CFR 2011 Title40 Vol2 Part50 AppL

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40 CFR Ch. I (7–1–11 Edition)Pt. 50, App. L

(impactor) where the suspended particulatematter in the PM2.5 size range is separatedfor collection on a polytetrafluoroethylene(PTFE) filter over the specified sampling pe-riod. The air sampler and other aspects ofthis reference method are specified either ex-plicitly in this appendix or generally withreference to other applicable regulations orquality assurance guidance.

2.2 Each filter is weighed (after moistureand temperature conditioning) before andafter sample collection to determine the netgain due to collected PM2.5. The total volumeof air sampled is determined by the samplerfrom the measured flow rate at actual ambi-ent temperature and pressure and the sam-

pling time. The mass concentration of PM2.5

in the ambient air is computed as the totalmass of collected particles in the PM2.5 sizerange divided by the actual volume of airsampled, and is expressed in micrograms percubic meter of air (µg/m3).

3.0 PM 2.5 Measurement Range.3.1 Lower concentration limit. The lower de-

tection limit of the mass concentrationmeasurement range is estimated to be ap-proximately 2 µg/m3, based on noted masschanges in field blanks in conjunction withthe 24 m3 nominal total air sample volumespecified for the 24-hour sample.

3.2 Upper concentration limit. The upperlimit of the mass concentration range is de-termined by the filter mass loading beyondwhich the sampler can no longer maintainthe operating flow rate within specified lim-

its due to increased pressure drop across theloaded filter. This upper limit cannot bespecified precisely because it is a complexfunction of the ambient particle size dis-tribution and type, humidity, the individualfilter used, the capacity of the sampler flowrate control system, and perhaps other fac-tors. Nevertheless, all samplers are esti-mated to be capable of measuring 24-hourPM2.5 mass concentrations of at least 200 µg/m3 while maintaining the operating flow ratewithin the specified limits.

3.3 Sample period. The required sample pe-riod for PM2.5 concentration measurementsby this method shall be 1,380 to 1500 minutes(23 to 25 hours). However, when a sample pe-riod is less than 1,380 minutes, the measuredconcentration (as determined by the col-lected PM2.5 mass divided by the actual sam-

pled air volume), multiplied by the actualnumber of minutes in the sample period anddivided by 1,440, may be used as if it were avalid concentration measurement for thespecific purpose of determining a violation ofthe NAAQS. This value assumes that thePM2.5 concentration is zero for the remainingportion of the sample period and thereforerepresents the minimum concentration thatcould have been measured for the full 24-hoursample period. Accordingly, if the value thuscalculated is high enough to be an exceed-ance, such an exceedance would be a valid

exceedance for the sample period. When re-ported to AIRS, this data value should re-ceive a special code to identify it as not to becommingled with normal concentrationmeasurements or used for other purposes.

4.0 Accuracy.

4.1 Because the size and volatility of theparticles making up ambient particulatematter vary over a wide range and the massconcentration of particles varies with par-ticle size, it is difficult to define the accu-racy of PM2.5 measurements in an absolutesense. The accuracy of PM2.5 measurementsis therefore defined in a relative sense, ref-erenced to measurements provided by thisreference method. Accordingly, accuracyshall be defined as the degree of agreementbetween a subject field PM2.5 sampler and acollocated PM2.5 reference method auditsampler operating simultaneously at themonitoring site location of the subject sam-pler and includes both random (precision)and systematic (bias) errors. The require-ments for this field sampler audit procedureare set forth in part 58, appendix A of thischapter.

4.2 Measurement system bias. Results of col-located measurements where the duplicatesampler is a reference method sampler areused to assess a portion of the measurementsystem bias according to the schedule andprocedure specified in part 58, appendix A ofthis chapter.

4.3 Audits with reference method samplers todetermine system accuracy and bias.

Accordingto the schedule and procedure specified inpart 58, appendix A of this chapter, a ref-erence method sampler is required to be lo-cated at each of selected PM2.5 SLAMS sitesas a duplicate sampler. The results from theprimary sampler and the duplicate referencemethod sampler are used to calculate accu-racy of the primary sampler on a quarterlybasis, bias of the primary sampler on an an-nual basis, and bias of a single reporting or-ganization on an annual basis. Reference 2 insection 13.0 of this appendix provides addi-tional information and guidance on thesereference method audits.

4.4 Flow rate accuracy and bias. Part 58, ap-pendix A of this chapter requires that theflow rate accuracy and bias of individualPM2.5 samplers used in SLAMS monitoringnetworks be assessed periodically via auditsof each sampler’s operational flow rate. Inaddition, part 58, appendix A of this chapterrequires that flow rate bias for each ref-erence and equivalent method operated byeach reporting organization be assessedquarterly and annually. Reference 2 in sec-tion 13.0 of this appendix provides additionalinformation and guidance on flow rate accu-racy audits and calculations for accuracyand bias.

5.0 Precision. A data quality objective of 10percent coefficient of variation or better has

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Environmental Protection Agency Pt. 50, App. L

been established for the operational preci-sion of PM2.5 monitoring data.

5.1 Tests to establish initial operationalprecision for each reference method samplerare specified as a part of the requirementsfor designation as a reference method under§ 53.58 of this chapter.

5.2 Measurement System Precision. Collo-cated sampler results, where the duplicatesampler is not a reference method samplerbut is a sampler of the same designatedmethod as the primary sampler, are used toassess measurement system precision ac-cording to the schedule and procedure speci-fied in part 58, appendix A of this chapter.Part 58, appendix A of this chapter requires

that these collocated sampler measurementsbe used to calculate quarterly and annualprecision estimates for each primary sam-pler and for each designated method em-ployed by each reporting organization. Ref-erence 2 in section 13.0 of this appendix pro-vides additional information and guidanceon this requirement.

6.0 Filter for PM 2.5 Sample Collection. Any fil-ter manufacturer or vendor who sells or of-fers to sell filters specifically identified foruse with this PM2.5 reference method shallcertify that the required number of filtersfrom each lot of filters offered for sale assuch have been tested as specified in this sec-tion 6.0 and meet all of the following designand performance specifications.

6.1 Size. Circular, 46.2 mm diameter ±0.25mm.

6.2 Medium. Polytetrafluoroethylene(PTFE Teflon), with integral support ring.

6.3 Support ring. Polymethylpentene (PMP)or equivalent inert material, 0.38 ±0.04 mmthick, outer diameter 46.2 mm ±0.25 mm, andwidth of 3.68 mm ( ±0.00, -0.51 mm).

6.4 Pore size. 2 µm as measured by ASTM F316–94.

6.5 Filter thickness. 30 to 50 µm.6.6 Maximum pressure drop (clean filter). 30

cm H2O column @ 16.67 L/min clean air flow.6.7 Maximum moisture pickup. Not more

than 10 µg weight increase after 24-hour ex-posure to air of 40 percent relative humidity,relative to weight after 24-hour exposure toair of 35 percent relative humidity.

6.8 Collection efficiency. Greater than 99.7percent, as measured by the DOP test (ASTMD 2986–91) with 0.3 µm particles at the sam-

pler’s operating face velocity.6.9 Filter weight stability. Filter weight lossshall be less than 20 µg, as measured in eachof the following two tests specified in sec-tions 6.9.1 and 6.9.2 of this appendix. The fol-lowing conditions apply to both of thesetests: Filter weight loss shall be the averagedifference between the initial and the finalfilter weights of a random sample of test fil-ters selected from each lot prior to sale. Thenumber of filters tested shall be not lessthan 0.1 percent of the filters of each manu-facturing lot, or 10 filters, whichever is

greater. The filters shall be weighed underlaboratory conditions and shall have had noair sample passed through them, i.e., filterblanks. Each test procedure must includeinitial conditioning and weighing, the test,and final conditioning and weighing. Condi-tioning and weighing shall be in accordancewith sections 8.0 through 8.2 of this appendixand general guidance provided in reference 2of section 13.0 of this appendix.

6.9.1 Test for loose, surface particle contami-nation. After the initial weighing, installeach test filter, in turn, in a filter cassette(Figures L–27, L–28, and L–29 of this appen-dix) and drop the cassette from a height of 25cm to a flat hard surface, such as a particle-

free wood bench. Repeat two times, for atotal of three drop tests for each test filter.Remove the test filter from the cassette andweigh the filter. The average change inweight must be less than 20 µg.

6.9.2 Test for temperature stability. Afterweighing each filter, place the test filters ina drying oven set at 40 °C ±2 °C for not lessthan 48 hours. Remove, condition, and re-weigh each test filter. The average change inweight must be less than 20 µg.

6.10 Alkalinity. Less than 25 microequiva-lents/gram of filter, as measured by the guid-ance given in reference 2 in section 13.0 ofthis appendix.

6.11 Supplemental requirements. Althoughnot required for determination of PM2.5 massconcentration under this reference method,additional specifications for the filter must

be developed by users who intend to subjectPM2.5 filter samples to subsequent chemicalanalysis. These supplemental specificationsinclude background chemical contaminationof the filter and any other filter parametersthat may be required by the method of chem-ical analysis. All such supplemental filterspecifications must be compatible with andsecondary to the primary filter specifica-tions given in this section 6.0 of this appen-dix.

7.0 PM 2.5 Sampler.7.1 Configuration. The sampler shall consist

of a sample air inlet, downtube, particle sizeseparator (impactor), filter holder assembly,air pump and flow rate control system, flowrate measurement device, ambient and filtertemperature monitoring system, barometricpressure measurement system, timer, out-

door environmental enclosure, and suitablemechanical, electrical, or electronic controlcapability to meet or exceed the design andfunctional performance as specified in thissection 7.0 of this appendix. The performancespecifications require that the sampler:

(a) Provide automatic control of samplevolumetric flow rate and other operationalparameters.

(b) Monitor these operational parametersas well as ambient temperature and pressure.

(c) Provide this information to the sampleroperator at the end of each sample period in



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digital form, as specified in table L–1 of sec-tion 7.4.19 of this appendix.

7.2 Nature of specifications. The PM2.5 sam-pler is specified by a combination of designand performance requirements. The sampleinlet, downtube, particle size discriminator,filter cassette, and the internal configura-tion of the filter holder assembly are speci-fied explicitly by design figures and associ-ated mechanical dimensions, tolerances, ma-terials, surface finishes, assembly instruc-tions, and other necessary specifications. Allother aspects of the sampler are specified byrequired operational function and perform-ance, and the design of these other aspects(including the design of the lower portion of

the filter holder assembly) is optional, sub-ject to acceptable operational performance.Test procedures to demonstrate compliancewith both the design and performance re-quirements are set forth in subpart E of part53 of this chapter.

7.3 Design specifications. Except as indicatedin this section 7.3 of this appendix, thesecomponents must be manufactured or repro-duced exactly as specified, in an ISO 9001-registered facility, with registration ini-tially approved and subsequently maintainedduring the period of manufacture. See§ 53.1(t) of this chapter for the definition ofan ISO-registered facility. Minor modifica-tions or variances to one or more compo-nents that clearly would not affect the aero-dynamic performance of the inlet, downtube,impactor, or filter cassette will be consid-

ered for specific approval. Any such proposedmodifications shall be described and sub-mitted to the EPA for specific individual ac-ceptability either as part of a reference orequivalent method application under part 53of this chapter or in writing in advance ofsuch an intended application under part 53 ofthis chapter.

7.3.1 Sample inlet assembly. The sample inletassembly, consisting of the inlet, downtube,and impactor shall be configured and assem-bled as indicated in Figure L–1 of this appen-dix and shall meet all associated require-ments. A portion of this assembly shall alsobe subject to the maximum overall samplerleak rate specification under section 7.4.6 ofthis appendix.

7.3.2 Inlet. The sample inlet shall be fab-ricated as indicated in Figures L–2 through

L–18 of this appendix and shall meet all asso-ciated requirements.7.3.3 Downtube. The downtube shall be fab-

ricated as indicated in Figure L–19 of this ap-pendix and shall meet all associated require-ments.

7.3.4 Particle size separator. The samplershall be configured with either one of thetwo alternative particle size separators de-scribed in this section 7.3.4. One separator isan impactor-type separator (WINS impactor)described in sections 7.3.4.1, 7.3.4.2, and 7.3.4.3of this appendix. The alternative separator is

a cyclone-type separator (VSCCTM) describedin section 7.3.4.4 of this appendix.

7.3.4.1 The impactor (particle size sepa-rator) shall be fabricated as indicated in Fig-ures L–20 through L–24 of this appendix andshall meet all associated requirements. Fol-lowing the manufacture and finishing of eachupper impactor housing (Figure L–21 of thisappendix), the dimension of the impactionjet must be verified by the manufacturerusing Class ZZ go/no-go plug gauges that aretraceable to NIST.

7.3.4.2 Impactor filter specifications:(a) Size. Circular, 35 to 37 mm diameter.(b) Medium. Borosilicate glass fiber, with-

out binder.

(c) Pore size. 1 to 1.5 micrometer, as meas-ured by ASTM F 316–80.

(d) Thickness. 300 to 500 micrometers.7.3.4.3 Impactor oil specifications:(a) Composition. Dioctyl sebacate (DOS),

single-compound diffusion oil.(b) Vapor pressure. Maximum 2×10¥8 mm

Hg at 25 °C.(c) Viscosity. 36 to 40 centistokes at 25 °C.(d) Density. 1.06 to 1.07 g/cm3 at 25 °C.(e) Quantity. 1 mL ±0.1 mL.7.3.4.4 The cyclone-type separator is iden-

tified as a BGI VSCCTM Very Sharp Cut Cy-clone particle size separator specified as partof EPA-designated equivalent methodEQPM–0202–142 (67 FR 15567, April 2, 2002) andas manufactured by BGI Incorporated, 58Guinan Street, Waltham, Massachusetts20451.

7.3.5 Filter holder assembly. The samplershall have a sample filter holder assembly toadapt and seal to the down tube and to holdand seal the specified filter, under section 6.0of this appendix, in the sample air stream ina horizontal position below the downtubesuch that the sample air passes downwardthrough the filter at a uniform face velocity.The upper portion of this assembly shall befabricated as indicated in Figures L–25 andL–26 of this appendix and shall accept andseal with the filter cassette, which shall befabricated as indicated in Figures L–27through L–29 of this appendix.

(a) The lower portion of the filter holderassembly shall be of a design and construc-tion that:

(1) Mates with the upper portion of the as-sembly to complete the filter holder assem-

bly,(2) Completes both the external air sealand the internal filter cassette seal suchthat all seals are reliable over repeated filterchangings, and

(3) Facilitates repeated changing of the fil-ter cassette by the sampler operator.

(b) Leak-test performance requirementsfor the filter holder assembly are included insection 7.4.6 of this appendix.

(c) If additional or multiple filters arestored in the sampler as part of an auto-matic sequential sample capability, all such



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filters, unless they are currently and di-rectly installed in a sampling channel orsampling configuration (either active or in-active), shall be covered or (preferably)sealed in such a way as to:

(1) Preclude significant exposure of the fil-ter to possible contamination or accumula-tion of dust, insects, or other material thatmay be present in the ambient air, sampler,or sampler ventilation air during storage pe-riods either before or after sampling; and

(2) To minimize loss of volatile or semi-volatile PM sample components during stor-age of the filter following the sample period.

7.3.6 Flow rate measurement adapter. A flowrate measurement adapter as specified in

Figure L–30 of this appendix shall be fur-nished with each sampler.

7.3.7 Surface finish. All internal surfaces ex-posed to sample air prior to the filter shallbe treated electrolytically in a sulfuric acidbath to produce a clear, uniform anodizedsurface finish of not less than 1000 mg/ft2 (1.08 mg/cm2) in accordance with militarystandard specification (mil. spec.) 8625F,Type II, Class 1 in reference 4 of section 13.0of this appendix. This anodic surface coatingshall not be dyed or pigmented. Followinganodization, the surfaces shall be sealed byimmersion in boiling deionized water for notless than 15 minutes. Section 53.51(d)(2) ofthis chapter should also be consulted.

7.3.8 Sampling height. The sampler shall beequipped with legs, a stand, or other meansto maintain the sampler in a stable, upright

position and such that the center of the sam-ple air entrance to the inlet, during samplecollection, is maintained in a horizontalplane and is 2.0 ±0.2 meters above the floor orother horizontal supporting surface. Suitablebolt holes, brackets, tie-downs, or othermeans should be provided to facilitate me-chanically securing the sample to the sup-porting surface to prevent toppling of thesampler due to wind.

7.4 Performance specifications.7.4.1 Sample flow rate. Proper operation of

the impactor requires that specific air ve-locities be maintained through the device.Therefore, the design sample air flow ratethrough the inlet shall be 16.67 L/min (1.000m3/hour) measured as actual volumetric flowrate at the temperature and pressure of thesample air entering the inlet.

7.4.2Sample air flow rate control system.

Thesampler shall have a sample air flow ratecontrol system which shall be capable of pro-viding a sample air volumetric flow ratewithin the specified range, under section7.4.1 of this appendix, for the specified filter,under section 6.0 of this appendix, at any at-mospheric conditions specified, under sec-tion 7.4.7 of this appendix, at a filter pressuredrop equal to that of a clean filter plus up to75 cm water column (55 mm Hg), and over thespecified range of supply line voltage, undersection 7.4.15.1 of this appendix. This flow

control system shall allow for operator ad-justment of the operational flow rate of thesampler over a range of at least ±15 percentof the flow rate specified in section 7.4.1 ofthis appendix.

7.4.3 Sample flow rate regulation. The sampleflow rate shall be regulated such that for thespecified filter, under section 6.0 of this ap-pendix, at any atmospheric conditions speci-fied, under section 7.4.7 of this appendix, at afilter pressure drop equal to that of a cleanfilter plus up to 75 cm water column (55 mmHg), and over the specified range of supplyline voltage, under section 7.4.15.1 of this ap-pendix, the flow rate is regulated as follows:

7.4.3.1 The volumetric flow rate, measured

or averaged over intervals of not more than5 minutes over a 24-hour period, shall notvary more than ±5 percent from the specified16.67 L/min flow rate over the entire sampleperiod.

7.4.3.2 The coefficient of variation (samplestandard deviation divided by the mean) ofthe flow rate, measured over a 24-hour pe-riod, shall not be greater than 2 percent.

7.4.3.3 The amplitude of short-term flowrate pulsations, such as may originate fromsome types of vacuum pumps, shall be at-tenuated such that they do not cause signifi-cant flow measurement error or affect thecollection of particles on the particle collec-tion filter.

7.4.4 Flow rate cut off. The sampler’s sampleair flow rate control system shall terminatesample collection and stop all sample flow

for the remainder of the sample period in theevent that the sample flow rate deviates bymore than 10 percent from the sampler de-sign flow rate specified in section 7.4.1 of thisappendix for more than 60 seconds. However,this sampler cut-off provision shall not applyduring periods when the sampler is inoper-ative due to a temporary power interruption,and the elapsed time of the inoperative pe-riod shall not be included in the total sampletime measured and reported by the sampler,under section 7.4.13 of this appendix.

7.4.5 Flow rate measurement.7.4.5.1 The sampler shall provide a means

to measure and indicate the instantaneoussample air flow rate, which shall be meas-ured as volumetric flow rate at the tempera-ture and pressure of the sample air enteringthe inlet, with an accuracy of ±2 percent.

The measured flow rate shall be available fordisplay to the sampler operator at any timein either sampling or standby modes, and themeasurement shall be updated at least every30 seconds. The sampler shall also provide asimple means by which the sampler operatorcan manually start the sample flow tempo-rarily during non-sampling modes of oper-ation, for the purpose of checking the sampleflow rate or the flow rate measurement sys-tem.

7.4.5.2 During each sample period, the sam-pler’s flow rate measurement system shall



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automatically monitor the sample volu-metric flow rate, obtaining flow rate meas-urements at intervals of not greater than 30seconds.

(a) Using these interval flow rate measure-ments, the sampler shall determine or cal-culate the following flow-related parameters,scaled in the specified engineering units:

(1) The instantaneous or interval-averageflow rate, in L/min.

(2) The value of the average sample flowrate for the sample period, in L/min.

(3) The value of the coefficient of variation(sample standard deviation divided by theaverage) of the sample flow rate for the sam-ple period, in percent.

(4) The occurrence of any time intervalduring the sample period in which the meas-ured sample flow rate exceeds a range of ±5percent of the average flow rate for the sam-ple period for more than 5 minutes, in whichcase a warning flag indicator shall be set.

(5) The value of the integrated total sam-ple volume for the sample period, in m3.

(b) Determination or calculation of thesevalues shall properly exclude periods whenthe sampler is inoperative due to temporaryinterruption of electrical power, under sec-tion 7.4.13 of this appendix, or flow rate cutoff, under section 7.4.4 of this appendix.

(c) These parameters shall be accessible tothe sampler operator as specified in table L–1 of section 7.4.19 of this appendix. In addi-tion, it is strongly encouraged that the flowrate for each 5-minute interval during the

sample period be available to the operatorfollowing the end of the sample period.

7.4.6 Leak test capability.7.4.6.1 External leakage. The sampler shall

include an external air leak-test capabilityconsisting of components, accessory hard-ware, operator interface controls, a writtenprocedure in the associated Operation/In-struction Manual, under section 7.4.18 of thisappendix, and all other necessary functionalcapability to permit and facilitate the sam-pler operator to conveniently carry out aleak test of the sampler at a field moni-toring site without additional equipment.The sampler components to be subjected tothis leak test include all components andtheir interconnections in which external airleakage would or could cause an error in thesampler’s measurement of the total volume

of sample air that passes through the samplefilter.(a) The suggested technique for the oper-

ator to use for this leak test is as follows:(1) Remove the sampler inlet and installs

the flow rate measurement adapter suppliedwith the sampler, under section 7.3.6 of thisappendix.

(2) Close the valve on the flow rate meas-urement adapter and use the sampler airpump to draw a partial vacuum in the sam-pler, including (at least) the impactor, filterholder assembly (filter in place), flow meas-

urement device, and interconnections be-tween these devices, of at least 55 mm Hg (75cm water column), measured at a locationdownstream of the filter holder assembly.

(3) Plug the flow system downstream ofthese components to isolate the componentsunder vacuum from the pump, such as with abuilt-in valve.

(4) Stop the pump.

(5) Measure the trapped vacuum in thesampler with a built-in pressure measuringdevice.

(6) (i) Measure the vacuum in the samplerwith the built-in pressure measuring deviceagain at a later time at least 10 minutes

after the first pressure measurement.(ii) CAUTION: Following completion of thetest, the adaptor valve should be openedslowly to limit the flow rate of air into thesampler. Excessive air flow rate may blowoil out of the impactor.

(7) Upon completion of the test, open theadaptor valve, remove the adaptor and plugs,and restore the sampler to the normal oper-ating configuration.

(b) The associated leak test procedureshall require that for successful passage ofthis test, the difference between the twopressure measurements shall not be greaterthan the number of mm of Hg specified forthe sampler by the manufacturer, based onthe actual internal volume of the sampler,that indicates a leak of less than 80 mL/min.

(c) Variations of the suggested technique

or an alternative external leak test tech-nique may be required for samplers whosedesign or configuration would make the sug-gested technique impossible or impractical.The specific proposed external leak test pro-cedure, or particularly an alternative leaktest technique, proposed for a particular can-didate sampler may be described and sub-mitted to the EPA for specific individual ac-ceptability either as part of a reference orequivalent method application under part 53of this chapter or in writing in advance ofsuch an intended application under part 53 ofthis chapter.

7.4.6.2 Internal, filter bypass leakage. Thesampler shall include an internal, filter by-pass leak-check capability consisting ofcomponents, accessory hardware, operatorinterface controls, a written procedure in theOperation/Instruction Manual, and all othernecessary functional capability to permitand facilitate the sampler operator to con-veniently carry out a test for internal filterbypass leakage in the sampler at a fieldmonitoring site without additional equip-ment. The purpose of the test is to determinethat any portion of the sample flow rate thatleaks past the sample filter without passingthrough the filter is insignificant relative tothe design flow rate for the sampler.

(a) The suggested technique for the oper-ator to use for this leak test is as follows:



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(1) Carry out an external leak test as pro-vided under section 7.4.6.1 of this appendixwhich indicates successful passage of theprescribed external leak test.

(2) Install a flow-impervious membranematerial in the filter cassette, either with orwithout a filter, as appropriate, which effec-tively prevents air flow through the filter.

(3) Use the sampler air pump to draw a par-tial vacuum in the sampler, downstream ofthe filter holder assembly, of at least 55 mmHg (75 cm water column).

(4) Plug the flow system downstream of thefilter holder to isolate the components undervacuum from the pump, such as with a built-in valve.

(5) Stop the pump.(6) Measure the trapped vacuum in the

sampler with a built-in pressure measuringdevice.

(7) Measure the vacuum in the samplerwith the built-in pressure measuring deviceagain at a later time at least 10 minutesafter the first pressure measurement.

(8) Remove the flow plug and membraneand restore the sampler to the normal oper-ating configuration.

(b) The associated leak test procedureshall require that for successful passage ofthis test, the difference between the twopressure measurements shall not be greaterthan the number of mm of Hg specified forthe sampler by the manufacturer, based onthe actual internal volume of the portion of

the sampler under vacuum, that indicates aleak of less than 80 mL/min.(c) Variations of the suggested technique

or an alternative internal, filter bypass leaktest technique may be required for samplerswhose design or configuration would makethe suggested technique impossible or im-practical. The specific proposed internal leaktest procedure, or particularly an alternativeinternal leak test technique proposed for aparticular candidate sampler may be de-scribed and submitted to the EPA for spe-cific individual acceptability either as partof a reference or equivalent method applica-tion under part 53 of this chapter or in writ-ing in advance of such intended applicationunder part 53 of this chapter.

7.4.7 Range of operational conditions. Thesampler is required to operate properly andmeet all requirements specified in this ap-pendix over the following operational ranges.

7.4.7.1 Ambient temperature. -30 to =45 °C(Note: Although for practical reasons, thetemperature range over which samplers arerequired to be tested under part 53 of thischapter is -20 to =40 °C, the sampler shall bedesigned to operate properly over this widertemperature range.).

7.4.7.2 Ambient relative humidity. 0 to 100percent.

7.4.7.3 Barometric pressure range. 600 to 800mm Hg.

7.4.8 Ambient temperature sensor. The sam-pler shall have capability to measure thetemperature of the ambient air surroundingthe sampler over the range of -30 to =45 °C,with a resolution of 0.1 °C and accuracy of±2.0 °C, referenced as described in reference 3in section 13.0 of this appendix, with andwithout maximum solar insolation.

7.4.8.1 The ambient temperature sensorshall be mounted external to the sampler en-closure and shall have a passive, naturallyventilated sun shield. The sensor shall be lo-cated such that the entire sun shield is atleast 5 cm above the horizontal plane of thesampler case or enclosure (disregarding theinlet and downtube) and external to the

vertical plane of the nearest side or protu-berance of the sampler case or enclosure.The maximum temperature measurementerror of the ambient temperature measure-ment system shall be less than 1.6 °C at 1 m/s wind speed and 1000 W/m2 solar radiationintensity.

7.4.8.2 The ambient temperature sensorshall be of such a design and mounted insuch a way as to facilitate its convenientdismounting and immersion in a liquid forcalibration and comparison to the filter tem-perature sensor, under section 7.4.11 of thisappendix.

7.4.8.3 This ambient temperature measure-ment shall be updated at least every 30 sec-onds during both sampling and standby (non-sampling) modes of operation. A visual indi-cation of the current (most recent) value of

the ambient temperature measurement, up-dated at least every 30 seconds, shall beavailable to the sampler operator duringboth sampling and standby (non-sampling)modes of operation, as specified in table L–1of section 7.4.19 of this appendix.

7.4.8.4 This ambient temperature measure-ment shall be used for the purpose of moni-toring filter temperature deviation from am-bient temperature, as required by section7.4.11 of this appendix, and may be used forpurposes of effecting filter temperature con-trol, under section 7.4.10 of this appendix, orcomputation of volumetric flow rate, undersections 7.4.1 to 7.4.5 of this appendix, if ap-propriate.

7.4.8.5 Following the end of each sample pe-riod, the sampler shall report the maximum,minimum, and average temperature for the

sample period, as specified in table L–1 ofsection 7.4.19 of this appendix.7.4.9 Ambient barometric sensor. The sampler

shall have capability to measure the baro-metric pressure of the air surrounding thesampler over a range of 600 to 800 mm Hg ref-erenced as described in reference 3 in section13.0 of this appendix; also see part 53, subpartE of this chapter. This barometric pressuremeasurement shall have a resolution of 5mm Hg and an accuracy of ±10 mm Hg andshall be updated at least every 30 seconds. Avisual indication of the value of the current



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(most recent) barometric pressure measure-ment, updated at least every 30 seconds,shall be available to the sampler operatorduring both sampling and standby (non-sam-pling) modes of operation, as specified intable L–1 of section 7.4.19 of this appendix.This barometric pressure measurement maybe used for purposes of computation of volu-metric flow rate, under sections 7.4.1 to 7.4.5of this appendix, if appropriate. Followingthe end of a sample period, the sampler shallreport the maximum, minimum, and meanbarometric pressures for the sample period,as specified in table L–1 of section 7.4.19 ofthis appendix.

7.4.10 Filter temperature control (sampling

and post-sampling). The sampler shall providea means to limit the temperature rise of thesample filter (all sample filters for sequen-tial samplers), from insolation and othersources, to no more 5 °C above the tempera-ture of the ambient air surrounding the sam-pler, during both sampling and post-sam-pling periods of operation. The post-sam-pling period is the non-sampling period be-tween the end of the active sampling periodand the time of retrieval of the sample filterby the sampler operator.

7.4.11 Filter temperature sensor(s).7.4.11.1 The sampler shall have the capa-

bility to monitor the temperature of thesample filter (all sample filters for sequen-tial samplers) over the range of -30 to =45 °Cduring both sampling and non-sampling peri-ods. While the exact location of this tem-

perature sensor is not explicitly specified,the filter temperature measurement systemmust demonstrate agreement, within 1 °C,with a test temperature sensor located with-in 1 cm of the center of the filter down-stream of the filter during both samplingand non-sampling modes, as specified in thefilter temperature measurement test de-scribed in part 53, subpart E of this chapter.This filter temperature measurement shallhave a resolution of 0.1 °C and accuracy of±1.0 °C, referenced as described in reference 3in section 13.0 of this appendix. This tem-perature sensor shall be of such a design andmounted in such a way as to facilitate itsreasonably convenient dismounting and im-mersion in a liquid for calibration and com-parison to the ambient temperature sensorunder section 7.4.8 of this appendix.

7.4.11.2 The filter temperature measure-ment shall be updated at least every 30 sec-onds during both sampling and standby (non-sampling) modes of operation. A visual indi-cation of the current (most recent) value ofthe filter temperature measurement, up-dated at least every 30 seconds, shall beavailable to the sampler operator duringboth sampling and standby (non-sampling)modes of operation, as specified in table L–1of section 7.4.19 of this appendix.

7.4.11.3 For sequential samplers, the tem-perature of each filter shall be measured in-

dividually unless it can be shown, as speci-fied in the filter temperature measurementtest described in §53.57 of this chapter, thatthe temperature of each filter can be rep-resented by fewer temperature sensors.

7.4.11.4 The sampler shall also provide awarning flag indicator following any occur-rence in which the filter temperature (anyfilter temperature for sequential samplers)exceeds the ambient temperature by morethan 5 °C for more than 30 consecutive min-utes during either the sampling or post-sam-pling periods of operation, as specified intable L–1 of section 7.4.19 of this appendix,under section 10.12 of this appendix, regard-ing sample validity when a warning flag oc-

curs. It is further recommended (not re-quired) that the sampler be capable of re-cording the maximum differential betweenthe measured filter temperature and the am-bient temperature and its time and date ofoccurrence during both sampling and post-sampling (non-sampling) modes of operationand providing for those data to be accessibleto the sampler operator following the end ofthe sample period, as suggested in table L–1of section 7.4.19 of this appendix.

7.4.12 Clock/timer system.(a) The sampler shall have a programmable

real-time clock timing/control system that:(1) Is capable of maintaining local time

and date, including year, month, day-of-month, hour, minute, and second to an accu-racy of ±1.0 minute per month.

(2) Provides a visual indication of the cur-

rent system time, including year, month,day-of-month, hour, and minute, updated atleast each minute, for operator verification.

(3) Provides appropriate operator controlsfor setting the correct local time and date.

(4) Is capable of starting the sample collec-tion period and sample air flow at a specific,operator-settable time and date, and stop-ping the sample air flow and terminating thesampler collection period 24 hours (1440 min-utes) later, or at a specific, operator-settabletime and date.

(b) These start and stop times shall bereadily settable by the sampler operator towithin ±1.0 minute. The system shall providea visual indication of the current start andstop time settings, readable to ±1.0 minute,for verification by the operator, and thestart and stop times shall also be available

via the data output port, as specified in tableL–1 of section 7.4.19 of this appendix. Uponexecution of a programmed sample periodstart, the sampler shall automatically resetall sample period information and warningflag indications pertaining to a previoussample period. Refer also to section 7.4.15.4of this appendix regarding retention of cur-rent date and time and programmed startand stop times during a temporary electricalpower interruption.

7.4.13 Sample time determination. The sam-pler shall be capable of determining the



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elapsed sample collection time for each PM2.5 sample, accurate to within ±1.0 minute,measured as the time between the start ofthe sampling period, under section 7.4.12 ofthis appendix and the termination of thesample period, under section 7.4.12 of this ap-pendix or section 7.4.4 of this appendix. Thiselapsed sample time shall not include peri-ods when the sampler is inoperative due to atemporary interruption of electrical power,under section 7.4.15.4 of this appendix. In theevent that the elapsed sample time deter-mined for the sample period is not within therange specified for the required sample pe-riod in section 3.3 of this appendix, the sam-pler shall set a warning flag indicator. The

date and time of the start of the sample pe-riod, the value of the elapsed sample time forthe sample period, and the flag indicator sta-tus shall be available to the sampler oper-ator following the end of the sample period,as specified in table L–1 of section 7.4.19 ofthis appendix.

7.4.14 Outdoor environmental enclosure. Thesampler shall have an outdoor enclosure (orenclosures) suitable to protect the filter andother non-weatherproof components of thesampler from precipitation, wind, dust, ex-tremes of temperature and humidity; to helpmaintain temperature control of the filter(or filters, for sequential samplers); and toprovide reasonable security for sampler com-ponents and settings.

7.4.15 Electrical power supply.7.4.15.1 The sampler shall be operable and

function as specified herein when operatedon an electrical power supply voltage of 105to 125 volts AC (RMS) at a frequency of 59 to61 Hz. Optional operation as specified at ad-ditional power supply voltages and/or fre-quencies shall not be precluded by this re-quirement.

7.4.15.2 The design and construction of thesampler shall comply with all applicable Na-tional Electrical Code and Underwriters Lab-oratories electrical safety requirements.

7.4.15.3 The design of all electrical andelectronic controls shall be such as to pro-vide reasonable resistance to interference ormalfunction from ordinary or typical levelsof stray electromagnetic fields (EMF) asmay be found at various monitoring sitesand from typical levels of electrical tran-sients or electronic noise as may often or oc-

casionally be present on various electricalpower lines.7.4.15.4 In the event of temporary loss of

electrical supply power to the sampler, thesampler shall not be required to sample orprovide other specified functions during suchloss of power, except that the internal clock/timer system shall maintain its local timeand date setting within ±1 minute per week,and the sampler shall retain all other timeand programmable settings and all data re-quired to be available to the sampler oper-ator following each sample period for at

least 7 days without electrical supply power.When electrical power is absent at the oper-ator-set time for starting a sample period oris interrupted during a sample period, thesampler shall automatically start or resumesampling when electrical power is restored,if such restoration of power occurs before theoperator-set stop time for the sample period.

7.4.15.5 The sampler shall have the capa-bility to record and retain a record of theyear, month, day-of-month, hour, andminute of the start of each power interrup-tion of more than 1 minute duration, up to 10such power interruptions per sample period.(More than 10 such power interruptions shallinvalidate the sample, except where an ex-

ceedance is measured, under section 3.3 ofthis appendix.) The sampler shall provide forthese power interruption data to be availableto the sampler operator following the end ofthe sample period, as specified in table L–1 ofsection 7.4.19 of this appendix.

7.4.16 Control devices and operator interface.The sampler shall have mechanical, elec-trical, or electronic controls, control de-vices, electrical or electronic circuits as nec-essary to provide the timing, flow rate meas-urement and control, temperature control,data storage and computation, operatorinterface, and other functions specified. Op-erator-accessible controls, data displays, andinterface devices shall be designed to be sim-ple, straightforward, reliable, and easy tolearn, read, and operate under field condi-tions. The sampler shall have provision for

operator input and storage of up to 64 char-acters of numeric (or alphanumeric) data forpurposes of site, sampler, and sample identi-fication. This information shall be availableto the sampler operator for verification andchange and for output via the data outputport along with other data following the endof a sample period, as specified in table L–1of section 7.4.19 of this appendix. All data re-quired to be available to the operator fol-lowing a sample collection period or ob-tained during standby mode in a post-sam-pling period shall be retained by the sampleruntil reset, either manually by the operatoror automatically by the sampler upon initi-ation of a new sample collection period.

7.4.17 Data output port requirement. Thesampler shall have a standard RS–232C dataoutput connection through which digital

data may be exported to an external datastorage or transmission device. All informa-tion which is required to be available at theend of each sample period shall be accessiblethrough this data output connection. The in-formation that shall be accessible thoughthis output port is summarized in table L–1of section 7.4.19 of this appendix. Since nospecific format for the output data is pro-vided, the sampler manufacturer or vendorshall make available to sampler purchasersappropriate computer software capable of re-ceiving exported sampler data and correctly



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translating the data into a standard spread-sheet format and optionally any other for-mats as may be useful to sampler users. Thisrequirement shall not preclude the samplerfrom offering other types of output connec-tions in addition to the required RS–232Cport.

7.4.18 Operation/instruction manual. Thesampler shall include an associated com-prehensive operation or instruction manual,as required by part 53 of this chapter, whichincludes detailed operating instructions onthe setup, operation, calibration, and main-tenance of the sampler. This manual shallprovide complete and detailed descriptions ofthe operational and calibration procedures

prescribed for field use of the sampler and allinstruments utilized as part of this referencemethod. The manual shall include adequatewarning of potential safety hazards that mayresult from normal use or malfunction of themethod and a description of necessary safetyprecautions. The manual shall also include aclear description of all procedures pertainingto installation, operation, periodic and cor-rective maintenance, and troubleshooting,and shall include parts identification dia-grams.

7.4.19 Data reporting requirements. The var-ious information that the sampler is re-quired to provide and how it is to be providedis summarized in the following table L–1.

TABLE L–1 TO APPENDIX L OF PART 50—SUMMARY OF INFORMATION TO BE PROVIDED BY THE SAMPLER

Information to beprovided

Appen-dix L

sectionref-

erence

Availability Format

Anytime 1 End ofperiod2

Visualdisplay3

Dataoutput4

Digitalreading5

Units

Flow rate, 30-sec-ond maximuminterval.

7.4.5.1 ✓ .................... ✓ * XX.X ................... L/min

Flow rate, aver-age for thesample period.

7.4.5.2 * ✓ * ✓ XX.X ................... L/min

Flow rate, CV, forsample period.

7.4.5.2 * ✓ * ✓ XX.X ................... %

Flow rate, 5-min.average out ofspec. (FLAG 6).

7.4.5.2 ✓ ✓ ✓ ✓■ On/Off

Sample volume,total.

7.4.5.2 * ✓ ✓ ✓ XX.X ................... m3

Temperature, am-bient, 30-sec-ond interval.

7.4.8 .... ✓ .................... ✓ .................... XX.X ................... °C

Temperature, am-bient, min.,max., averagefor the sampleperiod.

7.4.8 .... * ✓ ✓ ✓■ XX.X ................... °C

Baro. pressure,ambient, 30-second interval.

7.4.9 .... ✓ .................... ✓ .................... XXX .................... mm Hg

Baro. pressure,ambient, min.,max., averagefor the sampleperiod.

7.4.9 .... * ✓ ✓ ✓■ XXX .................... mm Hg

Filter temperature,30-second inter-val.

7.4.11 .. ✓ .................... ✓ .................... XX.X ................... °C

Filter temp. dif-

ferential, 30-second interval,out of spec.(FLAG6).

7.4.11 .. * ✓ ✓ ✓■ On/Off

Filter temp., max-imum differen-tial from ambi-ent, date, timeof occurrence.

7.4.11 .. * * * * X.X, YY/MM/DDHH.mm.

°C, Yr/Mon/DayHrs. min

Date and Time .... 7.4.12 .. ✓ .................... ✓ .................... YY/MM/DDHH.mm.

Yr/Mon/Day Hrs.min

Sample start andstop time set-tings.

7.4.12 .. ✓ ✓ ✓ ✓ YY/MM/DDHH.mm.

Yr/Mon/Day Hrs.min



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TABLE L–1 TO APPENDIX L OF PART 50—SUMMARY OF INFORMATION TO BE PROVIDED BY THE SAMPLER—Continued

Information to beprovided

Appen-dix L

sectionref-

erence

Availability Format

Anytime 1 End ofperiod2

Visualdisplay3

Dataoutput4

Digitalreading5

Units

Sample periodstart time.

7.4.12 .. .................... ✓ ✓ ✓ YY/MM/DDHH.mm.

Yr/Mon/Day Hrs.min

Elapsed sampletime.

7.4.13 .. * ✓ ✓ ✓ HH.mm ............... Hrs. min

Elapsed sampletime, out ofspec. (FLAG 6).

7.4.13 .. .................... ✓ ✓ ✓■ On/Off

Power interrup-tions ≤1 min.,

start time of first10.

7.4.15.5 * ✓ * ✓ 1HH.mm,2HH.mm, etc..

Hrs. min

User-entered in-formation, suchas sampler andsite identifica-tion.

7.4.16 .. ✓ ✓ ✓ ✓■ As entered.

✓ Provision of this information is required.* Provision of this information is optional. If information related to the entire sample period is optionally provided prior to the

end of the sample period, the value provided should be the value calculated for the portion of the sampler period completed upto the time the information is provided.

■ Indicates that this information is also required to be provided to the Air Quality System (AQS) data bank; see § 58.16 of thischapter. For ambient temperature and barometric pressure, only the average for the sample period must be reported.

1. Information is required to be available to the operator at any time the sampler is operating, whether sampling or not.2. Information relates to the entire sampler period and must be provided following the end of the sample period until reset

manually by the operator or automatically by the sampler upon the start of a new sample period.3. Information shall be available to the operator visually.4. Information is to be available as digital data at the sampler’s data output port specified in section 7.4.16 of this appendix fol-

lowing the end of the sample period until reset manually by the operator or automatically by the sampler upon the start of a newsample period.

5. Digital readings, both visual and data output, shall have not less than the number of significant digits and resolution speci-fied.

6. Flag warnings may be displayed to the operator by a single flag indicator or each flag may be displayed individually. Only aset (on) flag warning must be indicated; an off (unset) flag may be indicated by the absence of a flag warning. Sampler usersshould refer to section 10.12 of this appendix regarding the validity of samples for which the sampler provided an associated flagwarning.

8.0 Filter Weighing. See reference 2 in sec-tion 13.0 of this appendix, for additional,more detailed guidance.

8.1 Analytical balance. The analytical bal-ance used to weigh filters must be suitablefor weighing the type and size of filters spec-ified, under section 6.0 of this appendix, andhave a readability of ±1 µg. The balance shallbe calibrated as specified by the manufac-turer at installation and recalibrated imme-diately prior to each weighing session. Seereference 2 in section 13.0 of this appendix foradditional guidance.

8.2 Filter conditioning. All sample filtersused shall be conditioned immediately before

both the pre- and post-sampling weighings asspecified below. See reference 2 in section13.0 of this appendix for additional guidance.

8.2.1 Mean temperature. 20 - 23 °C.8.2.2 Temperature control. ±2 °C over 24

hours.

8.2.3 Mean humidity. Generally, 30–40 per-cent relative humidity; however, where itcan be shown that the mean ambient relativehumidity during sampling is less than 30 per-cent, conditioning is permissible at a meanrelative humidity within ±5 relative humid-

ity percent of the mean ambient relative hu-

midity during sampling, but not less than 20

percent.

8.2.4 Humidity control. ±5 relative humiditypercent over 24 hours.

8.2.5 Conditioning time. Not less than 24

hours.

8.3 Weighing procedure.

8.3.1 New filters should be placed in the

conditioning environment immediately upon

arrival and stored there until the pre-sam-pling weighing. See reference 2 in section 13.0

of this appendix for additional guidance.

8.3.2 The analytical balance shall be lo-

cated in the same controlled environment inwhich the filters are conditioned. The filters

shall be weighed immediately following the

conditioning period without intermediate ortransient exposure to other conditions or en-vironments.

8.3.3 Filters must be conditioned at thesame conditions (humidity within ±5 relativehumidity percent) before both the pre- andpost-sampling weighings.

8.3.4 Both the pre- and post-samplingweighings should be carried out on the same



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analytical balance, using an effective tech-nique to neutralize static charges on the fil-ter, under reference 2 in section 13.0 of thisappendix. If possible, both weighings shouldbe carried out by the same analyst.

8.3.5 The pre-sampling (tare) weighing shallbe within 30 days of the sampling period.

8.3.6 The post-sampling conditioning andweighing shall be completed within 240 hours(10 days) after the end of the sample period,unless the filter sample is maintained attemperatures below the average ambienttemperature during sampling (or 4 °C orbelow for average sampling temperaturesless than 4 °C) during the time between re-trieval from the sampler and the start of theconditioning, in which case the period shallnot exceed 30 days. Reference 2 in section13.0 of this appendix has additional guidanceon transport of cooled filters.

8.3.7 Filter blanks.8.3.7.1 New field blank filters shall be

weighed along with the pre-sampling (tare)weighing of each lot of PM2.5 filters. Theseblank filters shall be transported to the sam-pling site, installed in the sampler, retrievedfrom the sampler without sampling, and re-weighed as a quality control check.

8.3.7.2 New laboratory blank filters shall beweighed along with the pre-sampling (tare)weighing of each set of PM2.5 filters. Theselaboratory blank filters should remain in thelaboratory in protective containers duringthe field sampling and should be reweighedas a quality control check.

8.3.8 Additional guidance for proper filterweighing and related quality assurance ac-tivities is provided in reference 2 in section13.0 of this appendix.

9.0 Calibration. Reference 2 in section 13.0 ofthis appendix contains additional guidance.

9.1 General requirements.9.1.1 Multipoint calibration and single-

point verification of the sampler’s flow ratemeasurement device must be performed peri-odically to establish and maintaintraceability of subsequent flow measure-ments to a flow rate standard.

9.1.2 An authoritative flow rate standardshall be used for calibrating or verifying thesampler’s flow rate measurement device withan accuracy of ±2 percent. The flow ratestandard shall be a separate, stand-alone de-

vice designed to connect to the flow ratemeasurement adapter, Figure L–30 of this ap-pendix. This flow rate standard must haveits own certification and be traceable to aNational Institute of Standards and Tech-nology (NIST) primary standard for volumeor flow rate. If adjustments to the sampler’sflow rate measurement system calibrationare to be made in conjunction with an auditof the sampler’s flow measurement system,such adjustments shall be made followingthe audit. Reference 2 in section 13.0 of thisappendix contains additional guidance.

9.1.3 The sampler’s flow rate measurementdevice shall be re-calibrated afterelectromechanical maintenance or transportof the sampler.

9.2 Flow rate calibration/verification proce-dure.

9.2.1 PM2.5 samplers may employ varioustypes of flow control and flow measurementdevices. The specific procedure used for cali-bration or verification of the flow rate meas-urement device will vary depending on thetype of flow rate controller and flow ratemeasurement employed. Calibration shall bein terms of actual ambient volumetric flowrates (Qa), measured at the sampler’s inletdowntube. The generic procedure given hereserves to illustrate the general steps in-volved in the calibration of a PM2.5 sampler.The sampler operation/instruction manualrequired under section 7.4.18 of this appendixand the Quality Assurance Handbook in ref-erence 2 in section 13.0 of this appendix pro-vide more specific and detailed guidance forcalibration.

9.2.2 The flow rate standard used for flowrate calibration shall have its own certifi-cation and be traceable to a NIST primarystandard for volume or flow rate. A calibra-tion relationship for the flow rate standard,e.g., an equation, curve, or family of curvesrelating actual flow rate (Qa) to the flow rateindicator reading, shall be established that isaccurate to within 2 percent over the ex-pected range of ambient temperatures andpressures at which the flow rate standardmay be used. The flow rate standard must bere-calibrated or re-verified at least annually.

9.2.3 The sampler flow rate measurementdevice shall be calibrated or verified by re-moving the sampler inlet and connecting theflow rate standard to the sampler’s downtubein accordance with the operation/instructionmanual, such that the flow rate standard ac-curately measures the sampler’s flow rate.The sampler operator shall first carry out asampler leak check and confirm that thesampler passes the leak test and then verifythat no leaks exist between the flow ratestandard and the sampler.

9.2.4 The calibration relationship betweenthe flow rate (in actual L/min) indicated bythe flow rate standard and by the sampler’sflow rate measurement device shall be estab-

lished or verified in accordance with thesampler operation/instruction manual. Tem-perature and pressure corrections to the flowrate indicated by the flow rate standard maybe required for certain types of flow ratestandards. Calibration of the sampler’s flowrate measurement device shall consist of atleast three separate flow rate measurements(multipoint calibration) evenly spaced with-in the range of -10 percent to =10 percent ofthe sampler’s operational flow rate, section7.4.1 of this appendix. Verification of thesampler’s flow rate shall consist of one flow



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rate measurement at the sampler’s oper-ational flow rate. The sampler operation/in-struction manual and reference 2 in section13.0 of this appendix provide additional guid-ance.

9.2.5 If during a flow rate verification thereading of the sampler’s flow rate indicatoror measurement device differs by ±4 percentor more from the flow rate measured by theflow rate standard, a new multipoint calibra-tion shall be performed and the flow rateverification must then be repeated.

9.2.6 Following the calibration orverification, the flow rate standard shall beremoved from the sampler and the samplerinlet shall be reinstalled. Then the sampler’s

normal operating flow rate (in L/min) shallbe determined with a clean filter in place. Ifthe flow rate indicated by the sampler differsby ±2 percent or more from the required sam-pler flow rate, the sampler flow rate must beadjusted to the required flow rate, under sec-tion 7.4.1 of this appendix.

9.3 Periodic calibration or verification ofthe calibration of the sampler’s ambienttemperature, filter temperature, and baro-metric pressure measurement systems is alsorequired. Reference 3 of section 13.0 of thisappendix contains additional guidance.

10.0 PM 2.5 Measurement Procedure. The de-tailed procedure for obtaining valid PM2.5 measurements with each specific samplerdesignated as part of a reference method forPM2.5 under part 53 of this chapter shall beprovided in the sampler-specific operation or

instruction manual required by section 7.4.18of this appendix. Supplemental guidance isprovided in section 2.12 of the Quality Assur-ance Handbook listed in reference 2 in sec-tion 13.0 of this appendix. The generic proce-dure given here serves to illustrate the gen-eral steps involved in the PM2.5 sample col-lection and measurement, using a PM2.5 ref-erence method sampler.

10.1 The sampler shall be set up, calibrated,and operated in accordance with the specific,detailed guidance provided in the specificsampler’s operation or instruction manualand in accordance with a specific quality as-surance program developed and establishedby the user, based on applicable supple-mentary guidance provided in reference 2 insection 13.0 of this appendix.

10.2 Each new sample filter shall be in-

spected for correct type and size and for pin-holes, particles, and other imperfections. Un-acceptable filters should be discarded. Aunique identification number shall be as-signed to each filter, and an informationrecord shall be established for each filter. Ifthe filter identification number is not orcannot be marked directly on the filter, al-ternative means, such as a number-identifiedstorage container, must be established tomaintain positive filter identification.

10.3 Each filter shall be conditioned in theconditioning environment in accordance

with the requirements specified in section 8.2of this appendix.

10.4 Following conditioning, each filtershall be weighed in accordance with the re-quirements specified in section 8.0 of this ap-pendix and the presampling weight recordedwith the filter identification number.

10.5 A numbered and preweighed filter shallbe installed in the sampler following the in-structions provided in the sampler operationor instruction manual.

10.6 The sampler shall be checked and pre-pared for sample collection in accordancewith instructions provided in the sampler op-eration or instruction manual and with the

specific quality assurance program estab-lished for the sampler by the user.10.7 The sampler’s timer shall be set to

start the sample collection at the beginningof the desired sample period and stop thesample collection 24 hours later.

10.8 Information related to the sample col-lection (site location or identification num-ber, sample date, filter identification num-ber, and sampler model and serial number)shall be recorded and, if appropriate, enteredinto the sampler.

10.9 The sampler shall be allowed to collectthe PM2.5 sample during the set 24-hour timeperiod.

10.10 Within 177 hours (7 days, 9 hours) ofthe end of the sample collection period, thefilter, while still contained in the filter cas-sette, shall be carefully removed from the

sampler, following the procedure provided inthe sampler operation or instruction manualand the quality assurance program, andplaced in a protective container. The protec-tive container shall contain no loose mate-rial that could be transferred to the filter.The protective container shall hold the filtercassette securely such that the cover shallnot come in contact with the filter’s sur-faces. Reference 2 in section 13.0 of this ap-pendix contains additional information.

10.11 The total sample volume in actual m3 for the sampling period and the elapsed sam-ple time shall be obtained from the samplerand recorded in accordance with the instruc-tions provided in the sampler operation orinstruction manual. All sampler warningflag indications and other information re-quired by the local quality assurance pro-gram shall also be recorded.

10.12 All factors related to the validity orrepresentativeness of the sample, such assampler tampering or malfunctions, unusualmeteorological conditions, construction ac-tivity, fires or dust storms, etc. shall be re-corded as required by the local quality assur-ance program. The occurrence of a flag warn-ing during a sample period shall not nec-essarily indicate an invalid sample but rath-er shall indicate the need for specific reviewof the QC data by a quality assurance officerto determine sample validity.



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10.13 After retrieval from the sampler, theexposed filter containing the PM2.5 sampleshould be transported to the filter condi-tioning environment as soon as possible,ideally to arrive at the conditioning environ-ment within 24 hours for conditioning andsubsequent weighing. During the period be-tween filter retrieval from the sampler andthe start of the conditioning, the filter shallbe maintained as cool as practical and con-tinuously protected from exposure to tem-peratures over 25 °C to protect the integrityof the sample and minimize loss of volatilecomponents during transport and storage.See section 8.3.6 of this appendix regardingtime limits for completing the post-sampling

weighing. See reference 2 in section 13.0 ofthis appendix for additional guidance ontransporting filter samplers to the condi-tioning and weighing laboratory.

10.14. The exposed filter containing thePM2.5 sample shall be re-conditioned in theconditioning environment in accordancewith the requirements specified in section 8.2of this appendix.

10.15. The filter shall be reweighed imme-diately after conditioning in accordancewith the requirements specified in section 8.0of this appendix, and the postsamplingweight shall be recorded with the filter iden-tification number.

10.16 The PM2.5 concentration shall be cal-culated as specified in section 12.0 of this ap-pendix.

11.0 Sampler Maintenance. The sampler

shall be maintained as described by the sam-pler’s manufacturer in the sampler-specificoperation or instruction manual requiredunder section 7.4.18 of this appendix and inaccordance with the specific quality assur-ance program developed and established bythe user based on applicable supplementaryguidance provided in reference 2 in section13.0 of this appendix.

12.0 Calculations12.1 (a) The PM2.5 concentration is cal-

culated as:

PM2.5 = (Wf ¥Wi)/Va

where:

PM2.5 = mass concentration of PM2.5, µg/m3;Wf , Wi = final and initial weights, respec-

tively, of the filter used to collect thePM2.5 particle sample, µg;

Va = total air volume sampled in actual vol-ume units, as provided by the sampler, m3.

NOTE: Total sample time must be between1,380 and 1,500 minutes (23 and 25 hrs) for afully valid PM2.5 sample; however, see alsosection 3.3 of this appendix.

13.0 References.

1. Quality Assurance Handbook for Air Pol-

lution Measurement Systems, Volume I,Principles. EPA/600/R–94/038a, April 1994.Available from CERI, ORD Publications,U.S. Environmental Protection Agency, 26West Martin Luther King Drive, Cincinnati,Ohio 45268.

2. Quality Assurance Guidance Document2.12. Monitoring PM2.5 in Ambient Air UsingDesignated Reference or Class I EquivalentMethods. U.S. EPA, National Exposure Re-search Laboratory. Research Triangle Park,NC, November 1988 or later edition. Cur-rently available at: http://www.epa.gov/ttn/amtic/pmqainf.html.

3. Quality Assurance Handbook for Air Pol-lution Measurement Systems, Volume IV:Meteorological Measurements, (Revised Edi-tion) EPA/600/R–94/038d, March, 1995. Avail-able from CERI, ORD Publications, U.S. En-vironmental Protection Agency, 26 WestMartin Luther King Drive, Cincinnati, Ohio45268.

4. Military standard specification (mil.spec.) 8625F, Type II, Class 1 as listed in De-partment of Defense Index of Specificationsand Standards (DODISS), available fromDODSSP-Customer Service, StandardizationDocuments Order Desk, 700 Robbins Avenue,Building 4D, Philadelphia, PA 1911–5094.

14.0 Figures L–1 through L–30 to Appendix L.



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[62 FR 38714, July 18, 1997, as amended at 64 FR 19719, Apr. 22, 1999; 71 FR 61226, Oct. 17, 2006]