Ambient Air Monitoring for the Revised Lead NAAQS Daniel Garver US EPA Region 4.
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Transcript of 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
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.
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
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.
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
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.
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.
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
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.
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/