Montana SIP Approval (Partial)

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EPA is partially approving and partially disapproving State Implementation Plan (SIP) revisions submitted by the State of Montana on August 26, 1999, May 28, 2003, March 9, 2004, October 25, 2005, and October 16, 2006. The revisions contain new, amended, and repealed rules in Subchapter 7 (Permit, Construction, and Operation of Air Contaminant Sources) that pertain to the issuance of Montana air quality permits, in addition to other minor administrative changes to other subchapters of the Administrative Rules of Montana (ARM).

See FR notice here.
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Coal Combustion Residue (CCR) Regulation Status Update

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These outlines were made available as part of an audio presentation through Law Seminars that Grant and I participated in. A few highlights of the presentation:

• It is fairly certain that EPA will not issue a final rule this year. There is speculation that a final rule won't be released before next year's elections and EPA is considering requesting further public input.
• The House Energy and Commerce Committee is currently considering a bill that would short circuit EPA's efforts, prohibit any rule listing CCR as hazardous waste, and allow states to regulate the material. Here's a recent news article about the bill. 
• There is a great deal of pressure for legislative intervention because the power and CCR industries don't feel a hazardous designation would be at all workable, because the pervasive and apparently unending uncertainty is causing significant problems with planning for current and future disposition of CCR, and because the utilities are faced with an onslaught of new environmental regulations that could result in requirements for large capital expenditures.
• One of the presenters noted that those pushing for hazardous regulation are largely environmental groups opposed to coal-fired power and industries that compete with CCR for its various beneficial uses. On the other hand -- according to him -- there is overwhelming opposition to a hazardous waste determination.
• It was noted that the technical disposal requirements between the two options (RCRA Subtitle C, hazardous, or D, nonhazardous) are slight. The main reason EPA favors the Subtitle C option is that they would be responsible for enforcement rather than the states--not the case for the Subtitle D option and current regulation.

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Indian Country Minor and Non-Attainment NSR

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June 13, 2011 - EPA finalized a Federal Implementation Plan (FIP) to ensure that Clean Air Act permitting requirements are applied consistently to facilities in Indian country.

Find the final rule and fact sheet here.

Update 7/21/11---

EPA distributed this PowerPoint presentation they plan to follow for a 8/2/11 webinar on the new rule. I briefly reviewed it and observed the following:

• BACT is required.

• The timeline for a synthetic minor permit is 60 days for a completeness determination plus one year to issue the permit.
• Timeline for a true minor source seeking a general permit: 45 day completeness review; permit "90 days after date coverage request is submitted."
• General permits "not allowed for synthetic minor sources."
• Leaves a lot of discretion regarding modeling demonstrations. They plan to develop guidelines.
• 18 months to commence construction.
• 30-day appeal period; permit stayed upon appeal.
• Pollutant-specific deminimis emission levels.
• Existing synthetic minor sources (minor relying on the Transition Policy) must submit an application by 8/30/2012.

• Violations enforceable by EPA in Federal court.

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Proposed Utility MACT

Link to EPA site with proposed rule, fact sheets, and presentation (click on title).

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Updated NO2/SO2 1-hr modeling guidance

EPA released additional guidance for modeling 1-hour NO2 NAAQS compliance 3/1/2011. It updates OLM and PVMRM policy, addresses significant contribution analyses using the SILs, and discusses how to perform cumulative analyses including the option of incorporating temporally-varying background concentrations.

It also "[r]ecommends that compliance demonstrations for the 1-hour NO2 NAAQS address emission scenarios that can logically be assumed to be relatively continuous or which occur frequently enough to contribute significantly to the annual distribution of daily maximum 1-hour concentrations based on existing modeling guidelines, which provide sufficient discretion for reviewing authorities to not include intermittent emissions from emergency generators or startup/shutdown operations from compliance demonstrations for the 1-hour NO2 standard under appropriate circumstances."

3/1/2011 Policy Memo

See this blog post for access to previous memos.

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See this article for a helpful discussion of the state of SO2 and NO2 1-hr NAAQS modeling guidance, including April updates to AERMOD and AERMET. It also talks about recent EPA guidance to states for 1-hr SO2 NAAQS attainment designation.
(added 5/20/2011, KMM)
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Boilers NESHAPs, Final 2/21/2011

UPDATE: On May 18, EPA suspended for reconsideration the major source boiler MACT (Subpart D5) and the CISWI Rule. No date was given for completion of the review.) (KMM 6/27/11) 

Go to this EPA web site for a compilation of actions related to the boiler MACTs and the CISWI rule.


Finalized NESHAP for:

• Area Source Industrial, Commercial, and Institutional Boilers (JJJJJJ)
• Major  Source Industrial, Commercial, and Institutional Boilers and Process Heaters (DDDDD)

Also finalized NSPS for Commercial/Industrial Solid Waste Incinerator Units (Subpart CCCC; Subpart DDDD provides emissions guidelines and compliance times for CISWI units).

Here's an article analyzing the rules and related issues.

Here are some applicability and requirements flow charts that Joe and Rebecca (and ??) prepared (click on links to pull up each chart):

• Biomass
• Coal
• Oil

See 5/5/2010 post for background on proposed rule.

(title is link to EPA site with rules and fact sheets)

Oil and Gas Enviornmental Implications -- R8 EPA 2008 Report

EPA's view of air, water, and solid waste impacts from the industry and discussions of federal, state, and regional efforts to reduce impacts. Billed as a working draft.

An Assessment of the Environmental Implications of Oil and Gas Production: A Regional Case Study

Tailoring Rule Guidance, November 2010

GHG PSD and Title V Guidance

Regarding biogenic emissions sources, EPA indicates that it's still unsure of how to account for them and plans to issue further guidance next year. It's interesting how they think May of 2011 is "well before the start of the second phase of PSD implementation pursuant to the Tailoring Rule"; heck, that could give someone one or two whole months to respond! Here's a relevant section from the document:

“…numerous stakeholders requested that EPA exclude, either partially or wholly, emissions of GHG from bioenergy and other biogenic sources for the purposes of the BACT analysis and the PSD program based on the view that the biomass used to produce bioenergy feedstocks can also be a carbon sink and therefore management of that biomass can play a role in reducing GHGs. EPA plans to provide further guidance on the [sic] how to consider the unique GHG attributes of biomass as fuel.

“Even before EPA takes further action, however, permitting authorities may consider, when carrying out their BACT analyses for GHG, the environmental, energy and economic benefits that may accrue from the use of certain types of biomass and other biogenic sources (e.g., biogas from landfills) for energy generation, consistent with existing air quality standards. In particular, a variety of federal and state policies have recognized that some types of biomass can be part of a national strategy to reduce dependence on fossil fuels and to reduce emissions of GHGs. Federal and state policies, along with a number of state and regional efforts, are currently under way to foster the expansion of renewable resources and promote biomass as a way of addressing climate change and enhancing forest-management. EPA believes that it is appropriate for permitting authorities to account for both existing federal and state policies and their underlying objectives in evaluating the environmental, energy and economic benefits of biomass fuel. Based on these considerations, permitting authorities might determine that, with respect to the biomass component of a facility’s fuel stream, certain types of biomass by themselves are BACT for GHGs. To assist permitting authorities further in considering these factors, as well as to provide a measure of national consistency and certainty, EPA intends to issue guidance in January 2011 that will provide a suggested framework for undertaking an analysis of the environmental, energy and economic benefits of biomass in Step 4 of the top-down BACT process, that, as a result, may enable permitting authorities to simplify and streamline BACT determinations with respect to certain types of biomass.

“… Finally, EPA also plans to determine by May 2011, well before the start of the second phase of PSD implementation pursuant to the Tailoring Rule, whether the issuance of a supplemental rule is appropriate to address whether the Clean Air Act would allow the Agency and permitting authorities or permitted sources, when determining the applicability of PSD permitting requirements to sources of biogenic emissions, to quantify carbon emissions from bioenergy or biogenic sources by applying separate accounting rules for different types of feedstocks that reflect the net impact of their carbon emissions.” pages 9 & 10

Regarding BACT:
Refers to technical “white papers” that provide industry-sector-specific GHG BACT guidance, but it doesn’t say where to find these documents. (page 21)

The guidance explicitly requires consideration of alternate processes that may have better energy efficiency. They offer an example of comparing a supercritical and subcritical coal fired boiler (page 22). The guidance presents a detailed analysis of this issue starting on page 27.
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GHG Reporting, Subpart W, Petroleum and Natural Gas Systems

Final rule published 11/8/10; published in Federal Register 11/30.
Final Rule

Here's an overview article published March 2011 in the Air Pollution Consultant on-line magazine (available through Cyber Regs). (Added 6/14/11, KMM)


All the Part 98 subparts are collected here:
GHG Reporting Rule Web Site

Here's the text relating monitoring and QA/QC requirements (§98.234):

The GHG emissions data for petroleum and natural gas emissions sources must be quality assured as applicable as specified in this section. Offshore petroleum and natural gas production facilities shall adhere to the monitoring and QA/QC requirements as set forth in 30 CFR 250.

(a) You must use any of the methods described as follows in this paragraph to conduct leak detection(s) of equipment leaks and through-valve leakage from all source types listed in §98.233(k), (o), (p) and (q) that occur during a calendar year, except as provided in paragraph (a)(4) of this section [which requires optical imaging for inaccessible areas as defined].

(1) Optical gas imaging instrument. Use an optical gas imaging instrument for equipment leak detection in accordance with 40 CFR part 60, subpart A, §60.18(i)(1) and (2) of the Alternative work practice for monitoring equipment leaks [This is italicised in the original. It would seem to refer to some document, but word searching this rule yielded no other occurrence.]. Any emissions detected by the optical gas imaging instrument is a leak unless screened with Method 21 (40 CFR part 60, appendix A-7) monitoring, in which case 10,000 ppm or greater is designated a leak. In addition, you must operate the optical gas imaging instrument to image the source types required by this subpart in accordance with the instrument manufacturer’s operating parameters.

(2) Method 21. Use the equipment leak detection methods in 40 CFR part 60, appendix A-7, Method 21. If using Method 21 monitoring, if an instrument reading of 10,000 ppm or greater is measured, a leak is detected. Inaccessible emissions sources, as defined in 40 CFR part 60, are not exempt from this subpart. Owners or operators must use alternative leak detection devices as described in paragraph(a)(1) of this section to monitor inaccessible equipment leaks or vented emissions.

(3) Infrared laser beam illuminated instrument. Use an infrared laser beam illuminated instrument for equipment leak detection. Any emissions detected by the infrared laser beam illuminated instrument is a leak unless screened with Method 21 monitoring, in which case 10,000 ppm or greater is designated a leak. In addition, you must operate the infrared laser beam illuminated instrument to detect the source types required by this subpart in accordance with the instrument manufacturer’s operating parameters.

(4) Optical gas imaging instrument. An optical gas imaging instrument must be used for all source types that are inaccessible and cannot be monitored without elevating the monitoring personnel more than 2 meters above a support surface.

(5) Acoustic leak detection device. Use the acoustic leak detection device to detect through-valve leakage. When using the acoustic leak detection device to quantify the through-valve leakage, you must use the instrument manufacturer’s calculation methods to quantify the through-valve leak. When using the acoustic leak detection device, if a leak of 3.1 scf per hour or greater is calculated, a leak is detected. In addition, you must operate the acoustic leak detection device to monitor the source valves required by this subpart in accordance with the instrument manufacturer’s operating parameters.

Comments:

• Is acoustic leak detection (5) limited to only a subset of required monitoring? Appears that way.
• It looks like (4) is an extension of (1) and indicates that, in some cases, using a camera is the only option.

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SO2 Modeling Guidance

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Although this guidance offers a "first tier" approach of using the "overall highest hourly background SO2 concentration from a representative monitor" (emphasis added), it goes on to seemingly stress the appropriateness of applying professional judgment when characterizing background by modeling nearby sources and by using monitoring data. It even goes so far as to suggest that you don't necessarily have to follow the modeling guidance in the 1980 Draft NSR Workshop Manual.

EPA SO2 Modeling Policy Memo, August 2010

I noticed, too, that Appendix W seems to encourage efforts to avoid double counting through use of modeling and monitored data. This link accesses a copy of the current version of Appendix W:

EPA SCRAM site with link to Appendix W

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Part 71 Minor Source Transition Policy

2/11/2010 e-mail from EPA R8 to Marathon Oil Company regarding implementation of the "Part 71 50% PTE Transition Policy." Link to the policy memo is included at the end of the post.

_________________________________________
Mr. Blanco,

EPA Region 8 received your letters dated February 10, 2009, announcing Marathon Oil's intention of utilizing the Part 71 50% PTE Transition Policy. Three facilities were identified in your submittals:

--Wolding 14-24H Oil & Gas Production Facility operating on the Fort Berthold Reservation

--Jay Sandstrom 34-31H Oil & Gas Production Facility operating on the Fort Berthold Reservation

--AH 34-23H Oil and Gas Production Facility operating on the Fort Berthold Reservation.

The purpose of the Transition Policy is allow those sources not otherwise subject to Part 71 permitting whose PTE is less than 50% of the trigger level for Part 71 (100 tpy) to avoid part 71 permitting until such time that a minor pre-construction permitting program is promulgated for sources operating in Indian Country.

This policy does not apply to avoiding pre-construction PSD permitting or NESHAP standards. It only applies to avoiding the Part 71 operating permit program for those sources who are not subject to any other CAA requirements and whose actual emissions for the previous year are less than or equal to 50 tpy. Please note that Part 71 is triggered upon start-up and an application is due with in one year of the start-up date.

Examples of ways that facilities can otherwise trigger Part 71 as defined in 71.3 and in the transition policy memo you attached to each of your letters, includes:

-- Any major source. Major source as defined in Part 71 includes major PSD and NESHAP sources.

-- Any source (including minor sources) subject to NSPS (part 60) requirements promulgated after July 21, 1992 unless the NSPS specifically exempts minor sources from Part 71 permitting.

-- Any source (including minor sources)subject to NESHAP (part 61 and 63 ) requirements promulgated after July 21, 1992 unless the NESHAP specifically exempts minor sources from Part 71 permitting.

-- Any Acid Rain source

You have identified each of these facilities as having potential uncontrolled VOC emissions of 106.82, 102.94 and 135.65 tons per year each, respectively; and actual VOC emissions of 25.18, 25.18, and 35.97
tpy, respectively. In addition, your submittal states that these facilities are not otherwise subject to Part 71.

Based on the information you provided, it appears these facilities are eligible for the Part 71 permitting exemption under the Part 71 50% PTE Transition Policy.

Please be aware that upon promulgation of the Federal Minor New Source Review Permitting program for sources located in Indian Country, the 50% PTE Policy will no longer be in effect. All facilities that utilized
this policy will be required to submit a minor NSR application to the EPA to make the actual emissions legally enforceable.

If you have any questions, please feel free to call or email me.

Kathy

***********************************************************
Kathleen Paser
Region 8 Air Program
303-312-6526
***********************************************************
US EPA Region 8
1595 Wynkoop Street
M/C 8P-AR
Denver, Colorado 80202
***********************************************************

Link to 1999 Transition Policy Memo

Boilers NESHAP Proposal - April 2010

"Boiler operators would be required to reduce mercury emissions by 50 percent as part of two new proposed rules to control air toxics from large and small boilers released by the Environmental Protection Agency April 30."

Would require annual testing for major and area sources. Existing small boilers and process heaters (L.T.E 10 MMBtu/hr) would need biannual tuning. Existing large boilers (area sources > 10 MMBtu/hr) would have to perform an energy assessment. Will cover boilers that burn coal, oil, biomass, and other non-hazardous materials. AWMA article includes link to EPA web site.

AWMA article

Trinity article

Of Boiler Rules and Biofuels
Martin Law article added 8/20/2010. Includes concise background and good short discussion of hazardous waste issue. Here's an excerpt:

"The key is whether the unit burns any “solid waste.” This leads to the question: when is biomass also solid waste? EPA’s original approach to this question was to exempt most materials that would be considered biomass (e.g., wood, food, agricultural byproducts – even manure, if burned) because they had not been “discarded.” However, EPA has now changed its rule to include an additional criterion: these materials are only exempted from treatment as solid waste if they remain in control of the generator. If these materials leave the point of generation, operators are now required to petition EPA for a “non-waste determination.”

EPA has indicated it will grant a non-waste determination if the boiler operator can establish that market participants treat the biomass stock as a fuel rather than a solid waste, and that the fuel stock has a chemical and physical identity comparable to commercial fuels, will be used in a reasonable timeframe, and has air emissions when burned comparable to traditional fuels. EPA’s determination is subject to notice, comment and hearing requirements, and, presumably, judicial review. Depending on how EPA handles this process, it could pose a significant administrative burden and uncertain time delays for fuel supply contracts between biomass energy project developers and timberland managers, farmers, and other suppliers of biomass."


Proposed Area Source Boiler MACT:
Here are some graphical outlines of the area source boiler MACT proposal. There are three graphics files: one overview and two subcategory expansions. The original file was created in a free mind mapping application called XMind which can be downloaded from this address: http://www.xmind.net/

XMind mind map

Overview jpg

Emission Standards jpg

Continuous Compliance jpg

Here are the proposed rules as published in the Federal Register. To access them, you'll have to log into Cyber Regs. You can use username 'kevinmathews' and password 'bisoneng'.

Major Source Boilers

Area Source Boilers

RCRA Waste Definition

CISWI NSPS Modification

Here's an MDEQ summary presented to CAAAC in July 2010:

MDEQ Summary Presentation

Coal Ash Proposed Rule

Pre-publication proposal released 5/4.

Coal Combustion Residuals Industrial Waste US EPA


E-mail from EPA to Grant regarding proposed rule's applicability to other fuel residues:


From: Livnat.Alexander@epamail.epa.gov [mailto:Livnat.Alexander@epamail.epa.gov]
Sent: Monday, May 10, 2010 1:15 PM
To: Grant Rodway
Cc: Souders.Steve@epamail.epa.gov
Subject: Re: Clarification on the Definition of CCR in the Proposed Rule to Regulate CCR Under RCRA

Mr. Rodway,

Your conclusion about the narrow definition of FFCs, to the effect that 'Waste from the combustion of oil, natural gas, and petroleum coke would not be subject to this proposed rule" is correct. This goes back to the May 2000 Regulatory Determination on Wastes from the Combustion of Fossil Fuels (http://www.epa.gov/fedrgstr/EPA-WASTE/2000/May/Day-22/f11138.htm) where we said that fossil fuel combustion wastes do not warrant regulation under subtitle C: "The Agency has concluded that no additional regulations are warranted for coal combustion wastes that are used beneficially (other than for minefilling) and for oil and gas combustion wastes (emphasis added)....However, EPA has also determined national regulations under subtitle D of RCRA are warranted for coal combustion wastes when they are disposed in landfills or surface impoundments...". This is the reason why since the 2000 Regulatory Determination we have focused on coal combustion wastes/residuals.

Regards,

Alex Livnat, Ph.D
Materials Recovery and Waste Management Division
Office of Resource Conservation and Recovery
US EPA (MC: 5304P)
1200 Pennsylvania Ave, NW
Washington, DC 20460-0001
Tel: (703) 308-7251
Fax: (703) 605-0595
Email: livnat.alexander@epa.gov

Proposed Gold Ore Processing NESHAP

“EPA is proposing to add the gold mine ore processing and production area source category to the list of source categories subject to regulation under the hazardous air pollutant section of the Clean Air Act (CAA) due to their mercury emissions. EPA is also proposing national mercury emission standards for this category based on the emissions level of the best performing facilities which are well controlled for mercury.”


“The gold mine ore processing and production area source category consists of facilities engaged in processing gold ore to recover gold using one or more of the following process units: roasters, autoclaves, carbon kilns, melt furnaces, mercury retorts, electrowinning, and/or pregnant solution tanks. There were approximately 21 gold mine ore processing and production facilities operating these processes in the United States (U.S.) in 2008. The majority and the largest of these facilities are located in Nevada. The other facilities currently operating are in Alaska, California, Colorado, Montana, and Washington.”

Notice:
http://companyweb/General%20Documents/Docs%20for%20posting/Gold%20Ore%20Processing%20NESHAP/NESHAP%20proposal%20-%20Au%20ore%20processing.pdf

MACT development:
http://companyweb/General%20Documents/Docs%20for%20posting/Gold%20Ore%20Processing%20NESHAP/MACT%20development%20-%20Au%20ore%20processing%20NESHAP.pdf

Mercury emissions evaluation report:
http://companyweb/General%20Documents/Docs%20for%20posting/Gold%20Ore%20Processing%20NESHAP/Hg%20emissions%20eval%20-%20Au%20ore%20processing%20NESHAP.pdf

Mercury emissions factors:
http://companyweb/General%20Documents/Docs%20for%20posting/Gold%20Ore%20Processing%20NESHAP/Hg%20Em%20Fctrs%20-%20Au%20ore%20processing.pdf

Proposed GHG reporting for petroleum and natural gas production - Subpart W

March 22, 2010 "(P)roposed rule for the mandatory reporting of vented and fugitive methane (CH4) and carbon dioxide (CO2) emissions from petroleum and natural gas industry facilities emitting 25,000 metric tons or more of carbon dioxide equivalent per year."

Greenhouse Gas Reporting Rule Regulatory Initiatives Climate Change U.S. EPA

NAAQS/MAAQS/Increment Tables

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Up-to-date NAAQS on EPA's web site:

National Ambient Air Quality Standards (NAAQS) Air and Radiation US EPA

Here's a table of NAAQS, MAAQS, increments, SILs, SMCs, significant emission rates, etc. Last updated 5/20/2011.

Letters regarding EPA regulation of GHGs -- MPA and others

Here are some letters regarding EPA regulation of GHG emissions:

MPA letters to Baucus --
http://companyweb/General%20Documents/Docs%20for%20posting/GHG%20letters/MPA%20letter%20to%20Baucus%202-10.pdf

http://companyweb/General%20Documents/Docs%20for%20posting/GHG%20letters/MPA%20letter%20to%20Baucus%203-10.pdf

MPA letter to Attny Gen Bullock --
http://companyweb/General%20Documents/Docs%20for%20posting/GHG%20letters/Intervention%20Endangerment-Bullock%20final.pdf

Letter to EPA Adminstrator Jackson from group of senators including Baucus --
http://companyweb/General%20Documents/Docs%20for%20posting/GHG%20letters/Rockefeller%20Letter%20-%202-10.pdf

Response from Jackson to Baucus --
http://companyweb/General%20Documents/Docs%20for%20posting/GHG%20letters/Jackson%20Response%20Letter%20-%202-10.pdf

Minor Sources in Indian Country - EPA Policy

March 7, 1999 policy memo.

"This memorandum discusses EPA’s transition policy concerning potential to emit (PTE) limits for stationary air pollution sources located in Indian country. Under this policy, EPA would treat a source as nonmajor for the purposes of the Federal Operating Permits Program (part 71) if its actual emissions area nd remain below 50 percent of the PTE thresholds for major source status, for every consecutive 12-month period (beginning with the 12 months immediately preceding the date of this memorandum) and it maintains adequate records to demonstrate that its actual emissions are kept below these levels."

EPA - Policy and Guidance Record - Potential to Emit (PTE) Transition Policy for Part 71 Implementation in Indian Country

Updated modeling guidance

Procedures for calculating the NO2 design value for comparison to the 1-hour NAAQS. Hopefully the BEEST post processor, and maybe others, will avoid the need to do this by hand.
EPA 1-hr NO2 Modeling Guidance


Excerpt from Comments of the Air and Waste Management Association's AB-3 Meteorology Committee Regarding New Dispersion Modeling Issues: PM2.5 and 1-hour for NO2 and SO2; March 12, 2010

"We now find ourselves in a unique regulatory period in which several new modeling procedures need to be established for both a newly regulated pollutant(PM2.5) and for 1-hour probabilistic standards for NO2 in spring 2010 and for SO2 in summer 2010. Associated with these pollutants and standards are important modeling issues that are not currently addressed in the Guideline. Regulatory dispersion modeling analyses have historically employed, in practice, several assumptions used to assure a conservative estimate of the modeled design concentration. Many of these assumptions are used only to simplify the analyses in the absence of more robust, scientifically sound information about the emissions sources and atmospheric conditions that affect the ambient pollutant concentrations. With the advent of several more stringent air quality standards, it is no longer practical to use redundant, overly conservative assumptions for simplicity or convenience. We encourage the development and implementation of robust methods for conducting regulatory air quality modeling analyses."

The document is here:
AWMA PM2.5 modeling comments


Here's a memo from EPA on modeling PM2.5. Basically, it "recommends" that, when modeling five years of NWS data for compliance with the 24-hr PM2.5 NAAQS, you should add the average of the first-highest 24-hr values for all five years to the 98% percentile of background measurements for three years.

2/26 & 2/24 EPA reviews and comments re. PM2.5 modeling

This supplemental EPA PM10/PM2.5 modeling memo addresses PM10 surrogacy demonstration and provides more extensive modeling guidance for PM2.5. The way I interpret it, it suggests using the highest 3-yr average across 5 years of NWS results for the annual average. For the 24-hr average, use the highest 3-yr avg. of H1H 24-hr results across 5 years of NWS model results.

March 23rd PM2.5 modeling guidance

EPA Regs Update - 12/09

Here’s a link to a database of brief status reports regarding EPA regulatory activity: http://www.reginfo.gov/public/do/eAgendaMain.

The status reports are compiled in a semiannual report available in pdf format. Here is a portion of the table of contents with some topics highlighted that I thought might be of interest to some of us.

http://companyweb/General%20Documents/Docs%20for%20posting/EPA%20reg%20status%20TOC.pdf