1、Designation: D 6877 03 (Reapproved 2008)Standard Test Method forMonitoring Diesel Particulate Exhaust in the Workplace1This standard is issued under the fixed designation D 6877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers determination of organic andelemental carbon in the particulate fraction of diesel eng
3、ineexhaust, hereafter referred to as diesel particulate matter(DPM). Samples of workplace atmospheres are collected onquartz-fiber filters. The method also is suitable for other typesof carbonaceous aerosols, but it is not appropriate for samplingvolatile or semi-volatile components. These component
4、s re-quire sorbents for efficient collection.NOTE 1Sample collection and handling procedures for environmentalsamples differ from occupational samples. This standard addresses occu-pational monitoring of DPM in workplaces where diesel-powered equip-ment is used.1.2 The method is based on a thermal-o
5、ptical technique (1,2)2. Speciation of organic and elemental carbon is achievedthrough temperature and atmosphere control, and an opticalfeature that corrects for sample charring.1.3 A portion of a 37-mm, quartz-fiber filter sample isanalyzed. Results for the portion are used to calculate the totalm
6、ass of organic and elemental carbon on the filter. The portionmust be representative of the entire filter deposit. If the depositis uneven, two or more representative portions should beanalyzed for an average. Open-faced cassettes give evendeposits but are often not practical. Closed-face cassettes
7、giveequivalent results if other dusts are absent. Other samplers maybe required, depending on the sampling environment (2-5).1.4 The calculated limit of detection (LOD) depends on thelevel of contamination of the media blanks (5). A LOD ofapproximately 0.2 g carbon per cm2of filter was estimatedwhen
8、 analyzing a sucrose standard solution applied to filterportions cleaned immediately before analysis. LODs based onmedia blanks stored after cleaning are usually higher. LODsbased on a set of media blanks from a commercial laboratorywere OC = 1.2 g/cm2, EC = 0.4 g/cm2, and TC = 1.3 g/cm2,where OC, E
9、C, and TC refer to organic, elemental, and totalcarbon, respectively.1.5 OC-EC methods are operational, which means theanalytical procedure defines the analyte. The test method offersgreater selectivity and precision than thermal techniques thatdo not correct for charring of organic components. The
10、analysismethod is simple and relatively quick (about 15 min). Theanalysis and data reduction are automated, and the instrumentis programmable (different methods can be saved as methodsfor other applications).1.6 A method (5040) for DPM based on thermal-opticalanalysis has been published by the Natio
11、nal Institute forOccupational Safety and Health (NIOSH). Method updates (3,4) have been published since its initial (1996) publication in theNIOSH Manual of Analytical Methods (NMAM). Both OC andEC are determined by NMAM 5040. An EC exposure markerwas recommended because EC is a more selective measu
12、re ofexposure.Acomprehensive review of the method and rationalefor selection of an EC marker are provided in a recent Chapterof NMAM (5).1.7 The thermal-optical instrument required for the analysisis manufactured by a private laboratory.3As with most instru-mentation, design improvements continue to
13、 be made. Differ-ent laboratories may be using different instrument models.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determin
14、e the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in 7.1.5, 8.3, and 12.12.2.2. Referenced Documents2.1 ASTM Standards:4D 1356 Terminology Relating to Sampling and Analysis ofAtmospheres1This test method is under the jurisdiction of ASTM Commit
15、tee D22 on AirQuality and is the direct responsibility of Subcommittee D22.04 on Workplace AirQuality.Current edition approved Aug. 1, 2008. Published September 2008. Originallyapproved in 2003. Last previous edition approved in 2003 as D 6877 03.2The boldface numbers in parentheses refer to referen
16、ces at the end of this testmethod.3The carbon analyzer used in the development and performance evaluation ofthis test method was manufactured by Sunset Laboratory, 2017 19thAvenue, ForestGrove, Oregon 97116, which is the sole source of supply of the instrument knownto the committee at this time. If
17、you are aware of alternative suppliers, pleaseprovide this information to ASTM Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee which youmay attend.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cu
18、stomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3. Terminology3.1 Definitions:3.2
19、 For definitions of terms used in this practice, refer toTerminology D 1356.3.3 limit of detection, LODA value for which exceedenceby measured mass indicates the presence of a substance atgiven false-positive rate: 3 3 estimated standard deviation ofestimated mass.3.4 Definitions of Terms Specific t
20、o This Standard:3.4.1 organic carbon (OC)Carbon volatilized in heliumwhile heating a quartz-fiber filter sample to 870C. Includescarbonates, if present, unless quantified separately. Also in-cludes char formed during pyrolysis of some materials.3.4.2 elemental carbon (EC)Excluding char, light-absorb
21、ing carbon that is not removed from a filter sampleheated to 870C in an inert atmosphere.3.4.3 total carbon (TC)Sum of organic and elementalcarbon.3.4.4 thermogramDigitized output signal of thermal-optical instrument. Shows detector and filter transmittancesignals at different temperatures in nonoxi
22、dizing and oxidizingatmospheres.3.5 Symbols and Abbreviations:3.5.1 DPMdiesel particulate matter3.5.2 LOD (g/cm2)limit of detection: 3 3 sw3.5.3 sw(g/cm2)estimate of sw3.5.4 sw(g/cm2)standard deviation in collected massloading determination3.5.5 OC, EC, TC (g/cm2or g)organic, elemental, andtotal car
23、bon3.5.6 RSDrelative standard deviation3.5.7 V (L)sampled volume3.5.8 Wb(g)field blank filters EC mass reading3.5.9 WEC(g)active filters EC mass reading4. Summary of Test Method4.1 The thermal-optical analyzer has been described previ-ously (1-5). Design improvements have been made over time,but the
24、 operation principle remains unchanged. OC-EC quan-tification is accomplished through temperature and atmospherecontrol. In addition, the analyzer is equipped with an opticalfeature that corrects for the char formed during the analysis ofsome materials. Optical correction is made with a pulsed diode
25、laser and photodetector that permit continuous monitoring ofthe filter transmittance.4.2 The main instrument components are illustrated in Fig.1. The instrument output, called a thermogram, is shown inFig. 2. For analysis, a known area (normally 1.5 cm2)ofthequartz-fiber filter sample is removed wit
26、h a sharp metal punch.Quartz-fiber filters are required because temperatures in excessof 850C are employed. The portion is inserted into the sampleoven, and the oven is tightly sealed. The analysis proceeds ininert and oxidizing atmospheres. First, OC (and carbonate, ifpresent) is removed in helium
27、as the temperature is stepped toa preset maximum (about 870C in NMAM 5040). Evolvedcarbon is catalytically oxidized to CO2in a bed of granularMnO2. The CO2is then reduced to CH4in a Ni/firebrickmethanator, and CH4is quantified by a FID. Next, the sampleoven temperature is lowered, an oxygen-helium m
28、ix (2 %oxygen after dilution of the 10 % oxygen in helium supply) isintroduced, and the temperature is increased to 900C (orhigher) to remove the residual carbon. At the end of eachanalysis, calibration is made through automatic injection of afixed volume of methane.4.3 Some samples contain componen
29、ts (for example, ciga-rette and wood smokes) that carbonize (convert to carbon) orchar in helium during the first part of the analysis. Like ECinitially present in the sample, char strongly absorbs light,particularly in the red/infrared region. The char formed throughpyrolysis (thermal decomposition
30、) of these components causesthe filter transmittance to decrease. Charring can begin at300C; the process may continue until the maximum tempera-ture is reached. After OC removal, an oxygen-helium mix isintroduced to effect combustion of residual carbon, whichincludes char and any EC originally prese
31、nt. As oxygen entersthe oven, light-absorbing carbon is oxidized and a concurrentFIG. 1 Schematic of Thermal-Optical Instrument (V = valve) for Determination of Organic and Elemental Carbon in DPM and OtherCarbonaceous Aerosols.D 6877 03 (2008)2increase in filter transmittance occurs. The split (ver
32、tical lineprior to EC peak in Fig. 2) between OC and EC is assignedwhen the initial (baseline) value of the filter transmittance isreached. All carbon removed before the OC-EC split isconsidered organic; that removed after the split is consideredelemental. If no char is formed, the split is assigned
33、 prior toremoval of EC. Ordinarily, the split is assigned in the oxidativemode of the analysis.4.4 Occasionally, original EC (as opposed to char) is lostwith the fourth temperature step in helium. Loss of EC inhelium is uncommon, but sometimes occurs, possibly due tooxidants in the sample. The OC-EC
34、 split is automaticallyassigned earlier (in helium) in these cases (5).4.5 OC and EC results are reported in units g per cm2offilter deposit. The total OC and EC on the filter are calculatedby multiplying the reported values by the deposit area (slightlyless than the filter area). A homogeneous depo
35、sit is assumed.The TC in the sample is the sum of OC and EC. If carbonateis present, the carbon in it is quantified as OC unless correctionis made. Additional details about carbonates are given in afollowing section.5. Significance and Use5.1 The test method supports proposed, occupational expo-sure
36、 standards (6, 7) for DPM. In the United States alone, overa million workers are occupationally exposed (8). An exposurestandard for mines is especially important because minersexposures are often quite high. NIOSH (8), the InternationalAgency for Research on Cancer (9) (IARC), the World HealthOrgan
37、ization (10) (WHO), the California Environmental Pro-tection Agency (11), the U.S. Environmental ProtectionAgency (12) (EPA), and the National Toxicology Program (13)have reviewed the animal and human evidence. All haveclassified diesel exhaust as a probable human carcinogen orsimilar designation.5.
38、2 The test method provides a measure of occupationalexposure to DPM. Previous studies have produced equivocalresults because exposure data are lacking. Given the economicand public health impact of epidemiological studies, accuraterisk assessment is critical. An ongoing NIOSH/NCI study ofminers expo
39、sed to diesel exhaust should provide a morequantitative estimate of the lung cancer risk. The test methodwas used for exposure monitoring. Since publication (in 1996)as NMAM 5040, the method has been routinely used foroccupational monitoring (5).5.3 The test method supports a proposed EPA air standa
40、rdfor fine particulate carbon. Recent studies indicate a positiveassociation between airborne levels of fine particles andrespiratory illness and mortality (14-22). The test method andothers have been used for EPA air monitoring networks and airpollution studies. Because different methods produce di
41、fferentresults, method standardization is essential for regulatorycompliance determinations and valid comparisons of interlabo-ratory data.NOTE 1PC is pyrolytically generated carbon (char). Final peak is methane calibration peak. Carbon sources: pulverized beet pulp, rock dust(carbonate), and diesel
42、 particulate.NOTE 2In the comparative test reported by Birch (28), participants used different maximum temperatures in helium (5). The actual maximum rangedfrom about 850-900C. NMAM 5040 specifies 870C, which is near the middle of the range.FIG. 2 Thermogram for Filter Sample Containing OC, Carbonat
43、e (CC), and EC.D 6877 03 (2008)35.4 The test method is being applied for emission-controltesting.6. Interferences6.1 EC is a more selective marker of occupational exposurethan other measures of DPM (for example, particulate mass,total carbon). As defined by the test method, EC is the carbondetermine
44、d during the second stage of the analysis (afterpyrolysis correction). If the sample contains no pyrolyzablematerial, all carbon evolved during this stage is consideredelemental. Inorganic dusts, carbonates, and wood and cigarettesmokes ordinarily do not interfere in the EC determination(2-5). OC ca
45、n be contributed by smokes, fumes and othersources.6.2 If high levels of other dusts are present, a size classifier(for example, impactor, or cyclone, or both) should be used. Ifthe dust is carbonaceous, a size classifier provides a moreselective measure of the diesel-source OC. It also provides abe
46、tter measure of the diesel-source EC if the dust contains EC(for example, carbon black, coal), which is less common. Afinely ground sample of the bulk material can be analyzed todetermine whether a dust poses potential interference. Depend-ing on the dust concentration, size distribution, and target
47、analyte (EC or TC), an impactor/cyclone may required. Addi-tional details can be found elsewhere (5). Some OC interfer-ences cannot be excluded on the basis of size (for example,cigarette smoke and other combustion aerosols, condensationaerosol, fumes).6.3 In metal and nonmetal mines, the Mine Safet
48、y andHealth Administration (MSHA) recommends use of a special-ized impactor (with cyclone) to minimize collection of carbon-ates and other carbonaceous dusts (7).6.4 For measurement of diesel-source EC in coal mines, animpactor with sub-micrometer cutpoint (7, 23, 24) must beused to minimize collect
49、ion of coal dust. Only low levels of ECwere found in non-dieselized coal mines when an impactorwith a sub-micrometer cutpoint was used (25).6.5 Environmental samples usually contain little (if any)carbonate. Levels in some occupational settings are quite high.Depending on the carbonate type, a carbonate-subtracted valuefor OC (and TC) can be obtained through acidification of thesample or separate integration of the carbonate peak (see12.12).7. Apparatus7.1 The main components of the thermal-optical analyzerused in the test method are illustr
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1