5concentrations, 2001-2003. • But, much too early to try to predict: • Years away from implementation • Listed options are just ‘staff’ recommendations • PM2.5 levels continue to go down • Meteorological effects can be significant • Episodic events need to be considered • Source: PM Staff Paper • Completeness criteria: 12 quarters of 11+ samples • Event-flagged data included

  7. PM2.5 Trends Average annual average trend in PM2.5 mass, ammonium sulfate, ammonium nitrate, total carbonaceous mass, and crustal material at IMPROVE sites, 1993-2003. Regional trends in annual average PM2.5 concentrations in the EPA FRM network, 1999-2003. Source: Particle Pollution Report Source: PM Staff Paper • FRM (mostly urban) PM2.5 concentrations have decreased 10% nationally since 1999. • At the rural eastern sites, measured PM2.5 mass decreased about 23 percent from 1993 to 2003. At the rural western sites PM2.5 mass decreased about 21 percent from 1993 to 2003. At the Washington, D.C. site the annual average PM2.5 concentration in 2003 was about 31 percent lower than the value in 1993.

  8. ‘Local’ versus ‘Regional’ Contribution Source: Particle Pollution report

  9. Estimated county-level maximum annual mean PM10-2.5 concentrations, 2001-2003. • Source: PM Staff Paper • Completeness criteria: 4, 8, or 12 quarters of 11+ samples • Event-flagged data included

  10. Estimated county-level max 98th percentile 24-hr PM10-2.5 concentrations, 2001-2003. • Source: PM Staff Paper • Completeness criteria: 4, 8, or 12 quarters of 11+ samples • Event-flagged data included

  11. How are PM10-2.5 concentration levels estimated? • Currently, no FRM for PM10-2.5 • ‘Most’ of the recent OAQPS characterizations (e.g., PM Staff Paper, Chapter 2) have utilized: • Collocated FRM/FEM PM10 and PM2.5 instruments. • Simplistic difference calculation of same-day measurements (after adjusting PM10 to local conditions) • Small amount of ‘direct’ reported PM10-2.5 (Dichotomous) • ‘2001-2003’ outputs actually represent most recent 4-, 8-, or 12 quarters with 11+samples. • 489 sites met completeness goals: 137 with 4 complete quarters, 122 with 8 complete quarters, and 230 with all 12 complete quarters. • For some analyses (e.g., ‘county counts’), an ‘expanded’ db was utilized: • Same as above plus non-collocated (but nearby - up to 5 miles away) FRM/FEM sites. The PM10-2.5 estimate was anchored at the PM10 site. The assumption is that PM2.5 is fairly homogenous, but PM10 is not. [Why ‘expand’ to included non-colo? Many ‘high’ PM10 sites do not have collocated PM2.5 because of disparate monitoring objectives. For PM10 the central objective is ‘highest concentration’; for PM2.5 the main NAAQS objective is ‘population exposure’. Hence, by not including these non-collocated pairs, we would be ignoring many potentially high PM10-2.5 locations.]

  12. PM10-2.5 compared to PM2.5 and PM10 Source: PM Staff Paper Source: PM Staff Paper Source: Particle Pollution report Source: PM Staff Paper

  13. Second Draft PM Staff Paper . . .Staff Recommendations onPrimary Standards (cont.) • Consideration should be given to setting a 24-hour PM10-2.5 standard about as protective as the current daily PM10 standard, with a level in the range of approximately 65 to 75 µg/m3, 98th percentile, or approximately 75 to 85 µg/m3, 99th percentile. • Also some support for consideration of a PM10-2.5 standard down to approximately 30 µg/m3, 98th percentile, or 35 µg/m3, 99th percentile, recognizing that a standard set at such a relatively low level would place a great deal of weight on very limited and uncertain epidemiologic associations

  14. Estimated number/percentage/population of counties not likely to meet alternative PM10-2.5std.’s One possibility: Set ‘Daily’ 98th at 75-30 • Source: PM Staff Paper • Completeness criteria: 4, 8, or 12 quarters of 11+ samples • Event-flagged data excluded

  15. Like, existing PM10 NAAQS, a PM10-2.5 NAAQS would have more pronounced affect on the west • But, many (spread-out) eastern counties could potentially also violate Estimated 98th percentile PM10-2.5concentrations, 2001-2003. • Much too early to try to predict areas: • Years away from implementation • Listed options are just ‘staff’ recommendations • Considerable estimation (measurement) uncertainty? • PM10-2.5 composition may be a factor • Little focus on PM10-2.5 trends until recently • Meteorological effects unpredictable • Episodic events need to be considered

  16. Annual average PM10-2.5 concentration trend at IMPROVE sites, 1993-2003. 9 8 7 6 mg/m3 5 4 3 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 7 Eastern Sites 17 Western Sites Washington, D.C. Site Source: PM Staff Paper • At the rural eastern sites, measured PM10-2.5 in 2003 was about 33 percent lower then the corresponding value in 1993. At the rural western sites, measured PM10-2.5 was about 17 percent higher in 2003 than the corresponding value in 1993. At the Washington, DC site the annual average PM10-2.5 concentration in 2003 was about 25% lower than the 10-year peak in 1994, but nearly 2 Fg/m3 higher than the 1998 low point.

  17. PM10-2.5 (‘coarse’) Amm. Nitrate 0.7% 12.9% 21.0% 5.8% 59.5% Amm. Nitrate Amm. Sulfate Crustal OC EC Average PM10-2.5 (‘coarse’), PM2.5 (‘fine’) and PM0.1 (‘ultrafine’) chemical composition at an EPA ‘supersite’ monitor in Los Angeles, CA, 10/2001 to 9/2002. • Components shown in clockwise order (starting with ammonium nitrate) as listed in legend from top to bottom. • Higher percentage of crustal material in larger size fractions • Higher percentage of carbon in smaller size cuts • At this site, the highest percentage of sulfates and nitrates are in fine segment Sources: Supersite PI; Particle Pollution Report, PM Staff Paper

  18. Episodic events can cause significant short-term increases in PM concentrations PM2.5 PM10-2.5 Hourly PM2.5 and PM10-2.5 concentrations at a El Paso, TX monitoring site, April 26, 2002-April 27, 2002. Source: PM Staff Paper Picture source: Particle Pollution report

  19. How does PM2.5 relates to visibility? • Visual Range = 3912 / • {[(3) * f(RH) * PM2.5 mass of sulfates] + • [(3) * f(RH) * PM2.5 mass of nitrates] + • [(4) * PM2.5 mass of OCM] + • [(10) * PM2.5 mass of EC] + • [(1) * PM2.5 mass of ‘soil’ or ‘crustal’] + • [(0.6) * PM10-2.5 mass] + • 10 (Rayleigh scattering by gases)} • Where ……. • Visual Range is in units of kilometers • PM2.5 component masses are in units of µg/m3. • f(RH) is a relative humidity factor that accounts for the relative humidity effects on hygroscopic aerosols; see look-up table to right {Bracketed denominator} also known as Reconstructed Light Extinction (RE), in units of inverse megameters (Mm-1)

  20. Relationship between reconstructed light extinction (RE) and 24-hour average PM2.5, 2003. • Reconstructed Extinction (RE) in units of inverse megameters • RE calculated each hour then averaged for the day • Hourly RE computed from a speciated continuous PM2.5 db (TEOM / BAM data multiplied by same-site-day PM2.5 component profiles); PM10-2.5 from collocated continuous PM10 or via regional ratios of ‘fine / course’; and hourly humidity data from the nearest NWS site. RE= [(3) * f(RH) * PM2.5 mass of sulfates] + [(3) * f(RH) * PM2.5 mass of nitrates] + [(4) * PM2.5 mass of OCM] + [(10) * PM2.5 mass of EC] + [(1) * PM2.5 mass of ‘soil’ or ‘crustal’] + [(0.6) * PM10-2.5 mass] + 10 (Rayleigh scattering by gases) East (circles): RE = 7.8 * PM2.5 + 8.5; R2=0.70 West (stars): RE = 6.9 * PM2.5 + 4.1; R2=0.72 All: RE = 7.6 * PM2.5 + 7.9; R2=0.70 Source: PM Staff Paper

  21. Model slope for relationship between reconstructed light extinction (RE) and hourly PM2.5 (increase in RE due to incremental increase in PM2.5), 2003. Why focus on daylight period? • Slope decreases during daylight hours because relative humidity effects are diminished. Hence, slope more closely approximates extinction efficiency of dry PM2.5 • Not only are slopes lower for all regions, but there is more comparability in PM2.5:RE relationship during daytime. Model (RE= PM2.5) Slope Source: PM Staff Paper

  22. Second Draft PM Staff Paper . . .Staff Recommendations onSecondary Standards • Consideration should be given to revising the current secondary PM2.5 standards to provide increased and more targeted protection primarily in urban areas from visibility impairment related to fine particles • Consideration should be given to a 4- to 8-hour PM2.5 standard in the range of 30 to 20 µg/m3 to protect visual air quality primarily in urban areas (generally resulting in a visual range of approximately 25 to 35 km), as well as in surrounding non-urban areas • Consideration should be given to using a percentile-based form for such a standard, focusing on a range at or somewhat above the 90th percentile of the annual distribution of daily short-term PM2.5 concentrations, averaged over 3 years

  23. PM Staff Paper • Posted at: http://www.epa.gov/ttn/naaqs/standards/pm/data/pm_staff_paper_2nddraft.pdf. (Print / CD version available.) • Health and Ecosystems Effects Group (HEEG) of AQSSD/OAQPS • Karen Martin ~ (919) 541-5274 • Mary Ross ~ (919) 541-5170 • Next Steps: • April, 2005 - CASAC meeting to review (2nd draft) Staff Paper • June 30, 2005 - final Staff Paper • December 20, 2005 - Federal Register (FR) proposal • September 27, 2006 - FR final rule

  24. Particle Pollution Report • Posted at http://epa.gov/airtrends/pm.html(Print version soon) • Air Quality Data Analysis Group (AQDAG) of EMAD/OAQPS • Tesh Rao ~ (919) 541-1173 • Neil Frank ~ (919) 541-5560 • Next steps: • EMAD ‘PM-Team’ to focus on priority / policy-relevant issues; e.g., PM2.5 ‘daily‘ levels, PM2.5 attainment progress, PM10-2.5 speciation, episodic events • Next report ~ Fall ‘05

More Related