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Ambient Air Monitoring for the Revised Lead NAAQS

Ambient Air Monitoring for the Revised Lead NAAQS. Daniel Garver US EPA Region 4. Overview. On October 15, 2008, EPA strengthened the national ambient air quality standards (NAAQS) for lead (Pb). Since 1978, lead standards have been set at 1.5 μ g/m 3

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Ambient Air Monitoring for the Revised Lead NAAQS

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  1. Ambient Air Monitoring for the Revised Lead NAAQS Daniel Garver US EPA Region 4

  2. Overview • On October 15, 2008, EPA strengthened the national ambient air quality standards (NAAQS) for lead (Pb). • Since 1978, lead standards have been set at 1.5 μg/m3 • Now,EPA is strengthening the lead standards by 90 percent to a level of 0.15 μg/m3. • The level is based on the concentration of lead in total suspended particles (TSP) • EPA is also making changes to the lead monitoring network to ensure monitors are assessing air quality in areas that might violate the new standard.

  3. NAAQS Averaging Time and Form: Old vs. New NAAQS • Both specified as “not be exceeded” maximum 3-month average • Both require 1 in 6 day sampling frequency • Old NAAQS based on calendar quarters; new NAAQS based on “rolling” 3-month averages • Also, the 3-month averages (for Old versus New) are calculated slightly different • Data handling details in 40 CFR 50 Appendix R • NAAQS evaluation period handled differently • Old NAAQS had 1-year “look” for designations and 2-year evaluation period for redesignations • New NAAQS will use 3-year look for original designations and also redesignations

  4. NAAQS Averaging TimeOld vs. New

  5. Lead Monitoring Requirements • Lead monitoring required: • At sources emitting 1.0 tpy or more of Pb based on NEI or other justifiable data. • In core-based statistical areas (CBSAs) with population over 500,000. • Approx. 48 total required monitors in Region 4 • Approx. 22 source-oriented monitors must be identified in Network Plans and installed by 1/1/2010 • Monitors must be sited for max concentration, taking into account logistics and the potential for population exposure.

  6. MAP

  7. Source-Oriented Monitoring Waivers[40 C.F.R 58 Appendix D 4.5(a)(ii)] • EPA can grant waivers of required source-oriented monitors if State or Local can demonstrate that: • Maximum Pb concentration will not exceed of 50% of the NAAQS (based on historical monitoring data, modeling, or other means). • Modeling info at EPA’s Support Center for Regulatory Atmospheric Modeling (SCRAM) website at epa.gov/scram001 • AERMOD is the preferred model for near-field dispersion • EPA is creating a post-processing program that reads model output and calculates rolling 3-month averages. • Model must demonstrate max concentration < 0.075μg/m3 • Ambient air means outside facility fence line provided that all of facility property is secured from public access

  8. Source-Oriented Monitoring Waivers (cont.)[40 C.F.R 58 Appendix D 4.5(a)(ii)] • Waiver request letters must be submitted with Network Plans due July 1st. • All required sources must have either: • Signed monitoring waiver, or • Pb monitor operating by January 1, 2010.

  9. Ambient Monitoring Methods • Primary indicator is lead in total suspended particles (Pb-TSP), due to evidence that lead particles of all sizes pose health risks. • Pb-PM10 can be used instead of Pb-TSP monitoring if: • Lead is not expected to occur as large particles; and • Lead concentrations are not expected to have three-month averages greater than or equal to 0.1 μg/m3 • If a Pb-PM10 monitor measures to 0.1 μg/m3 or above, then Pb-TSP monitor must be installed within six months • Pb- PM10 measurements greater than the NAAQS violate the standard. • Anticipate that Pb-PM10 can be used at most or all of the population-oriented sites. • Note that Pb-PM10 data is considered surrogate data for Pb-TSP, and cannot be used to demonstrate attainment with the NAAQS.

  10. Pb-TSP Sampling • High-volume TSP (total suspended particulate matter) sampling • 40 CFR Part 50, Appendix B • Federal reference method (FRM) approved in 1983 for collecting TSP • Collects particles up to 25-50 μm • Flow rate of 1600 liters per minute (LPM) resulting in total 24-hour sample volume of ~2400 cubic meters • Typically samples on 8x10-inch glass fiber or quartz filters

  11. Sampling Methods: Pb-PM10 • Low-volume PM10 sampling • Analysis: 40 CFR Part 50, Appendix Q • PM10c Sampler FRM: 40 CFR Part 50, Appendix O • Collects particles less than or equal to 10 micrometers • Low-volume sampling at flow rates of 16.7 LPM resulting in total 24-hour sample volume of ~24 m3 • Any approved FRM/FEM PM10c sampler can be used when coupled with the FRM Pb-PM10 analysis.

  12. Additional Resources • Lead monitoring information and NAAQS Q&A documents: http://www.epa.gov/ttn/amtic/pb-monitoring.html • Regulatory actions related to the Lead NAAQS including text of the final rule: http://epa.gov/air/lead/actions.html • 2005 National Emissions Inventory (NEI) data for lead sources: ftp://ftp.epa.gov/EmisInventory/2005_nei/lead_summaries/

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