United States Office ofAir Quality EPA-4541D-94-001 Environmental Protection Planning and Standards September 1994
.. Agency Research Triangle Pnrk, NC 27711 Air 

# GUIDELINE ON THE IDENTIFICATION AND HANDLING OF AMBIENT AIR QUALITY DATA AFFECTED BY SPECIAL EVENTS OR SPECIAL CONDITIONS

### DRAFr - 

### 9/8/94 EPA4541D-94-001 GUIDELINE ONTHEIDENTIFICA,.TION AND HANDLING OFAMBIENT AIR QUALITYDATAAFFECTED BY SPECIALEVENTS ORSPECIALCONDITIONS·
. 1.0 INTRODUCTION 1.1 Purpose 

### and Contents 1.2 Background 1.3 Changes Necessitated by the 1990 Clean Air Act Amendments 2.0 DATAUSAGE, TESTS, CRITERIA 2.1 Uses ofFlagged Data 2.2 Special Events and Special Conditions 2.3 Qualifying Tests 2.4 Supporting Criteria and Documentation 3.0 FLAGGING PROCEDURES 3.1 Data Flagging System 3.2 Submission ofSupporting Documentation 3.3 Concurrence and Review Flags FIGURE 3-1 Process Flow for Selecting and Applying A Data Flag FIGURE 3-2 Flow Chart for the Data Flagging Process TABLE 3-1
.. Time Requirements for "T" Flags 

### ArrE\"nIX A Listing of Descriptor Code Options AI'I'E\"D1X II Listing ofEvents Not Eligible For Approval as Special Events AI'I'E'iIllX C Listing ofAcronyms RFFERE'iCES

IiI." ,f,',**I~".nl"** 't'/I/,J, ('\ rlu' (;IIIt/('/tnt' nn till' /dell/lIIira/inn and Use ofAir QUll!in' Data Affectedby Exceptional**L:....t:.~:".,** ,11'1 J\fI.J
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### 21 22 

### A-I B-1
C-J1.0 INTRODUCTION 

### 1.1 Purpose and Contents The purpo.se o.fthis document is to. pro.vide guidanceo.n the procedures fo.r flagging and reporting ofdata associated with various circumstances: data validation, the submittal of informatio.n related to data, and/orrequest for special treatment accompanied by supporting dotumentatio.n.related to. an eventor conditio.n. 

### In

### summary, this documentco.ntains the following: Chapter 

### 1 provides a briefexplanation ofthe history ofspecial eventdata flagging and an introduction to this document. Chapter 2 presents data usage, tests, and the criteria used to determine if

### a data value can qualify fo.r the attachment o.fa data flag. Chapter 3 provides info.rmation o.n the procedures to. be fo.llo.wed fo.r flagging data and providing SUPPo.rting documentation fo.r flags. The review process that the U.S. Enviro.nmental Pro.tection Agency (EPA) will co.nduct is briefly described and examples o.f appropriate supporting documentatio.n are listed. Appendix A provides an explanation o.f several categories o.fevents and co.nditions that**_~;**____•**_.~**_____ma},-be_.used_to_describe_many_types_of_circumstances-affecting-data-values,---1'his-lisHs------------- based on the list o.f exceptio.nal events defined in the Guideline o.n the Identificatio.n and Use of Air Duality Data Affected by Exceptio.nal Events (EPA-450/4-86-007, July 1986, hereafter referred to. as the 1986 Exceptio.nal Events Guideline),l with mo.dificatio.ns to. include several events and co.nditio.ns which were no.t in the o.riginal guideline. It is impo.rtant to. no.te that thi., list is not exhaustive: it is intended o.nly to. pro.vide descriptive info.rmatio.n about certain cnnlilll!ln, that have been enco.untered by vario.us Statellocal air quality mo.nito.ring and**rcr"rttn~** J!!encies (hereafter referred to. as "repo.rting agencies") in past data-flagging CxpCfll·nccs. I\ppcnliix B pro\"ilies examples of events that sho.uld no.t be co.nsidered as special events**\\;lrfalltll1~** specIal treatmmt of data. Generally. these examples do. no.t meet the basic crlll'rt.1 th;!l W!luIJ support J special event claim..Appendix C provides the reader with a list ofacronyms used in this guidance document. 1.2 Background The 1986 Exceptional Events Guideline established procedures for the flagging and treatment ofmonitoringdata affected by exceptional, ornncontrollable, events. This guidance was intended to provide State and local officials withassistance in identifying data that.were believed 

### to have been influenced by

### the occurrence of

### certain specified natural ev6nts
.. Authority for this approach is set out in Appendix K of40 Code ofFederal regulations (CFR) part 50. The 1986 Exceptional Events Guideline mainly focused on problems relating to PM-I0 (particles with an aerodynamic diameter less thanor equal to a nominal 10 micrometers) monitoring data, butprovisions for flagging data from the other criteria pollutants were also included. The need for this guidance grew out'ofahistory of concern by States over EPA's treatment ofmonitored data. Through the late 1970s and early 1980s, certain airquality data obtained by monitoring stations in various States were not submitted to the EPA's National 

### Air Data Bank (NADB) as then required, due to concern on the part ofState and local air pollution officials thatthe

. data. ifused, would unfairly represent the air quality problems in their areas. The data in

question were not considered to be representative ofatmospheric conditions by these officials and in their view were atypical readings attributable to special events that warranted special tn:atment for the data by EPA. Concern by the States over EPA's use ofdata affected by special events began as early as h:oruary 1977, when the Office of Air Quality Planning and Standards (OAQPS), in its GUideline for Intemretation of Air Ouality Standards included this statement: "[RJegardless 01 th,'**~uum:.** ambient pollutant concentrations exceeding a National Ambient Air Quality StJlld.trd (:-->AAQS) constitutc a violation
...1 However, even then, the OAQPS guideline 11l1rl'I'J thc nced for a flagging systcm to identify data affected by exceptional events when it \IClll ,'II I,'**~Iatc** that "detailed infomlation cstablishing that violations due to uncontrollable ll.llul.1i**,,'urcc~** may Ix:**u~cd** in dctcmlining the feasibility of modifying control strategies." 1.111'1.**IL·~ul.lIl<lll~** promul!!ated by EPA regarding the development, adoption, and submittal ul "I.,IL' IIlIpiclllclitall(ln plans (SIPs) staled in 40 CFR part Sl.llO(f)l that "for the purposes
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### ofdeveloping a control strategy, data**deri~ed** 

### from measurements ofexisting ambient**l~vels** 

### ofa pollutant may be, adjusted to reflect the extent to which occasional natural oracCidental phenomena
... demonstrably affected such ambient levels during the measurementperiod." Treatment ofdata influenced by special events was also addressed in EPA's'March 1984 proposed revision to title 40 CFRpart50 (revising the NAAQS for particulate matter from a total suspended particulate (TSP) to a PM-IO standard). The proposed revision, which was**pro~ulgated** 

### onJuly 1, 1987 (52 FR24663)\ included provisions inAppendix K that allow States and EPA to considerthe influence ofrare orunusual events onPM-IO monitored data. Section 2.3 ofAppendix K Specifies that all data collected inaccordance with the minimum PM-lO sampling requirements of40 CPRpart 58 should be used when making comparisons to the NAAQS. However, section 2.4 ofAppendix K allows EPA to consider whether to discount or weight the effect ofambient air monitoring data for PM-IO influenced by exceptional events, That section notes that 'inclusion of(data from suchevents) in the, computation ofexceedances or averages could result in inappropriate estimates oftheir expected annual values." Section 2.4 gives EPA discretion to consider more than 3 years of representative data, orto consider other adjustments, as appropriate in order to "reduce the effect ofunusual events." This discretion is normally exercised by the appropriate Regional Administrator, in accordance with published guidance,**~~-:r:he-1986 EXGept-ional-Events.Guideline-was.intend€:d.lo.assist-EPA,State-and-looaII~~~~­**  

### of(-Icials in ensuring that air quality data associated with special events are given appropriate special handling to prevent misuse when calculating expected annual values. The EPA's general policy. as summarized in that guidance, was to consider excluding flagged data from usc in regulatory actions, This policy specifically did not create a presumption regarding the me or non-usc ofsuch data. hut rather was intended to offer a forum for States to present 1:1':\ with documentation supporting a request for exclusion ofreported data from use in**rc~ul:it.,r\** 

### actions, By estahlishing uniform procedures for flagging such data, EPA hoped to 11I1rr,\\

### c tlata suhmission and estahlish a consistent decision-making process for the use ofthe tl;tt.1 lI.,wc"cr, in practice, this process has often resulted in an erroneous beliefthat State alld I,,,al 

### "Iflclals could automatically exclude all flagged data fromregulatory actions. It

### is iInportant**(o~qaie** 

### here thai 

### t1a!!W!! ofdata 

### does not, bv 

### itself, result in the exclusion of 3

### such

### dotafrom regulatory decision making. Rather. flagging 

### is lUI important

### prerequisite 

### to consideration ofwhetherornot

### to grant

### such exclusion. Since the issuance ofthe 1986 guidance, EPA's data storage and retrieval system has been replacedby a new comprehensive air quality data system known as the Aerometric Information Retrieval System(AIRS), 

### Air Quality Subsystem (AQS)5. This improved data collection, storage, and retrieval system is EPA's system for collecting, flagging, and retrieving affected data under the procedures outlined inthis document. This document, 

# . . Guideline for the Identification and Handling ofAmbient Air 

### Qualitv Data Affected 

### By Special Events or Special Conditions (hereafter referred to as the 1994 Special EVents Guideline), describes the procedures for the flagging and reporting ofdata associated with various circumstances: data validation, the submittal ofinformation related to data, and/or. request'for special treatment accompanied by supporting documentation related to an event or condition. 1.3 Changes Necessitated by the 1990 Clean Air Act Amendments Passage ofthe Clean Air Act, as amended in 1990 (the Act), necessitated the review of a number ofexisting EPA regulations and guidelines. Guidelines on flagging ofdata affected by special events, including the 1986 Exceptional Events Guideline, are significantly affected by the addition ofPM-1O specific provisions in section 188(f)(subpart 4 to part D oftitle I) in the Act." This new section ofthe Act authorizes the Administrator ofEPA to waive, on a case-ny-case basis, certain provisions applicable to serious nonattainment areas for PM-1O and a specific attaihment date for moderate and above PM-1O nonattainment areas. The**exerci~<.'** ofthis waiver authority by EPA is predicated on a determination that anthropogenic s(\urces of PM-\0 do not contribute significantly to the violation ofthe PM-1O NAAQS in the ,m:;1 A specifiC attainment date may be waived ifEPA determines that nonanthropogenic, or mtuLII. s"urces of pM-IO contrihute significantly to the violation ofthe PM-IO NAAQS in the .lre.1 The EPA polk)' and guidance on the exercise ofthe section 188(f) waiver auth"rll\ " ;IJdressed in an EPA publication including serious area and other PM-IO 1l,'II.III,IIlIl\1el1l requirements. lIowever, the major implication of section 188(f) for the**Il""~"lc** ,,' J.lla I' that 11<1\\ all valid measurement data are expected to be used in the Je"CIl.III"1l ,,' all'area a, attainment or nonattainmcnt and that adequate documentation is , ,
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1 : i i .provided to support any related flags that are attached to reported data. The resulting review ofthe applicability ofthe 1986 Exceptional Events Guideline,has led to this new guidance document which establishes revised procedures for identifying and handling ambient monitoring data that may be influenced by special events or special conditions. New procedures are introduced for flagging any data value, whether below or above the NAAQS, as valid orrequiring explanatory documentation. Consequently, this document hereby replaces the 1986 Exceptional Events Guideline document. While the

.. majority ofthe changes in this revision apply specifically to the treatment ofparticulate matter data, there are some revisions to event descriptions that apply to the handling ofdata for other criteria pollutants
..Data for pollutants other than PM-I0that were eligible for special treatment under the 1986 Exceptional Events Guideline continue to receive such consideration under this revision. It is important to note that although the procedures for handling such data are subject to many ofthe same changes as apply to particulate matter data, the section 188(0 waiver provisions are specific to PM-lO.

5

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# I I I I I I I

### 2.0 DATA USAGE, TESTS, CRITERIA

2.1 Uses of

### Flagged Data Monitoring data have many uses. Identifying airquality trends and providing air quality information to the public orthe scientific community are uses meriting data flagging and are not intended to result in regulatory relieffrom the effects ofdata influenced by special events orspecial conditions. The use ofdata to make NAAQS comparisons and in conducting SIP regulatory activities are subject to legislative and regulatory limitations. Comparisons ofmonitoring data to the NAAQS are controlled by section 1l0(a)(2)(B)(i) ofthe Act and procedures for making such comparisons are contained in 40 CFRpart50. This document does not specifically address the procedures for analyzing the impact offlagged data on policy decisi()ns and other SIP activities for PM-IO. Not all situations meriting data flagging are intended to result inregulatory relieffrom the effects ofdata influenced by special events or special conditions. Data submitters may simply wish to provide potential data users with an indication that additional infonnation is availahle on a particular data1;et._Ihis-can_be_accomplished-by-f'lagging-the-data-set-and------- suhmilling the explanatory infonnation. Data flagging allows the data submitter to

.supplement a data record with useful.infonnation that can enhance the use ofthe data for

such non-regulatory purposes. Appendix K to 40 CFR part 50 specifies that all data that are collected under the prnccdun:' contained in 40 CFR part 58 should be used when comparing an area's air quality tn tile'**~**:\t\QS. Prohlems arise. however. when data are interpreted and acted upon without a etc;,r lllldcrq;mding ofthe circumstances and conditions under which they were collected. It " l1o,t UllL'''IlII1HlO for two or more interpretations to be possible when examining ambient all co"kCIIlr;II1<'1l data affectcd hy s['ecial events or special conditions. In such instances. it is ([ltk.1i til.,1 ;,Jultl(\l1al infllmlatinll he a\'ailahle for use in shaping the conclusions on which a**rC~lll.'to'n** 

## .'-\'''11 will he hascd since (lnly one interpretation can he given legal effecl. 6Flagging procedures allow the data submitter to mark a data value(s) in a way that

, '

, 

### . refers the data user to additional information that might influence its(their) use. Such additional information might be used to support claims that data have beenunduly influenced by an event orcondition such that special regulatory handling ofthe data is' warranted. For instance, ifan area's concentrations ofPM-IO result in its designation as a nonattainment area, that 

### area will be 

### required to meetcertaincontrol requirements. If, however, it

### canbe demonstrated thatthe PM-lOexceedances were theresult ofemiSsions from aneventthat is noi likely torecur, then it'may be possible to avoid the area's designation as nonattainment altogether. ForPM-lO, this is 

### permitted by Appendix K to 40 CFRpart50. Flagging such data for special consideration when

# making comparisons to the NAAQS 

### can achieve this end. The EPA would make any such determinations 

### in accordance with the procedures contained in this guideline. 

### 2.2 Special Events and Special Conditions There are a number ofsituations in which a data flag may be applied to request regulatory relief. Some ofthese scenarios are described in Chapter 

### 3. They may be categorized as either special events orspecial conditions, depending on surrounding circumstances and supporting information. They may also be characterized as anthropogenic (or manmade) or nonanthropogenic in nature, subject, again, to review ofsupporting documentation. 

## FACTOID

.... pedal el'ents are discrete occurrences. eitheranthropogenic or /I(lnontlzropogenic. that can be classifiedas not likely to recur. Special conditions are well-documented circumstances that can have a significant II/flumc£' on the ambient concentrations ofapollutant andare ofa recurring /I,I/llr(', Tl1l"Y may resull.for inslance.from anthropogenic emissions originaling 

### ,,./1111 (lur,I/I/e ofIlze Uniled States. ornonantirropogenic emissions. such as wind "'.,\\ 1/ dllslfrom a nonanthropogenic source.
Iii C'1'1\l'r.t!, LI'A npcC:l' to exclude data intluenc:cd hy special events and which qualif J 1"1 d,IL,**11."·~111~,** Irtlill L'(l!1lpanson with the NAAQS, l3y excluding the data. EPA hopes to 7 

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! :avoid situations inwhich data that are not representative ofanarea's expected air quality are used to dictate control requirements and Strategies for that area. Data resulting from events that are likely to recur orfrom special conditions will not 

### be eligible for exclusion from NAAQS comparisons. However, forPM-lO values associated with special conditions, such data may beusedunder section 188(f) to support a request for a waiver ofserious nonattainment area control requirements or specified attainment dates should the area meetthe waiverpolicy criteria. Section 188(f) refers to, among otherthings, norlanthropogenic sources.· Thus, events caused by nonanthropogenic emissions that are likely to recur and special conditions, as defmed in

### thiS Section, will no longerbe eligible for exclusion from NAAQS comparisons. (Note that the 1986 Exceptional Events Guideline had implied'that all events caused by nonanthropogenic emissions would be considered "exceptional events", thus eligible for exclusionfrom NAAQS comparisons.) 2.3 Qualifying Tests This sectionpresents the tests thatmust be applied for data to qualify for the attachment ofa special event data flag. The data flags that simply validate the data value, or indicate the availability ofadditional information on the data value may be applied without "qualification". Supporting documentation for potential special events must address the following tests: 

## FACTOID Recurrence Test: The event's likelihood ofrecurrence. Culpability Test: The causal relationship between the event and the measured airquality dota.
The ICrIll "likelihood ofn:currence" cannOI he absolutely defined so that there is no f<\(\111 1<'f 1I11erpn:lalion. Whal may he considered a special event fOf one part ofthe country mal Ix: Il"rlG!1 1m another. Ii is obviously impossible to predict future air quality events, Ihcrel>'fe. Ihe "likelihood ofrecurrence" will he based on historical information. It is the 8reporting agency's responsibility to collect, review, and submit appropriate historicaldata and information to sufficiently support and advance their claim that the event is notillcely to recur and a causal relationship between the source ofthe event and the data value(s) has been established. 

### Inorder to promote consistency in the process, however, the following general boundaries are recommended when evaluating information'in support ofthe Recurrence Test and theCulpability Test. Generally, for all events, the reporting agency mustuse a mihrrnurn offive years ofhistorical information when establishing the likelihood of recurrence. Special event documentation should bebaSed onthe most recent 5 years for which information is available. The reporting agency must work with the Regional Office for cases where five years ofhistorical information (i.e. meteorological data) is not available to determine ifthe likelihood ofrecurrence may bebased on the merits ofwhat.is available, Ifan event occurs once in the five year period (i.e. the event in question is the first such occurrence in five years), then the event should be considered as not likely to recur. This scenario satisfies the Recurrence Test for the attachment ofa special event data flag. The Culpability Test for the causal relationship between the event and the affected air quality data must be based on the following: 

# • 

# • Consideration of all relevant raw data, such as air quality data, meteorological data, and traffic counts, etc.; A demonstration that the monitor did not report similar pollutant concentrations (or chemical constituents ofparticulate matter) before and after the time period in question; • Evidence that the wind speed and direction at the time period in question were such that the pollutant was transported from the source to the monitor reporting the data during the time period in question; • Appropriate modeling and/or filter analysis data as specified by the criteria in S<:<:tion 2.4. Ii " Imponant to note that while arplying a special event flag to the data set is t;II1t;lI1hlllllt til applying for sp<:cial treatment ofthe data, only EPA's acceptance ofthe causal rl'i.llIlllhlll['**~<:(wccn** a qualifying event and the data values and the evaluation of a recurrence 9 

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### claim will result inthat special treatment.. Although objective criteria are applied whenever possible, there is an unavoidable degree ofsubjectivity associated with the interpretation ofthe impact ofspecial events and special conditions. Consequently, the review ofany supporting documentation and the fmal decisions regarding the use offlagged data will be the ultimate responsibility ofEPA Regional and 

### Headquarters Offices. 2.4Supporting Criteria and Documentation 

### .' Inorder for EPA Regional and Headquarters Offices to make fmal decisions regarding the use offlagged data, it is 

### extremely important that reporting agencies support flag applications with all appropriate documentation to create as complete a recounting ofthe event orcondition as is practicable. Therefore, the criteria outlined below are intended to promote consistency in the submission ofsupporting documentation and data management by the reporting agencies and EPA. The process offlagging data by eventtype,as done prior to this guidance, is being replaced by procedures for the flagging and reporting ofdata associated with circumstances including: data validation, the submittal ofinformation related to data, and/or request for special treatment aci:ompanied by supporting documentation related to an event orcondition. Descriptive codes,derived in part from the list ofevents in the 1986 Exceptional Events Guideline, may be 

### used to provide descriptive information about the nature ofthe**evenLOLCQndition~Cbapter--3-contairu;-fuFth(W-inf0Fmilli0n-0n-the---------­** 

### dcscriptive codes. There are six basic types ofcriteria that may apply individually, as appropriate, to the cvents or conditions in question to 

### support their eligibility for special treatment or handling. /{ep(ming agencies should examine the circumstances surrounding the collection ofa data set I{I en,un: that the applicable criteria have been documented before attaching a flag to the data 'L"I S,'me criteria may apply to the majority ofthe events or conditions, while others may ;Irrh 

### I.' (lnly a few. The qualifying criteria used to document a potential special event must 1'1' 

### 'utlJ.:IL'nl to determine that the event is not likely to recur and should establish a causal rL'i.III"Il,IlIl'**~Iwecn** 

### the source ofthe event and the data value(s), The criteria options are a,I(,111 1\\' 

### • \Irtl"orulog)' Criterion

- Meteorological information may be used to indicate the 10upwind versus downwind conditions or defmed wind speed and wind direction at the time and location ofthe event or condition relative to the monitor. This criterion is particularly but notexclusively important whenevaluating events or conditions that occur within a rnicroscale, a middle scale, or neighborhood scale8 from a monitoring station. • Modeling Criterion9

- Conclusions may be supportedby dispersion orreceptor modeling. 1biscriterion is oftenused for those types ofevents orconditions that occur at some distance from a monitor, generally overregional orurban scale dimenSions (>4km)8: • Filter Content Criterion - A significant percentage ofthe monitor filter media content mustbe attributable to the event orcondition. In general, EPA believes a significant contribution from a particular event orcondition would constitute 85

### % ofthe material ona filter. For certainevents or conditions, deviations from this general 85

### %guideline may be necessary and should be agreed upon mutually by the reporting agency and the EPA. The EPA and the reporting agency may also agree that filter analysis is not necessary for a particularevent or condition if other supporting documentation clearly establishes a source-receptor relationship. When it is not possible for a reporting agency to successfully document the event using filter analysis, the reporting agency should notify EPA in its supporting documentation. It is recommended that filter analysis take place within six months immediately following the data collection date. This will minimize the possibility of damaging or losing the filter. 

# •

• Monitor Proximity Criterion

- The event or condition must occur within some dIstance from the monitor as defined by the appropriate measurement scale as related to the monitor location and the event's source. The monitor proximity cnlerinnis used with most event types to document the source-receptor**r<:lall'Hl~hip.** Like the meteorological criterion. this information is particularly 11lIp"rtalll fm e\'ents or conditions that occur within a micro-, middle, or**'I<.·,~hh"rh(\(ld** scale distance (0-4 kilometers) from a monitoring station. Tilll!' Criterion· Two types oftime criterion may he used to document a I 1 1 ' i

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: rpotential special event orspecial condition. The first ofthese would state that the questionable data was collected within some specified time during andlor"after the event orcondition. This timerequirement would 

### be used to establish a sourcereceptor relationship between the data and the event orcondition. A second type oftime criterion considers duration, where, after a limited period oftime the event or condition is no longer considered special. This second time criterion would 

### be nsed, for example, to document the temporary nature ofan eventand to demonstrate the likelihood ofrecurrence ofevents. • Quantitative Criterion

- Some numerical parameters may be applied to illustrate the size and nature ofan event orcondition.

12I 

### I

### 3.0 FLAGGING PROCEDURES
3.1 DataFlagging System A data 

### flag is an identifying mark applied to any data 

### value that indicates the availability ofadditional infonnation describing the causes of, orcircumstances surrounding the collectionof, the data 

### value, Three 

### types ofdata 

### flags canbe used 

### by the data 

### reporting agency as listed below:

....

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iuidiiiiinaUi!tormationon a

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### "}:JMi}!.·,t/?{;t 2. 

### Validity "V"Flag

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## tojrifJicliilihhtadJili**··"·';)~.ilA~h;;;i;;t;** validatedby the reporting agency. " ;.. various reporting agencies with data values that exceedthel:{AAQS. 3. Treatment "T" Flag

- to notifY. EPA olthe re]lQ11ingJlgency-'-:LinlenLto_seek
_____ _ relief from certain regulatory requirements resultingfrom the affect ofa potential special event (see definition. Section 

### 2.2) on the data value(s). Application of a Type T flag indicates that supporting documentation will be submittedby the reporting agency tojustify any reliefsought. Application ofa Type T flag must be made within 30days after the endofthe reporting period. (The reportingperiod forNationalAirMonitoring Stations (NAMS) or State/LocalAirMonitoring Stations (SLAMS) ends 90 days after the end ojthe calendar quarter in which the data value occurred. For Special Purpose Monitors (SPMs). this reporting agency is generally required to rl'{JOrt all data. with appropriate T flags. by July I oftheyear following the rear in which data were collectedw)**l'nli~e** Jaw with Type T nags, Jata values with Type lorY nags are not related (0 the

. occurrencc' 01 a**~recial** C\'en! [)ata values with a Type V nag would, therefore. be used

### without special treatment for regulatory purposes and may be submitted to AIRS-AQSat any time. Data values with a Type I flag indicate the availability ofadditional informati6n for conducting scientific analyses, documenting circumstances worthy ofnote, orensuring that data relevant to exercising the waiver provisions in section 188(f) for PM-lO are properly represented. Applying a Type T flag to a data set signals thereporting agency's intent to seek relief from certainregulatory requirements resulting from the effects ofa potential 

### special event. WIi.en special treatment ofdata is requested by the reporting agency, it must be supported by



### . 

# . additional information in the AIRS-AQS descriptor fields showing the nature ofthe event. This supporting m:i,terial can include information onmeteorological conditions, filter analysis results, and other information as described in Section 3.2ofthis document. It 

### is important to understand that no assumption can be made onthe ultimate disposition ofthe data until the documentation has been received, reviewed, and any request for special treatment approved by EPA. It is not EPA's intent to remove all subjectivity from the data flagging process. Ongoing communication between the data collecting agency and the appropriate Regional Office are critical during determinations ofapplicability ofdata flags and the ultimate disposition offlagged data. The procedure for determining the appropriate flag to apply to a data set is ilIustrated in Figure 3-1. 3.2 Submission ofSupporting Documentation Supporting or explanatory documentation may be submitted for many applications, Reporting agencies may elect to submit explanatory documentation for any data value, Timely**~uhmittal** 

### of information relating to any flag is recommended so data users will have 'Ieees,s III 

### explanatory information for flags as soon as is practicable. When the documentation is suhmitted to 

### support a contention that a special event lu,tlllc" 'pccial treatment of air quality data. two tests must be addressed in the d,,-'UI11L'I1t:III(ln: Test 1: 

### the event's likelihood of recurrence, and Test 2: a causal relationship kl"L'c'l1 thc' 'rcclal event and the measured air quality data, These qualifications must he c'I.II'I"hL'J III CIllketin): Inlllnnation from all availahle sources to 

### create as complete a**rL""UIlI"I~** 

### "I thc c'\'Cnl anJ II' effects as is practicahle, 14 ; , 

# , ,

\ iIn order for reporting agencies and EPA to reach timely closures, onthe review of special event flags, time requirements identified in this document must apply to 

### Type'T flags. Data values for PM-lO resulting from special conditions may be associated with an area's request for waiverofserious nonattainment area control requirements or specified attainment dates should the area meet the section 

### 188(0 waiver policy criteria (see Section 

### 2.2). Therefore, itis recommended that the time requirements for the submissionof supporting documentation

### be applied for data values associated with 

### Type I flags for special cortditions. This recommendationis only meant to assist reporting agencies inkeeping track ofthe informationthatmay 

### be useful in supporting future applications ofwaivers under section 

### 188(0 ofthe Act. Supportingdocumentationfor potential special events must 

### be submitted to the Regional Office within 

### 60 days ofthe T flag submittal period. The only exception to therequirement to submit special events supporting documentation to the Regional Office is for special events caused by stratospheric ozone intrusion. In those cases, the OAQPS has the responsibility for reviewing';.the affected ozone data, the special event documentation, and the subsequent concurrence/non-concurrence actions. As such, the reporting agency should send supporting documentation for stratospheric ozone intrusion affected data to the OAQPS in addition to the Rc!!ional Office.

,**''---~---[-)H€u,m~nta~i0n-and-analyses.csupp()rting-the-appHcation-of-a-flag-to-a-candidate--event** o"'t------ C!lntllUon includes, but is not limited to, news reports, meteorological records, work sdwduks. 

### PM-IO filter analysis, and other supporting documentation establishing the event In question as a matter ofpublic record. It is generally preferable to provide some Inl••nnatHln ofthis type to the AIRS-AQS electronically, where it can be directly linked to**tli~ Ila~~ed**  data set through the use of it's data descriptor fieW. In cases where this is not 1" "'It-Ie, IIil: supporting documentation may be submitted to EPA in hard copy form, •**"'·I\,·nlll~ a~"nci"s**  should ensure that hard-copy documentation is carefully referenced in the .1)'1'" 'I" 1.lie· :\IRS "QS data descriptor field.) \ II
..JJIIHlnaI lkscriptor code, inputted within the AIRS-AQS descriptor field, must also k IlkIlJ,kJ I
.. ;dl"" 1m d;lIa sorting amI other retrieval options, These codes are used to 

## ",,!!.
..:,' 1111: 1I.IIUr': "I Ihl: sJ1Ccial event or special condition. A listing ofthese descriptor 15code options is included inAppendix A. Examples ofthetypes ofpublic and technical infonnationthat may be used to support and advance claims ofdata influenced by a special event orspecial condition are discussed below. As stated above, reporting agencies may electto submitpublic and technical infonnationexplaining any data value, notjustthose associated withpotential special events and special conditions. (Public and technical infonnationmay provide

### the background for the briefwritten summary ofevent orcondition circumstances thatmay be included inthe free-form comment fields associated withthe flagged data set's descriptor field.) 1. Meteorological reports
- These reports would beused to substantiate the meteorology criterion and could be included in any modeling requirements that may be necessary. Meteorological information is generally helpful indetermining a causal relationship between an event orcondition and a certain data value(s). 2. Particulatematter filter analysis

- Results from the fIlter analysis would beused to substantiate the fIlter corttent criterion. Analysis offIlters collected before and after an event.or condition may be used to support it's occurrence claim. Some examples of circumstances that would normally require a filter analysis include high winds, high pollen count, long-range pollutant transport, sandblasting, construction/demolition, agricultural tilling, highway construction, and salting and sanding ofstreets. 3. \"('ws reports, photographs, and videos

- News reports, often accompanied with ph(ltngraphs and/or video, are used by the media to illustrate the severity and scope of an event or condition, particularly ifit effects a large population center or land mass, hents and conditions that may be recorded through news reports, photographs, and/Or \ IdL'o, include high winds. volcanic eruptions, forest fires, high pollen count, "<Instruction/demolition. rerouting oftraffic, highway construction, infrequent large**""lhL'fIn~\,** industrial upset conditions. structural fires, sandblasting, salting/sanding of 'i'L'l'ts.**r"('lin~** operations. and prescribed burning, Aerial or satellite photographs may ,d, ' t><: u'ed III analysis of long·range pollutant transport. -\ :O-d,'ntifi(' Clhwnations. scientificjournal articles, seismic reports
- Scientific ,,10'('[\,111<'11' and an:II\'\e.\ are required to determine if an event or condition is the result ,,' 'ir,II<"i'IlCTIL' ",one Intrusion and long-range paHutant transport. The size and 16 i :

'---J


## .

,

! ; • i

; f

i '

: ! i ; ! ; i ' I 

### i**~** i
. , ,

,

# . • !

j" ; f i ' I

### severity ofvolcanic eruptions may be illustrated by records ofseismic activity in addition to scientific observations. 5. Operating permits.and work orders

- Operating permits and work orders are often examined when a reporting agency is evaluating events orconditions involving anthropogenic sources. Thereporting agency must document compliance or noncompliance withpermit conditions and 

### control requirements. Events which are most likely to involve the examination ofa source's operating permit and/or work orders include sandblasting, construction/demolition, highway construction, traffic rerouting, salting and 

### sanding ofstreetS, roofmg operations;prescribed burning, and industrial upset conditions. 

### 6. Traffic and parkingreports
- Inevaluating events or conditions caused, at least in part, by mobile sources, a reporting agency will often provide traffic and parking reports. Traffic reports usually accompany the documentation for highway construction, rerouting oftraffic, and infrequent large gatherings. 7. Ticket sales records

- Ticket sales records could be used by a reporting agency to determine ifthe number ofpeople at a gathering could be 

### categorized as an infrequent large gathering. 8. 

### Production schedules and records, inspection reports, and repair orders

- These -'-' -'

------types-of-records-arrd.eports-may-lYe-use-d-m"lle"SC1ibetlre 

### impact ofinc!ustnal'u"p"'s"'eTt

-------- condition on air quality data values. This type ofupset condition might be caused by

; ! 

### either start-up or shut-down ofan industrial process or faulty control equipment. The reporting agency must establish the maintenance record and availability ofspare parts r"r the facility, They must document the actions taken to reduce emissions during the L"\'L'n1 'J 

### Firl' department records

- Fire department records can be used to document the time. I"c.ltl,'n, anu extent of a structural fire, J
.. ' 

### ('(lucllrn'nn' and Review 

### Flags 11iL' 

### ,unllll\sion or supporting documentation is necessary for the EPA (0 

### evaluate anu rl"r,'nd "1'l'r"pnately to Type T data flags. (EPA concurrence on a Type 

### i or V flag is not Ill'Cl'''.ln I**l'la~** 

### evaluations are carried out hy the appropriate Regional Office (except for 17data flagged for stratospheric ozone intrusion, which are reviewed by 

### the OAQPS), and should be completed within 30days ofthe supporting docmnentation submittal period: At any time during the docmnentation review process, the Regional Office may inform the appropriate OAQPS ambient airquality management and monitoring personnel ofthe disposition ofthe data. Type T flags will be reviewed by the Regional Office to ensure that (1) the supporting docmnentation adequately defmes the event as not likely torecur; and (2) the supporting doJmnentation establishes a causal relationship between the event and the data values. If these requirements are met, the RegioDal. Office will attach a concurrence flag to 

### the data set. The original Type T flag will remain on the data as well. In some instances, EPA. may request additional docmnentation before taking a position on the status ofa flag. Ifrequested, additional documentation must be submitted by the reporting agency within 30 days ofthe EPA request. The EPA must make a fmal detennination ofthe flagged vaJue(s) within 30 days ofthe receipt ofall needed supporting documentation. The Regional Office will thenenter the data flag representing their position in the AIRS-AQS. Ifthe above requirements are not met, the Regional Office will attach a**nonconcurrenc~** flag to the data. The reporting agency may submit further evidence supporting the flag within the next 30 days following the attachment ofEPA's nonconcurrence flag. After the receipt of additional supponing documentation, the EPA shall make a final detennination of the flagged value(s) within 30 days. Ifit is necessary for the reporting agency and EPA to negotiate additional time for submitting supponing documentation, the Regional Office should con,enatl\ely grant these extensions to facilitate adequate technical review by the reponing agL'lk" II I' imp(lnant ((1 state here that it is the intent of this guideline to resolve data**Ib~~Ul~** l"ue, as timely as possihlc, The Regional Office may change its original llPlk,"kllrrCIl,'L' h;I'eu <1n such additional evidence, 11,111 "'L'IH, 11I1CL' tlwught to he a special event. does recur within the five year period ,,11,'1 Illl'**"Il~ll\.t1II\.'currcncc** was recon.lt:d. the Regional Office should reevaluate its position ,\11 till'**"II~IIl,tI** "'Ilcurrcnce !lag, At that time, the Regional Office should change its origin"l "<'11, IJlll'II,,'**t1.l~** l<\ " 11,HICtHlCUrrence !lag to more appropriately reflect the recurring naturc 18 , 1 

### : ; :

i:

i i

### ofthe event. This change is particularly important when the Regional Office is reviewing data to be used for policy decisions and for accurately flagging data to be used in later trends analyses and standard reports. The EPA has reviewed and evaluated several options for accommodating these new procedures in the AIRS-AQS. One identified need involves creating a separate AIRS data field that would contain a status code indicating EPA's current position onthe original data flag. As a result, EPAuses the following additional codes in this data field to indicate the cutrent status ofthe initial Type T data flag throughout the documentation review process:



### 1.

2. U.S.EPA RegionalSpecialEvent "S"Flagc.a be appliedwhen EPA agrees with thereporting agency'sflag andrequest thal the data be given special treatment. 3. U.S.EPA RegionalNonconcurrence "N"**Flag--=--lLIl11m:nm:ur:r:ence-code,-to~------­** 

### be applied 

### ifEPA does not agree that a requestfor special data handling is justified; or 

### ifEPAfinds that an appliedflag, in the absence of such a requestfor special data handling, is notjustified underthe specific criteria for applying such aflag. 4. 

### U.S.EPA AIRS-AQSfield isblank

- indicates that EPA has not responded to the reporting agency's request, orthat the reporting agency'sfield contains an 

## "ror "V"flag which doesnot require EPA's response. :\ Il<'" chart descrihing the reporting agency's and the Regional Office's data-reporting anJ**Ib.~~II1~** procetlures is inclutled in Figure 3.2. A summary ofthe time requirements for tilL' 'Uilll1l"I<l11 of n:porting agency "T" nags. supporting documentation, and U.S. EPA**RC~I<'!1.!1** OtTlcC llaic'S are included :n Tahle 3-1.
191
. 

### Dataarecollected & 

### submittedtoAIRS byreportingagency

Do NO dataappeartobe r"'IIl---------------<,affectedbya specialevent

oesthe 

### onditionaffectin orspecial ndition? YES Is

### the NO**~** 

### thedata YES 

### eetthespecialcondition**>--.~:=--<** 

### eventorcondition

. likelyto recur?



# , def. inSect.2.2? YES 

### Attacha TypeI flag to data.

Flag Options I

- infu_ a,aiil,hl" \

- \alidal,·d data (hlall'" . no nag 

### Does documentation show eventas theculpable source?
Flag Options I - info. available V

- validated data (blank)

- no nag


### Submitdataflag to AIRS-AQS & 

### add descriptorfield information, as needed. YES 

### Attacha TypeTflag to data.

Figurt· .3.1 Process Flow for Selecting & 

### Applying a DataFlag 

### 20, 

### , Reporting (Stateilocal) agency measures & 

### reports a datavalue (DV) 

# DV Reporting agency Dag



### Re iona! Office**Questio~s** 

### forreporting agency

### &**o~ers a~**  

### needed

### Mo~itoring & 

### Air
____.... to establishrecurrence& 

### causa!relatIOnship, Programs Contactsfor If

### requested, add'Iinformationmustbeprovided

pOllutantofinterest byreporting agency within 30days ofrequest.

As necessary. ,inform HQofproposed disposition & 

### initiatediscussion ofpossible im[llications on overall air program,

Re).'l<lnal Office Joint Coordination Flag (t-.ltlfllttlrinp & 

### Air Proprams Contact,) Add Re).'itlnal flag (SIN) 

### within 30 days (Ifti,

### 'clllllentation submittal period or3D d,,\', 

### .ilter reLjul'st for add'i information, 

## sNFigun'**.'.~,** 

### Flow Chart for the Dala'Flagging Process**~I**i i

, i Reportingagency reports data to EPA via AIRS-AQS.

T flag applied to data value(s) by reporting agency. Reporting agency submits supporting documentation. Regional Office evaluates supporting documentation. As needed, Regional Office requests additional information from reporting agency. Regional Office makes final determination to concur or not to concur with T flag. If Regional Office does not concur with T flag. reporting agency may submit further evidence to support their request for special event concurrence. Regional Office makes change to their original decision 

### ifwarranted by evidence presented by reporting agency. Ambient air monitoring data collected at 

### NAMS/SLAMS must be reported in 90 days after the end ofthe calendar quarter inwhichthe data were collected. For SPMs, data mustbe reported and certified by July 1 ofthe year following the year during whichdata were collected. Must be applied within 30days after the end ofthe reporting period described above. Mustbe submitted within 60 days afterthe submittal for T Mustbe completed within 30 days of

### the supporting documentation submittal period. Reporting agency has 30 days to submit additional documentation. Must be made within 30 days ofrecc;:iving the requested additional information. Must be submitted within 30 days of EPA's application ofa nonconcurrence flag. Any necessary changes must be made within 30 days ofthe receipt ofadditional evidence.

Table 3-1. Time Requirements for "T" Flags & Supporting Documentation

22Appendix A - Listing ofDescriptor Code Options The followirig is a listing ofdescriptions and AIRS codes for events and conditiOns. These codes are tobeused as part ofthe documentation required to support special event and special condition claims. Note thatthese are examples ofevents orconditions that may qualify for special treatment orhandling buttoo oftendo not. They will allow data users to sortdata by categories, therefore the codes may be used with any flag (Types "I" or "T") that
. simply indicates the availability ofadditional information for data values. The codes do nofreplace the detailed documentation necessary to supportthe tests and criteria listed in Chapter

### 2. HIGH WINDS-SUSPENDEDtRESUSPENDED PARTICULATEMA TfER (PM)

- AIRS Code A Definition: High whi.ds combined with high PM levels due to suspension orresuspension ofcrustal material or other particulate matter. The event description should contain information demonstrating the presence ofanhourly wind speed ofgreater 

### than what normal peak prevailing wind conditions are for the affected area, with no precipitation or only a trace ofprecipitation (observed as scattered drops that do not completely wet or cover an exposed area up to a rate of0.01 inch/hour).11.12.13
STRATOSPHERIC OZONE INTRUSION (03) - AIRS Code B Dcfinillon: A stratospheric ozone intrusion occurs whena parcel ofair originating in the ,trattlspherc. avcrage height 20 km (12.4 miles),14 is entrained directly to the sur!;lCl' tlf the carth. Y()I.L\"(:EHl'JYrIO:O-;S 

### (CO, S02, N02, PM)

- AIRS Code C IktJllllh'" lliv CIIII"I,ln (lr cJCctilln of volcanic materials at the Earth's surface from a crater

A-I

### SANDBLASTING (PM) - 

### AIRS Code 

### D Definition: Sandblasting orgritblastingrefers to the temporary use ofabrasive blasting with pressurized air for surface preparationpurposes at a given location.
VEGETATIVE FIRES (CO. PM) - 

### AIRS Code E Definition: Any frre in which vegetative matter is burned. To the extentpossible, the freeform comment field in the descriptor field should include an indication ofwhat type ofvegetative matter burned (e.g., forest, rangeland, etc.) and offrre type.

.Fire types may include:

Wildfire

- generally defmed as an uncontrolled fire in 

### vegetation started bynature, arson, or accident that requires suppressive action to protect natural resources orvalues associated with natural resources, as well as private property. Prescribed·natural fire

- a wildfrre for which a conscience decision has been made by a land manager to allow the fire to bum in a controlled and restricted manner for a land management purpose. Prescribed fire

- a fire intentionally ignited by a land manager for a land management purpose (e.g., ecosystem improvement, hazard reduction, etc.). 

# I CLASS 

# I SIZE, ACRES 

# II A ,;; 0.25 B 0.26·9.9 C 10· 99.9 D 100
. 299.9 E 300
. 999.9 F 1000 ·4999.9 (; ;, 5000 I A·2 . 

# ,

; f

i ;

### This table lists the class and size designations offorest frresl6•**Clas~** 

### A and 

### B fifes are generally associated with monitoring data collected on a microscale ormiddle scale range from the fife, while Class C and larger fifes would also be expected to affect data collected within a neighborhood, urban, regional scale.


### STRUCTURAL

## FIRES (CO. PM)

- AIRS Code 

### F Definition: Any fife involving some kind ofstructure, such as a building, residence, industrial complex, commercial establishment. 

### HIGH POLLEN COUNT (PM)

- 

### AIRS Code G Definition: A pollen count index above 25 grains/cm2 or 1000 grains per cubic meter. 17 The pollen count index is usually obtained one oftwo ways: 1) by use ofa coated slide mounted on a circular plate that is generally mounted onthe top ofa seven or eightcstory building with an unobstructed air flow, or 2) volumetric method (i.e. counting the number ofgrains per cubic meter.) Other recognized methods for measuring pollen levels may be used.

- .-- -

••**~.~--------~----------------------------------------~----------------------------** 

### CIIDIICAL SPILLS AND INDUSTRIAL ACCIDENTS (CO, S02, N02, PM)

- AIRS Code H Dd'inition:**El11i~sions** that result from accidents such as fire, explosions, power outages, train**lkrailll1ent~.** vehicular accidents. or combinations ofthese. 

### ]]{\FFI(.!'.·\TTER:,\S 

### (CO)

- AIRS Code I Iklll1lll"11 .\ "'l1dlll<'l1**re,ulttn~** from a major accident (rather than frequent minor accidents) ,'I ,1",1'1 Jur;lIlon Ohqruclilln. such as demolition or construction. During these ,''!IJIII<'II' Iile ILld 01 traffic I11<JY increase until it exceeds the maximum capacity A-3ofa given street orhighway. Speeds are reduced substantially and stopp;lges may



### .. occur for short orlong periods oftime because ofdownstream congestion.
CONSTRUCTIONffiEMOLITION (PM)

- AIRS Code

### J Definition: The building/destroying/renovationofany residential, institutional, commercial or industrial building, structure, facility, orinstallation.
AGRICULTURAL TILLING (PM)

- AIRS Code K' Definition: The act ofpreparing dry soil for cultivationor for controlling the growth ofweeds by the use ofmechanical devices during periods with an hourly average wind speed greater than what is expected for that area. HIGHWAY CONSTRtJCTION (PM)

- AIRS CodeL Definition: The act ofbuilding anew, or repairing an existing, highway, road, or street.
REROUTING OF TRAFFIC (CO)

- AIRS Code M Definitilln: A temporary deviation or detour ofvehicular traffic because ofan accident, construction. or demolition.

llelll11111111 III,' ,ll'l'liCalion Ill' salt and/or sand to the road surface to increase traction and/or I"c'\,'Ill Ihe ,urLIL'l' water from refreezing after it has melted.

A-4 . !

! :

, :



### , , ,
I t

, 1

### INFREOUENT LARGE GATHERINGS (CO, PM> •AIRS Code 0 Definition: A gathering ofmore 

### than 10,000people (5000 cars) at anyone time and at a single location. Unusual traffic congestion may be associated with the event. 

### ROOFING OPERATIONS (PM, S02)·AIRS Code P Definition: The process ofbuilding, repairing, orrecoating the external upper covering ofa house orbuilding that involves the application ofa petroleum-based material (usually heavy residuals from a refining operation) to a roof. The material is heated and then sprayed orrolled onto the surface.


### CLEANUP AFTER A MAJOR DISASTER (CO, PM, S02) • AIRS Code R Definition: Forthe purposes offlagging, major disasters are serious public misfortunes for which State orFederal reliefhas been granted. 

### INDUSTRIAL PLANT START-UPS, SHUT-DOWNS, PROCESS UPSETS, OR Ggll':r.ROr, EQlJIJ!MEN+ MALImNC+IQNS (Q3, N02, 

### J!M, CO, S02, 

### J!B)-AIRS Code S Definition: Emissions that result from plant start-ups, shut-downs, process upsets. or control**~quipmcnt** malfunction or combinations ofthese events.**[VJJ~R':\TlO'AL** 

### POLLUTANT TRANSPORT (PM)

- AIRS Code T Ikllll1ll{l1l '1 r:tll'p"n of a paniculate matter over international horders." The original source <II lill' pollution may he anthropogenic or nonanthropogcnic. This code, ifused in ,<lIlIUIl(11<1I1 with a reponing agency's type "I" nag. may he used to document**ll'dJrrlll~** ,pcci;d conditions in suppon ofa PM·IO waiver application. A·5

### OTHER TYPES OFEVENTS (03. CO. PM. 

### S02. N02. 

## pm -AIRS Code U The aforementioned list oftypes ofevents is based onthe EPA's previous experiences with the circumstances surrounding special events. There may betruly discrete and rare events that are not likely to recur that are not listedwithinthis appendix. For these other cases, the reporting agency should use the "Othertypes ofevents" code. This code indicates that, although anevent may qualify for a Type T flag, it is notadequately described by one . ofthe descriptor categories. (As appropriate, EPA

# will include new descriptor codes for special events into the AIRS-AQS flagging options.) 

### OTHER TYPES OF CONDmONS (03. CO. PM. 

### S02. N02. PB)

- 

### AIRS Code W A reporting agency may use this code for two purposes. The first is to document a special condition that is not accurately described by any other descriptor code in this Appendix. For PM-IO special conditions, this type ofdocumentation may be used to support a waiver application. The second use is to provide general information on a data value(s) that may be ofinterest to others who are using the data: This second case does not imply that the data will be treated as a special condition, it only serves to inform others ofthe circumstances surrounding a data value(s).

A-6 { 

## ,

i ,

! I

, , , 

### ,

, 1 : i

### Appendix B - Listing ofEvents Not Eligible For Approval as Special Events

The following information is provided as a list ofexample events which would not generally be considered as special events as defmed 

### in Section 2.2 ofthis document.. This list is not exhaustive. Reporting agencies may wish to docmnent these types ofevents by**a~ching** an "J" flag to the data value(s) and providing supplementary information inthe appropriate descriptor fields 

### in A1RS-AQS.
A. Implementing Transportation Controls Transportationcontrormeasures are not considered special, and the data collected during implementation oftransportation controls should not 

### be flagged for special treatment. If, however, traffic must 

### be temporarily rerouted during the implementation ofthe transportation control measures or some congestion occurs due to initial start-up ofthe transportation plan,
.the data collected at monitors near the rerouted traffic or congestion may be flagged for special treatment. 

### I1 Stagnation/Inversions**~------~S(agnation-and-inversions-are-frequent-climatologi"cal-occurrellCt:sthatllliIsCo"'e--------­** considered in evaluating whether a control program is adequate to attain and maintain the I"AAQS. An inversion is·said to occur at a point, or through a layer, where temperature increases with increasing height. Surface-based inversions are those that extend vertically fr(llll the surface to some altitude aloft. Inversions occur very frequently, are usually short**II\~J. ~lnJ**  disperse shortly after sunrise.'9 Because inversions are expected to occur 'le'llue'lllh and arc part of normal weather patterns, they are not considered special events for Ihl' rurr'''"' (It tla)!)!ing data, \1."'11.111<111 cpis(I<..\es arc periods of more than I day with surface wind speeds of ,l'lIl'"i1ll -1 ITll'IL'rs'second or less and no precipitation or frontal passage, In some parts of Ih,' { IIlIl'd SI,lll", sta)!nali(\n usually persist for an extended period oftime, and they can
B-1affect an entire**ai~** basin; therefore, they are not generally considered for special treatment.20,21 C, High-Sulfur Oil Refining High-sulfur oil refining refers to the process ofrefining crude oil with a sulfur content that is 20percent orgreater thanthe designcapacity ofthe refining operation, Because this is**~common** practice atmany refmeries, it is notconsidered to 

### be a special event for the 

### , purpose ofdata flagging, D, Sootblowing from Ships Sootblowing from ships is a method 

### inwhich air is used to remove deposits that may build up on the walls ofthe vessel's boiler tubes, This is a commonpractice that is either· controlled or limited (in many areas ofthe country) by establishing opacity limits. Because these activities are common, sootblowing from ships (like general sootblowing from utility and industrial boilers) is not considered a special event and data affected by this activity would not receive special treatment.
E. Noncompliance--Local Sources Limited noncompliance oflocal sources can be expected occasionally as a result of**rr"ces~** upsets or malfunctioning control equipment. These events are usually classified as "ursets" or "malfunctions" as defined by the applicable State or lotal agency regulations, or thL" 1l1;IY he considered a violation of applicable emission or opacity limits. 

### Ifthese events arc e;lu,,:d hy upsets or malfunctions, they should be so noted and reported to the appropriate ("Illr,'I**a~ency.** If they constitute a violation. the appropriate legal remedies will be taken. II**k~,t1** aClllln is taken. the air quality data collected in the vicinity ofthe source will in all Ilkllil,,,,,1 be u,ed in the legal proceedings. and any appropriate limitations associated with Ilk· ,1.11.1 \\"l11J he reviewed and evaluated as part of the legal process. Becausedata ,.'lkdL·c\**Jl1r1!1~** nllncomrliance conditions have special uses and the source is required to n"IIIL lilL· SI,lte tit the upset or malfunction. noncompliance of local sources is not considered

B-2 i**~.** I ;

, I

### F. Unusual Lack ofPrecipitation Lack ofprecipitation alone would not be considered as a special eventbecause·ifhas very little impact on ambient air pollutant levels. Lack ofprecipitation ordrought conditions combined with high winds, however, could be considered as a special event and documented with the descriptor code for high wind suspended/resuspended particulate matter. G. Data not MeetingApplicable Ouality Assurance/Quality Control Requirements ofthe EPA/State/Local Agency Occasionally, it may be necessary to invalidate ambient airmonitoring data onthe basis ofnot meeting appropriate quality assurance/quality control requirements orbecause ofa monitor malfunction. This action is 

### not considered as a special event ora special condition.

A more appropriate way to treat this type ofdata is to use null value data codes, as defined in the AlRS-AQS system, to indicate that invalid data have been deleted and to provide an indication ofthe nature ofthe problem, for example poor quality assurance results or general power failure.

B-3Appendix C**~** Listing ofAcronyms
I. AIRS - Aerometric Infonnation Retrieval System 

### 2. AQS

- 

### Air QualitySubsystem (ofthe Aerometric Infonnation Retrieval System) 

### 3. CFR

- Code ofFederal Regulations 

### 4. CO

- CarbonMonoxide 

### 5. FR

- Federal Register 

### 6. NAAQS

- National Ambient Air Quality Standards 

### 7. NADB

- National Air Data 

### Bank 8. NAMS

- National Air Monitoring Stations 9. N02 - Nitrogen Dioxide 10. 

### 03

- Ozone II. OAQPS

- Office ofAir Quality Planning and Standards 12. PB

- Lead 13. PM-IO or PM

- Particulate Matter with aerodynamic diameter less than or equal to a nominal 10 micrometers 14. SIP

- State Implementation Plan 15. SLA!\IS -StatefLocal Air Monitoring Stations I() S02

- Sulfur Dioxide 17**SI'\I~** - Special Purpose Monitors (e.g. special study. industrial, federal non-EPA) IS TSP· Tntal SusPended Particulate 1'1 l .S.F1',,\ or EPA

- lJniled Stales Enl'ironmental Protection Agency



### C-IREFERENCES 1. Guideline on the Identification,and Use ofAir Ouali1y Data Affected by Exceptional Events, Upited States Environmental Protection Agency, Office ofAir Quality Planning and**Standard~,** Research Triangle Park, NC, 

### EPA450/4-86-007, July1986. 2. Guideline for the Interpretation ofAir Ouality Standards, United'States Environmental Protection Agency, Office ofAir Quality Planning and Standards, Research Triangle Park, 

### NC, OAQPS No. 1.2-008 (revised February 1977). 3.; United States Code ofFederal Regulations, Title 40, Part 51, Section51.110(1), July 1993. 4. United States Code ofFederal Regulations, Title 40, Part 50, Section 50.6, July 1993. 5. Aerometric Information Retrieval System (AIRS), Air Quality Subsystem (AQS), United States Environmental Protection Agency, Research Triangle Park, NC. 6. Clean Air Act, as amended in 1990, PL 101-549, November 15, 1990. 7. Federal Register, Title 40, Part 51 fmal rule ·State Implementation Plan Requirements for Serious PM-I0 Nonattainment Areas", Volume 59, Number 157, August 16, 1994, pp.41998-42017. 8, United States Code ofFederal Regulations, Title 40, Part 58, Appendix D, July 1993. 9, Guideline on Air Quality Models (Revised), United States Environmental Protection ----'
______**A!!cnq~._Office-oLAir-Quality-f!lanning_and--Standllrds,Researeh-'Friangle-Park;-NC~,**----- EPA-45012-78-027R. (NITS PB 86-245-248), July 1986, and subsequent revisions. I() h:deral Register. Title 40, Part 58 final rule "Ambient Air Quality Surveillance**l{q~ulations".** Volume 59, Number 155, August 12, 1994, pp. 41626-41629. II I<cccptllr Modt.:! Technical Series. Volume I, Overview ofReceptor Model Application I,' 1'.1I1lculate Sourct: Apportionment. United States Environmental Protection Agency, (IIIicC III Air Quality Planning and Standards. Research Triangle Park, NC. EPA4'11 -l SI(lI(13. July 1981. 

### I: 1\,',l'I'I' 'f \1.",kl Technical Series. Volume II, Chemical Mass Balance, United States I """"Ilfllclllal I'r(lleclion Agency. Office ofAir Quality Planning and Standards.**1~'c""",!J1 nan~k**  Park. NC. EPA-450/4-81-016h. July 1981. I;**I~,,"i'l'"** \1.'<.kllcclllllcal Series. Volume III. User's Manual for Chemical Mass I\., ;,,',., \ 1.',kl, I'(lIll'l1 Stales Environmcntal Prolection Agency, Office ofAir Quality 1'.,,,,,,:1,: .II\J '\1.lno:lrO\. Rescarch Triangle Park. NC. EI'A-450/4-90-004. January

### 14. Mohnen, V.A., and E.R. Reiter. International Conference on Oxidants, 1976

- Analysis ofEvidence and Viewpoints Part 

## m. The Issue ofStratospheric Ozone Intrusion. United States Environmental Protection Agency, Research Triangle'Park, 

## Ne, EPN600/3-77/115, 1977. 15. Bates, R.L. and J.A. Jackson. Glossary ofGeology. Second Edition: American Geological Institute, Falls Church, VA, 1980
...' 16. Personal Communication with Doug Francis ofthe United States Department of Agriculture (USDA) Forest Service, National Forests ofNorth Carolina, Asheville, North Carolina, June 1994. 17. Air Pollution Aspects ofAeroallergens (Pollens), National Air Pollution Control Administration Consumer Protection and Environmental Health Services, Department of Health, Education, and Welfare, September 1969. 18. PM-tO State Implementation Plan Development Guideline, United States Environmental Protection Agency, Research Triangle Park, NC, EPA450/2-88-001, 

### June 1987. 19. Barry, R.G., and R. 

### J. Chorley. Atmosphere. Weather, and Climate, 6th edition, Routledge, New York, NY, 1987. 20. DeMarrais, G.A. Air Pollution Concentrations Associated with Stagnation and Restricted Visibility, Eastern North America, August 1976, United States Environmental Protection Agency, Environmental Sciences Research Laboratory, Research Triangle Park, NC, 1980. 21. 

### Briggs, G.A. Stagnation Diffusion Observed in a Deeply Pooling Valley During STAGMAP, National Oceanic and Atmospheric Administration, Research Triangle Park, NC, United States Environmental Protection Agency, Atmospheric Research and Exposure Assessment Laboratory, Research Triangle Park, NC, EPA/600/A-92/233, 1992. ! ! 

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### , TECHNICAL REPORT DATA (Please readInslruclior.:; an revcrse before complcting) I. REPORT NO. 2. 3.**RECIPI~T'S** ACCESSION NO. EPA-454/D-94-001
•. TITLE AND SUBTITLE S. REPORT DATE Guideline onthe Identification and Handling ofAmbient Air September 1994 (draftdocument) Quality Data Affected by Special Events or Special Conditions 6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO. Lee 

### Ann B. Byrd, Breda Phillips

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO•

.

# . U.S. Environmental Protection Agency Office ofAir Quality Plannillg and Standards Technical Support Division (MD-14) & Air Quality II. CONTRACf/GRANfNO. Management Division (MD-15) Research Triangle Park, NC 27711 12. SPONSORlNG AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED Director Draft report as ofSeptember 8, Office ofAir Quality Planning and Standards 1994 Office ofAir and Radiation 14. SPONSORlNG AGENCY CODE U.S. Environmental Protection Agency EPAI200/04 Research Triangle Park, NC 27711
15. SUPPLEMENTARY NOTES Supersedes uGuideline on the Identification and Use ofAir Quality Data Affected by Exceptional Events". EPA-450/4-86-007, July 1986.

16. ABSTRA(°T This document provides guidance on the procedures for flagging and reporting data associated with various circumstances including data validation, the submittal of information related to data, and/or the**requestin~** for special treatment ofdata accompanied by supporting documentation related to a special event or speCial condition.

17 KEY WORDS AND DOCUMENT ANALYSIS 

### • PI \("HII'10RS b IDENTIFIERS/OPEN ENDED TERMS c. COSATI Flcld!Gruup Amniolll 

## .11' lLtl.t**11.1~~**lilt' Air Pollution Control Amniolll 

## .11' J.Il.! ,,!\IJa[[(l1l Ambient Air Monitoring Data ExcepI111ll,d L'\ enl
... Air Quality**Mana~ement** SpeCIal II,'nl' SpeCial (""TlJill"'" It< IlI"':!-: I ... 

### ,,', ',. I**~** SHTRITY CLASS 1fIt'/,orrl 21 NO {)I' PACii:S Unclassified 37 Rek",c ! lillllllleJ**~fI** SECTRfTY CLASS (Pug" 22 PRICE Unclassified 1-:1':\ h"l11
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