Affirmative Defense Under NESHAP General Provision Requirements

On October 16, 2009, the U. S. District of Columbia Circuit Court (the Fifth Circuit Court) vacated the “Startup, Shutdown, and Malfunction (SSM) exemption” allowed under the General Provisions in Part 63, Subpart A of the National Emission Standards for Hazardous Air Pollutants (NESHAP).  Under the vacated SSM exemption provisions, an affected source was required to minimize emissions during SSM events, but the exemption did not require the affected source to comply with the specific emission limits as provided for in the relevant NESHAP Subpart.  Now, unless the source specific NESHAP rule provides for separate emission limits during startup and during shutdown, the standard emission limits apply at all times, even during SSM events.  Check out John Egan’s previous 4 The Record article on the vacatur of the SSM exemption for more information.

While certain NESHAP rules issued or revised since the vacatur occurred now included separate standards for startups and shutdowns, malfunctions are treated differently because they are unplanned events.   Malfunction, as defined under 40 CFR Part 63, Section 63.2, means “any sudden, infrequent, and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner which causes, or has the potential to cause, the emission limitations in an applicable standard to be exceeded. Failures that are caused in part by poor maintenance or careless operation are not malfunctions.”  Unplanned shutdowns could qualify as malfunctions.

In NESHAP rules that have been issued since the SSM vacatur occurred, U.S. EPA has provided provisions for an affirmative defense to civil penalties for exceedances of emission limits or other violations caused by the malfunctions.  U.S. EPA has inserted the affirmative defense language into rules to ensure adequate compliance while simultaneously recognizing that despite the most diligent efforts, emission limits may be exceeded under circumstances beyond the control of the source (i.e., malfunctions do actually occur).  Typically, if a malfunction occurs that causes emission limits to be exceeded, the source can use the affirmative defense to avoid prosecution for a violation of its operating permit or other enforceable federal rules if the source properly notifies the Administrator (EPA or delegated authority).  Proper notification requires that an initial notification of the exceedances be made by telephone or fax as soon as possible but not later than two business days after the initial occurrence of the malfunction.  Also, a written report must be sent to the Administrator within 30 days of the initial occurrence of the exceedance of the standard and the report must include the following related information that:

1. Demonstrates that the excess emissions were caused by a sudden, short, infrequent, and unavoidable failure of air pollution control or monitoring equipment, process equipment, or by a failure of a process to operate in a normal or in an unusual manner;
2. Shows that repairs to the equipment were made as expeditiously as possible;
3. Indicates what steps have been taken to minimize the frequency, amount, and duration of the excess emissions;
4. Proves that excess emissions could not have been prevented through reasonable measures or planned for;
5. Shows that the malfunction(s) were not part of a recurring pattern;
6. Shows any bypass of controls was unavoidable;
7. Shows that all emissions monitoring and control systems were in operation, if possible;
8. Documents all actions taken to minimize emissions;
9. Demonstrates the affected source operated in a manner consistent with good air pollution control practices; and
10. Includes a written root cause analysis to determine, correct, and eliminate the causes of the malfunction.

Excess emissions resulting from malfunctions must be also be reported in semiannual reports, along with details of the malfunction event including a description of actions taken by an owner or operator to minimize emissions during a malfunction of an affected source.  The semiannual report must also include actions taken by the owner or operator of the source to correct the malfunction.

Most recently the Fifth Circuit Court affirmed a U.S. EPA action on Affirmative Defense with regard to a ruling on the provisions of the State of Texas’s State Implementation Plan (SIP).  In its finding the court re-affirmed, in part, the basis for its 2009 vacatur of the SSM exemption and how the U.S. EPA’s decision on Texas’s SIP conformed to the court’s opinion.  In that action, the U.S. EPA approved portions of Texas’s SIP and disapproved other portions on Affirmative Defense.  On July 30, 2012, the Fifth Circuit Court issued an opinion finding that the U.S. EPA was within its authority to approve in part and to disapprove in part the most recent revisions to the SIP that Texas had submitted to U.S. EPA in 2006.  U.S. EPA’s action allows an affirmative defense for unplanned SSM events, but it disapproved the portion of the Texas SIP revision providing an affirmative defense against civil penalties for planned SSM events.

The Fifth Circuit Court found that U.S. EPA’s decision to approve the affirmative defense for unplanned SSM events was in keeping with the Federal Clean Air Act (CAA).  The court’s opinion found that the CAA does authorize defenses that “”are ‘narrowly tailored’ to address unavoidable, excess emissions . . . [which] give the states the necessary flexibility to ensure that they remain in compliance . . . while still accounting for unplanned unavoidable events.””  The Fifth Circuit Court agreed with the U.S. EPA decision to disapprove the affirmative defense for planned SSM events, citing the U.S. EPA’s statements that “”its long standing position . . . that planned maintenance activities are predictable events”” and as such, are not appropriate to provide an affirmative defense for excess emissions during such events.

While this recent important decision by the Fifth Circuit Court reaffirms many of the parts of the court’s 2009 vacature and supports how the U.S. EPA has been crafting new source specific regulatory provisions since the court vacature, Texas and other states are considering what planned SSM activities other than scheduled maintenance that still may be able to benefit from an affirmative defense.  Activities related to planed SSM events dealing with industry actions other than planned maintenance could possibly be addressed in a state’s permitting regulations and approved SIP to provide for an affirmative defense.

Prepare to document as much as you can about the malfunction event including any evidence that permitted emission limits were not exceeded.  The importance of pre-planning for the collection of process and emissions information during possible malfunction events to best estimate emissions should not be overlooked.  The systems that your facility usually depends on to collect emissions and process information to meet state and federal regulatory requirements are likely to be offline or not provide certified emissions data during the malfunction event.  It is imperative that you determine before malfunction events happen, how you would make an alternate demonstration that the source is still operating within permitted limits, or at a minimum provide an estimate of the emissions level emitted during the malfunction event.  This preplanning is critical to providing a good affirmative defense.

The evidence should be as compelling as possible, but does not necessarily need to be from an approved emissions monitoring system.  After each malfunction event, a thorough review should be conducted to determine what can be done to prevent a recurrence of the same type of event in the future.  Any new preventative measures determined from such review should be incorporated into the source’s SSM plan.  It is equally important that the facility have written procedures for addressing each of the information sections required for the 30-day report. All staff involved with environmental compliance should be well familiar with the facility’s SSM plan.  Also, periodic training, revision of the plan, and review by legal counsel are important.  Reviewing legal actions taken by U.S. EPA for other facility reported malfunctions can also be very helpful in pre-planning for the event of malfunctions that may occur at your facility.

While it is not possible to identify all of the possible malfunction situations that may occur at your facility, you can be certain that eventually a malfunction will happen.  Developing a specific plan to address the core elements of an affirmative defense is simply smart planning.  Now is the time to prepare an SSM plan if it does not already exist, or to review and update your aging SSM plans to assure that you can meet all of the necessary elements of a good affirmative defense. Please note that while an SSM Plan is no longer specifically required by regulation, it is essential to have a plan of action in the event of SSM operating situations that could possibly result in an excursion.  Such forward planning will be invaluable if for no other reason than to provide the best legal defense possible.

Please contact ALL4’s John Slade at 610.933.5246 x36 or jslade@all4inc.com with any questions relating to affirmative defense.

ALL4’s: Is That Your Final Answer?

Last Month’s Answer and Winner:

There were multiple correct answers to last month’s rainbow question but it was Bridgette Rillema of Zeeland Farms who, recalling her high school senior physics project, answered that the second rainbow has its colors reversed.  Congratulations to Bridgette and thanks for those who participated in the contest.

Question:

As you may recall, the basis for last month’s question evolved from my annual trip to Niagara Falls, and even though I know the route by heart, I always consult a worn Rand McNally map before making the trip.  The consultation is more by habit than necessity as global positioning apps on my phone or in my car makes getting to my destination almost flawless.  But GPS apps won’t help you with the August “Is That Your Final Answer” question.  Most likely you will need an “old fashioned” map to discern the correct answer to the August question.  All of the borders between states in the continental United States follow rivers, other geographic boundaries, or surveyed straight lines; however, there is one location where the border between two states is a perfect arc centered on a radius of 12 miles.  Our question requires that you name the two states where the arc serves as the state border.  And for extra recognition in next month’s blog post, name the patch of land that, until 1921, was disputed as a result of this arc.  So pull out those old National Geographic United States maps or Exxon road maps and good luck!

Answer: 

Please e-mail your answer to final.answer@all4inc.com.  Include in the e-mail your name, answer, and address (to receive your prize).

ALL4’s Final Answer is a monthly feature of our Blog Digest.  It is designed to test your knowledge across the environmental field, quiz you on the building blocks of air quality rules, stump you on ALL4 general trivia, and challenge you with brain teasers that have perplexed us.  The first correct answer e-mailed to us will qualify the respondent for free ALL4 gear and will enter the winner in our end-of-the year “Final Answer Championship.”  The subsequent month’s Final Answer will identify the winner and the correct answer from the previous month’s question.  You must be an active subscriber of ALL4’s Blog Digest to win a monthly prize and be eligible for the championship prize.  ALL4 employees and family members are not eligible to compete.  Hope you enjoy this feature and good luck!

CSAPR: The Latest U.S. EPA Casualty

In a continuing trend, the DC Circuit Court (Court) handed U.S. EPA yet another loss in EME Homer City Generation LLC v EPA.  The casualty this time: the Cross States Air Pollution Rule (CSAPR).  In a 2-1 decision, CSAPR was vacated because the Court found that U.S. EPA exceeded its authority and violated the Clean Air Act (CAA) by imposing massive emissions reduction requirements on upwind states in a manner incompatible with the language of the law.  The Court also found that U.S. EPA was in the wrong by not allowing the states to establish their own plans to implement the required reductions within their states.

CSAPR was promulgated in August 2011 and required 28 upwind states to reduce interstate transport of sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions from their power plants (i.e., electric generating units (EGUs)).  CSAPR was developed pursuant to the CAA 110(a)(2)(D)(i) “good neighbor” provision, which requires upwind states with “significant contribution” to reduce emissions to downwind states.

This isn’t the first time the Court has been involved with U.S. EPA’s transport rule(s).  The original Clean Air Interstate Rule (CAIR) and CAIR Federal Implementation Plans (FIPs) were promulgated in May 2005 and April 2006, respectively.  The Court found both to be unlawful and vacated them in July 2008. A few months later, in December 2008, the Court had a change of heart and remanded both back to U.S. EPA.  In July 2010, U.S. EPA proposed a repackaged transport rule as the “Clean Air Transport Rule” which was later promulgated as CASPR in August 2011.  Immediately, companies, trade groups, associations and environmental groups took sides and a plethora of legal filings followed; some supporting U.S. EPA, others against.  CSAPR was stayed in December 2011.

With the vacature of CSAPR, at least for the near term, CAIR will remain in effect.  So, what are the implications of the vacature and what other questions does it raise?

• How will the vacature impact EGU operational plans and future compliance strategies over the next few years?
• Will U.S. EPA appeal the Court’s ruling?
• Per the Court’s ruling, how will U.S. EPA first determine each states exact “significant contribution?”  And, with states developing their SIPs to address the emission reductions, how will this elongate the implementation process? 
• How will other programs and rules such as National Ambient Air Quality Standards (NAAQS) compliance strategies, state implementation plans (SIPs), and Best Available Retrofit Technology (BART), to name a few, that rely upon CSAPR be affected?
• Will states use other CAA provisions to crack down on upwind contributors?  For example, New Jersey used CAA Section 126 provisions to petition Pennsylvania to curb emissions from a power plant.  Will EPA’s acceptance of New Jersey’s petition be subject to further legal challenges and at risk of being overturned?

These and other questions and additional implications will likely surface in the coming weeks and months.

Greenhouse Gas Confidentiality Determinations Finalized by U.S. EPA

On August 13, 2012 in Federal Register Vol.77, No 156, U.S. EPA announced the finalization of confidentiality determinations for regulations under the Mandatory Greenhouse Gases Reporting Rule.  In this same action, U.S. EPA also finalized amendments to defer the reporting deadline of certain data elements until 2013 and other elements to 2015, and to adjust the calculation and reporting of emissions from facilities that use best available monitoring methods (“BAMM”).  Published by U.S. EPA on October 30, 2009, the Mandatory Greenhouse Gas Reporting Rule which is codified in 40 CFR Part 98 (Part 98), mandates U.S. EPA’s collection of greenhouse gas (GHG) emissions data and other relevant information from large sources and suppliers in the United States for use when considering future policy decisions.  To address stakeholder comments concerning data reported that consists of trade secrets and other confidential business information (CBI), U.S. EPA published the Proposed Confidentiality Determinations for Data Required under the Mandatory Greenhouse Gas Reporting Rule and Proposed Amendment to Special Rules Governing Certain Information Obtained under the Clean Air Act (the CBI Proposal) on July 7, 2011.  These latest amendments represent the “next step” in a series of rulemaking actions in which U.S. EPA finalizes determinations regarding which categories of data elements will be protected as CBI.  More specifically, the amendments provide confidentiality determinations for most data elements to be reported under nine (9) subparts of the Greenhouse Gas Reporting Program and defer the deadline for reporting certain other data elements that are inputs to emission equations in three (3) subparts.  U.S. EPA has stated that the deferred reporting requirements for inputs to emission equations until 2013 for some data and 2015 for others have been made to allow for a more complete evaluation of issues regarding inputs to emissions equations, such as raw materials used and production volume.

You May Ask Yourself, “How Did I Get Here?”

At the age of 18, I thought the most important decision of my life was deciding which dress I should wear to prom.  Looking back now, I see that I couldn’t have been more wrong.  At the age of 18 I also made the decision to attend Drexel University for the next five years. Wait… five years to finish college? Upon hearing that someone went to college for five years, one usually assumes that the student had a little too much fun in college and had to take an extra year in order to graduate. In reality, Drexel professors take the “15-week semesters” and complete them in 10-week quarters. Oh, and summer breaks? Drexel doesn’t have those; we go to school all year round.

What is the benefit to learning the same material in less time and not having a summer vacation? Drexel students use the extra time to participate in six-month internships, known at Drexel as “co-ops,” to better prepare their student for careers after graduation. I was able to pick out three different full-time, six-month jobs within the field of Environmental Engineering. I spent my co-ops designing green infrastructure, investigating ground water and soil contamination, and monitoring air pollution, with the goal of learning what exactly I wanted to do after graduation. I graduated in June 2012 with a great degree and a resume that was able to show off five years of hard work without having to mention my experience scooping ice cream at Coldstone Creamery or teaching the backstroke to children at a local swim club.

My journey to ALL4 as a Staff Engineer began in my junior year when I attended a local Air and Waste Management Association (AWMA) event with Kevin Hickey.  After meeting Kevin and getting a sense of who he was as a consultant, supervisor, and business owner, I was sold on the idea of ALL4 Inc.  A year later, I had begun the application process with ALL4 and found myself at the same networking event.  At this point I had already memorized the faces of the ALL4 employees from the company website. While at the networking event I remember introducing myself to Meghan Schulz, with whom I was scheduled to conduct my phone interview the next day. Before I left, I made sure to talk to each of the faces I recognized as an ALL4 employee.

After surviving the phone interview and written expressions, the final step was a four hour interview in our Kimberton Office.  I wasn’t nervous about the interview; instead I was nervous about driving on the Turnpike for the first time in my life all alone in traffic.  After accidentally forgetting to grab a ticket, and thankfully meeting some very nice turnpike workers, I pulled into the Kimberton parking lot at 6:15 AM for my 8AM interview. I learned three very valuable lessons that day. Number 1 – don’t forget to grab the ticket on the Turnpike. Number 2 – when the GPS tells you the commute will take an hour, you shouldn’t assume that “with traffic” it will take you three hours.  And finally, Number 3 – ALL4 is the perfect fit for a recent graduate that wants to work hard, continue learning, and be exposed to a large variety of environmental clients and situations.  After one full month of working here I can say that I am very happy I chose ALL4. Although the work may be difficult at times, I am constantly learning and every day becoming a more integral member of the ALL4 community. 

Source Aggregation and the Plain Meaning of “Adjacent”

An interesting Court of Appeals decision was made by a three member panel of the Sixth Circuit this week (the Sixth Circuit is in Cincinnati and serves Michigan, Ohio, Kentucky and Tennessee).  The case involves aggregation of sources for purposes of Title V and pertains to a gas sweetening plant and surrounding sour gas production wells.  In 2005, Summit Petroleum Corporation, the owner and operator of the plant and gas production wells, and the Michigan Department of Environmental Quality (MDEQ) requested a U.S. EPA determination concerning whether the sour gas production wells and ancillary operations should be aggregated with the gas sweetening plant thereby making the combined entity subject to Title V air permitting as a “major” source (emissions greater than 100 ton per year).  It took about four years (and several U.S. EPA guidance memorandums) for U.S. EPA to make a final decision in September 2009 that Summit Petroleum Corporation should combine the emissions from the wells and thus should be a major source for Title V purposes.  The decision was appealed in 2010 and this week the Sixth Circuit Court of Appeals decided in a 2 to 1 rendering that the sweet gas plant and surrounding production wells should not be aggregated based upon the reasoning that U.S. EPA applied in September 2009. 

The Court’s position was based on the dictionary definition of “adjacent”, case law, and a disinclination to allow U.S. EPA to use a term in a fashion that, although is longstanding, is ultimately incorrect.  Specifically, the Court found the plain English definition of “adjacent” meaning “close to,” “next to,” or “adjoining” should be a primary condition for assessing aggregation, not as U.S. EPA has historically argued that “functionally related” facilities can be adjacent irrespective of the distance between them.  With respect to Summit Petroleum Corporation, the Court majority told U.S. EPA to reassess the operations in context of an unambiguous definition of “adjacent.”

This ruling has impact on both the Title V and New Source Review (NSR) permitting program.  Especially interested in the decision is the shale gas/oil drilling and transmission industry.  Moving forward, U.S. EPA’s options are to accept the ruling, request an en banc hearing, or to appeal the case to the Supreme Court.

Residual Risk and Technology Review Completed for a Pulp and Paper Industry NESHAP

On July 31, 2012, U.S. EPA finalized the residual risk and technology review conducted for the National Emission Standards for Hazardous Air Pollutants (NESHAP) for pulp and paper production areas of mills using the kraft, sulfite, semi-chemical, and soda pulping processes (40 CFR Part 63 Subpart S). The Clean Air Act [Section 112(f)(2)] requires U.S. EPA to evaluate the risk to public health remaining after the application of a NESHAP and to revise the standards, if necessary, to provide an ample margin of safety to protect public health or to prevent an adverse environmental effect.

U.S. EPA’s review concluded that there have not been  developments in practices, processes, and control technologies since Subpart S was originally promulgated that would result in cost effective additional levels of control beyond the current NESHAP requirements. In addition, the U.S. EPA’s residual risk analysis concluded that the risks from the Subpart S pulp and papermaking source category are acceptable, and that the current standard protects the public health with an ample margin of safety.

However, there were some noteworthy actions included in the July 31, 2012 final rule that will be effective once the rule is published in the Federal Register. U.S. EPA added a requirement to repeat air emissions performance testing once every five (5) years for facilities complying with the standards for kraft, soda and semi-chemical pulping vent gases, sulfite processes, and bleaching systems. U.S. EPA contends that the repeat performance testing requirement will help to ensure that facilities maintain control systems properly over time and therefore, promote on-going compliance with the standard. Specifically, repeat air emissions testing will be required for mills complying with the kraft pulping process condensate standards using a steam stripper. Repeat testing will not be required for knotter or screen systems with HAP emission rates below the criteria in 40 CFR §63.443(a)(1)(ii), decker systems using fresh water or paper machine white water, or decker systems using process water with a total HAP concentration less than 400 ppmw. The action also requires mills to submit electronic copies of performance test reports to the U.S. EPA’s WebFIRE database. The first of the 5-year repeat tests must be conducted within 36 months after the date of publication in the Federal Register.

In this action, U.S. EPA has also eliminated the startup, shutdown, and malfunction (SSM) exemption consistent with the 2008 Sierra Club v. EPA decision. Emission limits must therefore be met at all times, and mills are no longer required to develop and implement an SSM plan. U.S. EPA has added an affirmative defense to civil penalties for violations of emission standards that are caused by malfunctions in which a facility must demonstrate that specific criteria are satisfied to demonstrate the violation was caused by a sudden, infrequent and unavoidable event. Although the rule no longer requires mills to develop and maintain an SSM Plan, ALL4 believes that mills should think twice before celebrating by tossing their SSM Plans into the recycle bin. The procedures and checklists contained in an SSM Plan could someday be valuable in support of an affirmative defense claim.

Lastly, the action added four additional test methods for measuring methanol emissions from pulp and paper processes, as alternatives to EPA Method 308 of Part 63, Appendix A.

While the Subpart S has not been substantially changed, affected facilities will need to become familiar with the nuances of this action and be prepared to comply once it appears in the Federal Register. To review the July 31, 2012 notice in detail, it can be accessed here. 

Method 16C Approved for Total Reduced Sulfur (TRS) Emission Testing

On July 30, 2012, U.S. EPA announced that Method 16C is now an acceptable method for the measurement of total reduced sulfur (TRS) emissions.  One might ask, what is Method 16C, better yet, what compounds comprise TRS?  First, we’ll start with the definition of TRS.  TRS is comprised of the following four pollutants: hydrogen sulfide (H₂S), methyl mercaptan, dimethyl sulfide, and dimethyl disulfide.  Most of us associate TRS emissions with Kraft pulp mills and with its very characteristic odor.  Kraft pulp mills that are subject to 40 CFR Part 60 Subpart BB or petroleum refineries subject to 40 CFR Part 60 Subpart J, are required to periodically test for TRS.  In the past, three approved emission testing options were available for the measurement of TRS; Method 16, 16A, and 16B.  Method 16C combines components of existing Methods 16A (for TRS) and 6C (Determination of Sulfur Oxides from Stationary sources).  Sample gas is extracted from the stack through a heated probe and is then conditioned in a citrate buffer scrubber (as described in Method 16A).  From there, the sample gas is oxidized in a tube furnace, which converts the various TRS compounds to sulfur dioxide (SO₂).  The newly oxidized SO₂ is then analyzed using a real-time SO₂ analyzer (as in Method 6C).  The use of Method 16C for the testing of TRS is not required, just merely added as an alternative to the other available methods.

Deadline Extended for Promulgation of 1-Hour SO2 NAAQS

U.S. EPA announced in Federal Register Vol. 77, No. 150 published on August 3, 2012 that it is using its authority under the Clean Air Act (CAA) to extend by up to one (1) year the deadline for promulgating the initial area designations for the 1-hour sulfur dioxide (SO₂) National Ambient Air Quality Standard (NAAQS).  This will now require U.S. EPA to complete initial designations for the 1-hour SO₂ NAAQS by June 3, 2013.  U.S. EPA cited CAA Section 107(d)(1)(B)(i) which states that “Upon promulgation or revision of a NAAQS the Administrator shall promulgate the designations of all areas (or portions thereof) as expeditiously as practicable, but in no case later than 2 years from the date of promulgation of the new or revised NAAQS.  Such period may be extended for up to 1 year in the event the Administrator has insufficient information to promulgate the designations” for its justification of the extension.  U.S. EPA indicated that based on comments received from the September 2011 Draft SO2 NAAQS Implementation Guidance Document and the subsequent comments received as part of the stakeholder meetings that it remains significantly uncertain what analytical approach sources, States, and U.S. EPA will consistently and cooperatively use to make the determinations required under the CAA to determine attainment status with the 1-hour SO₂ NAAQS.  U.S. EPA further concluded that it currently has insufficient information to promulgate designations by June 2012.  U.S. EPA indicated that it intends to resolve the “issue” of how to determine an area’s attainment status by the end of the year.  However, U.S. EPA gave no indication of whether it will move forward with modeling or monitoring to determine attainment status.  U.S. EPA did indicate that it will move forward with the final designations for areas with monitored violations of the 1-hour SO₂ NAAQS. 

For more information on the history of the promulgation of the 1-hour SO2 NAAQS please refer to ALL4’s June 4TR article “How the SO₂ NAAQS Came Crashing Down On Us.” 

U.S. EPA also Proposing Secondary Visibility NAAQS With Updated Annual Primary PM2.5 NAAQS

In July, ALL4 posted a blog regarding U.S. EPA’s June 14, 2012 proposal to strengthen the National Ambient Air Quality Standards (NAAQS) for fine particle (PM_2.5) pollution.  As part of the proposed rule which is proposing to strengthen the annual PM_2.5 NAAQS within a range of 12 micrograms per cubic meter (µg/m³) to 13 µg/m³, U.S. EPA is also proposing a secondary visibility NAAQS within a range of 28 to 30 deciviews (dv).  Unlike a primary standard which provides public health protection, including the protection of health of “sensitive” populations such as asthmatics, children, and the elderly, the secondary standard provides public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings.  Many people may remember the term dv from the Best Available Retrofit Technology (BART) requirements from a couple of years ago that were part of the Regional Haze Program.  For those of you lucky enough not to be involved in this program, a dv is a unit of visibility proportional to the logarithm of the atmospheric extinction or more simply put, it is a measure of a noticeable change in visibility.  The dv scale is near zero (0) for a pristine atmosphere and a “just noticeable” change in visibility would be approximately one (1) or (2) dv.  Visibility is measured by the total light extinction of the sum of light scattering and light absorption components.  PM_2.5 causes the vast majority of light scattering along with atmospheric, or Rayleigh scattering which is natural scattering not related to air pollution, and light absorption due to particles and gases. 

The proposed secondary visibility standard is different from the BART requirements and Prevention of Significant Deterioration (PSD) Air Quality Related Value Analysis (AQRV) requirements because it will affect all counties in the U.S. not just Class I areas.  U.S. EPA has indicated that only three (3) counties would not meet the proposed 30 dv secondary visibility NAAQS and an additional six (6) would not meet the proposed 28 dv secondary visibility NAAQS.  Additionally, U.S. EPA believes that by 2020 only three (3) counties would not meet the proposed 28 dv secondary NAAQS based on expected reduction of visibility impairing pollutants from several current and upcoming federal programs including the Regional Haze Regulations and Guidelines for BART determinations.  For the primary proposed annual PM_2.5 NAAQS U.S. EPA anticipates making attainment/nonattainment designations by December 2014, with those designations likely becoming effective in early 2015.  However, the Clean Air Act does not specify a date for states to meet secondary NAAQS; U.S. EPA and States determine that date through the NAAQS implementation planning process. 

U.S. EPA initially intends to rely on a surrogate policy for the proposed secondary visibility NAAQS under the PSD program.  In their opinion, there is sufficient evidence to suggest that a demonstration that a source will not cause or contribute to a violation of the mass-based 24-hour primary PM_2.5 NAAQS serves as a suitable surrogate for demonstrating that a source does not cause or contribute to a violation of the proposed secondary visibility NAAQS under the PSD program.  However, past history suggests that surrogate policies are temporary and it appears likely that the use of complex visibility modeling and its inherent uncertainties will at some point become routine for projects triggering PSD.