1、Designation: D6877 03 (Reapproved 2008)D6877 13Standard Test Method forMonitoring Diesel Particulate Exhaust in the Workplace1This standard is issued under the fixed designation D6877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the 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 and elemental carbon (OC and EC) in the particulate fra
3、ction of dieselengine exhaust, hereafter referred to as diesel particulate matter (DPM ). Samples of workplace atmospheres are collected onquartz-fiber filters.The method also is suitable for other types of carbonaceous aerosols, but it aerosols and has been widely appliedto environmental monitoring
4、. It is not appropriate for sampling volatile or semi-volatile components. These components requiresorbents for efficient collection.NOTE 1Sample collection and handling procedures for environmental samples differ from occupational samples.This standard addresses occupationalmonitoring of DPM in wor
5、kplaces where diesel-powered equipment is used.1.2 The method is based on a thermal-optical technique (1, 2)2. Speciation of organicOC and elementalEC carbon is achievedthrough temperature and atmosphere control, and an optical feature that corrects for sample charring.charring (carbonization).1.3 A
6、 portion of a 37-mm, quartz-fiber filter sample is analyzed. Results for the portion are used to calculate the total mass oforganicOC and elementalEC carbon on the filter. The portion must be representative of the entire filter deposit. If the deposit isuneven, two or more representative portions sh
7、ould be analyzed for an average. Alternatively, the entire filter can be analyzed, inmultiple portions, to determine the total mass. Open-faced cassettes give even deposits but are often may not practical. Closed-facecassettes give equivalent results be practical. At 2 L/min, closed-face cassettes g
8、enerally give results equivalent to open-facecassettes if other dusts are absent. Higher flow rates may be employed, but closed-faced cassettes operated at higher flow rates (forexample, 5 L/min) sometimes have uneven deposits due to particle impaction at the center of the filter. Other samplers may
9、 berequired, depending on the sampling environment (2-5).1.4 The calculated limit of detection (LOD) depends on the level of contamination of the media blanks (5). A LOD ofapproximately 0.2 g carbon per cm2 of filter was estimated when analyzing a sucrose standard solution applied to filter portions
10、cleaned immediately before analysis. LODs based on media blanks stored after cleaning are usually higher. LODs based on a setof media blanks from a analyzed over a six month period at a commercial laboratory were OC = 1.2 g/cm2, EC = 0.4 g/cm2,and TC = 1.3 g/cm2, where OC,TCEC, and refers to total c
11、arbon (TC refer= OC + ECto organic, elemental, ). In practice, the LODestimate provided by a laboratory is based on results for a set of media blanks submitted with the samples. To reduce blankvariability (due to lack of loading), a manual OC-EC split is assigned at the time when oxygen is introduce
12、d. With manual splits,the SD for media blanks is typically about 0.02-0.03 g EC/cm2, giving LODs (3 SD blank) from about 0.06-0.09 g EC/cm2andtotal carbon, respectively. . The corresponding air concentration depends on the deposit area (filter size) and air volume.1.5 OC-EC methods are operational,
13、which means the analytical procedure defines the analyte. The test method offers greaterselectivity and precision than thermal techniques that do not correct for charring of organic components. The analysis method issimple and relatively quick (about 15 min). The analysis and data reduction are auto
14、mated, and the instrument is programmable(different methods can be saved as methods for other applications).1.6 A method (5040) for DPM based on thermal-optical analysis has been published by the National Institute for OccupationalSafety and Health (NIOSH). Method updates (3,4) have been published s
15、ince its initial (1996) publication in the NIOSH Manualof Analytical Methods (NMAM). Both OC and EC are determined by NMAM 5040. An EC exposure marker (for DPM) wasrecommended because EC is a more selective measure of exposure. A comprehensive review of the method and rationale forselection of an EC
16、 marker are provided in a recent Chapter of NMAM (5).1 This test method is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved Aug. 1, 2008Oct. 1, 2013. Published September 2008October 20
17、13. Originally approved in 2003. Last previous edition approved in 20032008as D6877 03.D6877 03 (2008). DOI: 10.1520/D6877-03R08.10.1520/D6877-13.2 The boldface numbers in parentheses refer to references at the end of this test method.This document is not an ASTM standard and is intended only to pro
18、vide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the
19、 standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.7 The thermal-optical instrument required for the analysis is manufactured by a private laboratory.3 As with mo
20、stinstrumentation, design improvements continue to be made. Different laboratories may be using different instrument models.1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.9 This standard does not purport to address all
21、of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements are given in 7.1.5, 8.3, and 12.
22、12.2.2. Referenced Documents2.1 ASTM Standards:4D1356 Terminology Relating to Sampling and Analysis of Atmospheres3. Terminology3.1 For definitions of terms used in this practice, test method, refer to Terminology D1356.3.2 Definitions:3.2.1 limit of detection, LODA value for which exceedence by mea
23、sured mass indicates the presence of a substance at givenfalse-positive rate: 3 estimated standard deviation of estimated mass. mass of a blank.3.3 Definitions of Terms Specific to This Standard:3.3.1 organic carbon (OC)Carbon volatilized in helium while heating a quartz-fiber filter sample to 870C.
24、 Includescarbonates, if present, unless quantified separately. Also includes char formed during pyrolysis of some materials.3.3.2 elemental carbon (EC)Excluding char, light-absorbing carbon that is not removed from a filter sample heated to 870Cin an inert atmosphere.3.3.3 total carbon (TC)Sum of or
25、ganic and elemental carbon.3.3.4 thermogramDigitized output signal of thermal-optical instrument. Shows detector and filter transmittance signals atdifferent temperatures in nonoxidizing and oxidizing atmospheres.3.4 Symbols and Abbreviations:3.4.1 DPMdiesel particulate matter3.4.2 LOD (g/cm2)limit
26、of detection: 3 sw3.4.3 sw (g/cm 2)estimate of w3.4.4 w (g/cm2)standard deviation in collected mass loading determination3.4.5 OC, EC, TC (g/cm2 or g)organic, elemental, and total carbon3.4.6 RSDrelative standard deviation3.4.7 V (L)sampled volume3.4.8 Wb (g)field blank filters EC mass reading3.4.9
27、WEC (g)active filters EC mass reading4. Summary of Test Method4.1 The thermal-optical analyzer has been described previously (1-5). Design improvements have been made over time, but theoperation principle remains unchanged. OC-EC quantification is accomplished through temperature and atmosphere cont
28、rol. Inaddition, the analyzer is equipped with an optical feature that corrects for the char formed during the analysis of some materials.Optical correction is made with a pulsed diode laser and photodetector that permit continuous monitoring of the filter transmittance.transmittance/reflectance.4.2
29、 The main instrument components (transmittance instrument) are illustrated in Fig. 1. The instrument output, called athermogram, is shown in Fig. 2. For analysis, a known area (normally 1.5 cm2) of the quartz-fiber filter sample is removed witha sharp metal punch. Quartz-fiber filters are required b
30、ecause temperatures in excess of 850C are employed. The portion isinserted into the sample oven, and the oven is tightly sealed. The analysis proceeds in inert and oxidizing atmospheres. First, OC(and carbonate, if present) is removed in helium as the temperature is stepped to a preset maximum (abou
31、t 870C(usually 850Cin NMAM 5040). 5040; see 4.4). Evolved carbon is catalytically oxidized to CO2 in a bed of granular MnO2. The CO2 is thenreduced to CH4 in a Ni/firebrick methanator, and CH4 is quantified by a FID. Next, the sample oven temperature is lowered, an3 The carbon analyzer used in the d
32、evelopment and performance evaluation of this test method was manufactured by Sunset Laboratory, 2017 19th Avenue, Forest Grove,Oregon 97116, which is the sole source of supply of the instrument known to the committee at this time. If you are aware of alternative suppliers, please provide thisinform
33、ation to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee which you may attend.4 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Stand
34、ardsvolume information, refer to the standards Document Summary page on the ASTM website.D6877 132oxygen-helium mix (2 % oxygen after dilution of the 10 % oxygen in helium supply) is introduced, and the temperature isincreased to 900C (or higher) to remove the residual carbon. (oxidize) the remainin
35、g carbon, some or all of which is EC,depending on whether char is formed during the first part of the analysis (a char correction is made if so). At the end of eachanalysis, calibration is made through automatic injection of a fixed volume of methane.4.3 Some samples contain components (for example,
36、 cigarette and wood smokes) that carbonize (convert to carbon) orto formchar in helium during the first part of the analysis. Like EC initially present in the sample,typical of fine particle pollution, charstrongly absorbs light, particularly in the red/infrared region. The char formed through pyrol
37、ysis (thermal decomposition) of thesecomponents causes the filter transmittancetransmittance/reflectance to decrease. Charring can begin at 300C; the process maycontinue until the maximum temperature is reached. After OC removal, an oxygen-helium mix is introduced to effect combustionFIG. 1 Schemati
38、c of Thermal-Optical Instrument (V = valve) for Determination of Organic and Elemental Carbon in DPM and Other Car-bonaceous Aerosols.NOTE 1PC is pyrolytically generated carbon (char). Final peak is methane calibration peak. Carbon sources: pulverized beet pulp, rock dust(carbonate), and diesel part
39、iculate.NOTE 2In the comparative test reported by Birch (6), 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 thethis range.FIG. 2 Thermogram for Filter Sample Containing OC, Carbonate
40、(CC), and EC.D6877 133of residual carbon, which includes char and any EC originally present. As oxygen enters the oven, light-absorbing carbon isoxidized and a concurrent increase in filter transmittance occurs. The split (vertical line prior to EC peak in Fig. 2) between OCand EC is assigned when t
41、he initial (baseline) value of the filter transmittance is reached. All carbon removed before the OC-ECsplit is considered organic; that removed after the split is considered elemental. If no char is formed, the split is assigned prior toremoval of EC. Ordinarily, the split is assigned in the oxidat
42、ive mode of the analysis.4.4 Occasionally, original the sample EC (as opposed to char) (along with any char formed) is lost withduring the fourthtemperature step in helium. Loss of EC in helium is uncommon,uncommon but sometimes occurs, possibly due to oxidants in thesample. The In cases when loss i
43、s to an extent where the filter transmittance reaches/exceeds its initial (baseline) value during thefirst part of the analysis (in helium), the OC-EC split is automatically assigned earlier (in helium) in these casesearlier, in heliummode (5). A lower preset maximum (for example, 650C) can be used
44、to reduce EC/char loss in helium so that the split occursduring the oxidative mode (5).4.5 OC and EC results are reported in units g per cm2 of filter deposit. The total OC and EC on the filter are calculated bymultiplying the reported values by the deposit area (slightly less than the filter area).
45、 A homogeneous deposit is assumed. The TCin the sample is the sum of OC and EC. If carbonate is present, the carbon in it is quantified as OC unless correction is made.Additional details about carbonates are given in a following section.5. Significance and Use5.1 The test method supports proposed, p
46、reviously proposed occupational exposure standards (7, 8) for DPM.ADPM exposurelimit has since been promulgated for metal.nonmetal mines, but there currently are no limits for general occupational settings (aproposed limit (7) was withdrawn from the ACGIH Notice of Intended Changes (NIC) list in 200
47、3). In the United States alone,over a million workers are occupationally exposed (9). An exposure standard for mines is especially important because minersexposures are often quite high. NIOSH (9), the International Agency for Research on Cancer (10) (IARC), the World HealthOrganization (11) (WHO),
48、the California Environmental Protection Agency (12), the U.S. Environmental Protection Agency (13)(EPA), and the National Toxicology Program (14) have reviewed the animal and human evidence.All have evidence on DPM andall classified diesel exhaust as a probable human carcinogen or similar designatio
49、n. In 2012, the WHO reclassified diesel exhaustas carcinogenic to humans (Group 1) (15). In addition, in a study of miners, the National Cancer Institute (NCI) and NIOSHreported increased risk of death from lung cancer in exposed workers (16 and 17).5.2 The test method provides a measure of occupational exposure to DPM. Previous studies have produced equivocal resultsbecause exposure data are lacking. Given the economic and public health impact of epidemiological studies, accurate riskassessment is critical. An ongoing The N
