Document n9Qvok0G4Ev72reL10L45qro2

(5) .Mason, "W. P-: Water-Supply, 4th Edition, rewritten, 1913 reprint, cor. .reded. New York, John TITlcy and Sou, Inc. (See p. 390.) (6) Baines, IL: On the Uee of Galvanised Iron for Artesian Wells and for the . Conveyance of Drinking Water. Jour. Franklin Institute, 1890, v I7}.-Bertow, E-, and Weigie, O. Zinc in Water Supplies. Ind. A Eng;' v:#^; Chein., 1932, xriv,-t63. L-, - - _ (S) Anderson, E. A, Reinhnrd, C. E, end Hasunel, W. D.: The Corrosion of "r^'rL One in Chlorinated Drinking Water, Distilled Water, and Chlorinated t--Y. Distilled Water. (In preparation.) ` ? '(9) /lotbian, N. V.; and Ward, A. K.: The Action of Chlorinated Water on Galvanixcd-Iron Tanks. Jour. Royal Army Med. Corps, 1922, xrrix, 163. (10)^ Drinker, K. B_, Fehnel, J. Wn and`Marsh, M.: The Normal Excretion of Zinc in the Urine and Feees of Man. Jour._ BioL Cbem-, 1927, lxzii, 375. * (HJ'Lutz, R. .: The Normal Occurrence of Zinc in Biologic Materials: A Be> >~^'- '--riew of the Literature, and a Study of the Normal Distribution of Zino ^f'Sr'rrin the Bat, Cat, and "Man. Jour.Ind.Hyif., 1926, vili, 177. '-i "inj-rDrinker, F., Thomson, B. M., and Finn, J. li: Metal Fume Fever.' TV. Threshold Doses of Zinc (bade, Preventive Measures, and the Chronic Effects of Repeated Exposure!. Ibi<L,1927, ix, 331. . ~ * . (13).Stargia, C. C., Drinker, P., and Thomson, R- M.: Motel Fume Fever; 1. 'Clinical Observations on the Effect of the Experimental Inhalation of ` Zinc Oxide by Two Apparently Normal Persona Triem., 88. ~ Jffi)'Drinker, P, Thomson, B. M., and Finn, J. X-a Metal Fume Feveri ` IL ^ Besistanoe Acquired by Inhalation of Zinc Oxide on Two Successive Days. ri^unn8. *:w: . " (IS) Drinker, P., Thomson, B. M-, and FSnn,.J. L.: Metal Fume Feven JZL :' ( . :Tha Effects of Inhaling Magnesium Oxide Fume. Idem, 187. - . ' Turner, J. A, and Thompson, Ik IL; Health Hazards of Brass Foundries; L Field Investigations of the Health Hazards of the Bnee-Foundry - Industry, IL Laboratory Studies Briefing to the Pathology of Brass >?j. Foundry-men's Ague. Pub. Health BuB. No. 157, U.S. Public Health ^'..Serviea (Aug, 1925),. . , i `"` ~ 1 *__ I III flj`|1 v~'' * v *r+ JLgty-jiwittji "El^THESIZE frequencyof industrial dusts T--U" M * * ` I -mr . *. ByJL-J. Bnoovnxxs, Smnitarf Enginur, Undad SiaUt PMU StcMK Siniiet, ^ 4 -- 1 w-e* b- vvA'. - y * -a . s i ; * ,??Ihe;question as to the relative significance of various sizes of dust V ' -^ ^__ _=_r_ particles in the production of lung-fibrosis has as yet not been satis-_v_`^^;:` :... fcctorQyanswered by pathologists engaged an this problem. How- ' evo^we'do' knowthat the inhalation of certain industrial dusts has- 'Seen*found to"be associated trith definite injury`to this _ .. _ _____ .'twsdia.'JEence a'knowledge of'thLe xize'frequency of. these^duste-^^^ Tjmghtcaat some li^it on this problem. ' Of equal importance' is the: ` ;1 ' fart that such data wSH determine toa.large degree the type of dust-?^?^.'. s^S EteSs MVlLrt-bisrAaf'p' ass 'SZ 'SSsa sSf ffgNafc ?? &k 7^5 ,; r;fei : Mtt:*.. .J'tiKSf `. Aautii*im 962 Jr - ,'~ and 3 microns in size. 1>Uy l3.pereant.of the ] . - * 'i * ^Vs** ,-be less than 0*6 -micron. These results hare been recently by Scheid (4)'of Germany. Drinker (5), in comparing the size ':, .ff-JT fijv.-? ' * i "!*: . `i*w . "frequency of the particles measured by Moir 'with the particles found by him in the sputum of . men employed in ore mills, found a dose . * - correspondence. - The results of these findings raise two pertinent questions;'namely, (1) to what extent are minute particles f dust r: 1 retained by the human lungs, and (2) do appreciable percentages of-^ industrial duste ever fragment into those minute sizes less than 0.5 micron?..'.." - The work of Drinker (6) and his associates and that of Brown (7) -.* :-!:*.*< .;f'i mH* - .. - (8) oh the retention of certain dusts and fumes by man when known J amounts were breathed, seem to indicate that the coarser suspensions '-|T* ,, V*# *w 'k iX'r. KkRr-if;W -- hr* ';;' ,, \r. J*f-?; * } *-**;* * -were retained more effectively than the more finely divided fumes. . Percentage retention ..was found to be directly proportional to par- -- tieulate size and to the density of dust suspended in the air. Owens(9), upon measuring the amount of dust in expired air of London inhabitants, found that only 25 percent of the dust was retained.1 y The average size of the dust inhaled in Owens' experiments was..;, about 0J5 micron. This work on dust retention seems to bear out - - the theory that dust particles of a size less than 0-5 micron play but f, >5* -l -.v a small role in the problem of industrial dust inhalation and in a manner disposes of the first question raised. The answer to the ,. \n'- second question--that is, the ability of the ordinary industrial process'; to fragment appreciable quantities of dust to a size less than 0.5_y ,, '-r*r;v '-*' ?" micron--is best answered by a particle-size study of the dusts actually . suspended in industrial atmospheres. - The present contribution deals with such a study of the size . frequency of certain industrial dusts encountered in the course of . - rv*''t investigating the health of workers in dusty trades. - In addition, a .* 7 discussion is presented concerning the M-mpling and enumeration of . jf# * "r.- -tv: ' aerial dusts in relation to the results obtained an the size range- of such dusts. r*,-; ... x;. ' , *:. mvsamasm xm kxthods vbkd in bttot v.V " In order to obtain a sample of dust from the air in more or lass unaltemd condition, the Owens jet dust counter (10) was used, since . Jti, i.-h*,-> i***'* #.tf**r^/*k. 't. * ,, Vi i" i i 'v' >": with this instrument the atmospheric dust is directly projected on a.' naked cover slip. Bodhom (11), in his study of the characteristics of this instrument, obtained correlations between the Owens and the impinger apparatus (12), and concluded from his study that the" m. bUv-1 efficiency of the Owens counter is of the same order as the impinger, .. i tB KZT H. a. S7*n*t L alM Otoilaa i fl--lmtnwnMli nhnnir n milnnomiolmwil tTon tin -kni iiih nf nnlT 11 r~nini nf llll^lL . fT-ririir--* **i1hi nn **- r* r*`T` '*--i--1 ---`mi " -- Tuimh if THIS 1f$3cUM^TNWAS NOT A RECORD Of 7~BB~00*19920 1 `A--*--- -1' 1 tfr.. -. me cM^SJ.RiES' ,NC- P1D mr COME FROM-------- ------ -- -_ A 241 T!Sr-`A: * I m "<; 963 or particles between 0.5 micron and 10 microns and that the results' obtained by the Owens counter indicate, for all practical purposes, he dustiness of the air/ Our own experience with this instrument' iso leads us to believe that it samples the dust in the air effectively, ind especially the smaller sized particles. After obtaining dust samples, the cover slips were mounted in the istul manner. The dust particles were" measured by the use of a liar ocular micrometer (13) at a magnification of 1,000 diameters oil immersion objective). The horizontal diameter of at least 200 lost particles in several representative fields was measured for each ample. 'With this magnification it was found possible to measure )articles as small aa 0.5 micron in size, while particles smaller than p are easily dii*fcmgii4ati*d at bia magnification and their * uesence recorded. "r Photographic methods have been suggested end used for meaaur- ag dust particles; but, in order to obtain good photomicrographs, tis fawntin! that the dust particles be in one plane, free from Irownian movement and well dispersed. Since industrial dusts are aldom-of a uniform size, it is difficult to fulfill the first requirement. - it t* beginning of this study a comparison was made between the * esu^ btamed with the direct filar measurement* end the photo* method an a typical industrial dust sample. This compari* on^Rmonstrated that the simpler and less expensive filar method ~ielded practically the Berne results. Since the filar method ful*' ified the requirements of our problem, it was selected for the present 4udy;V *. * 1 ' . r - ' SXSUU1 OF STOUT' Table 1 presents the results of the measurements of some 6,000 ` adustriai dust particles and 18,000 outdoor dust particles. The &tter measurements were obtained during the course of a study { the atmospheric smoke pollution problem in our large cities and re presented for the sake of comparison. The number of samples btamed for each dust, the median size,* and the average frequency, i percent for each size group is indicated in this table. In- all 26 . Muplesof 11 different-kinds of industrial dusts were examined .hese . dusts ranged fturn the dust present in sandblasting opera- , ions to that associated with the fine pulveriring operations in trap Ock and talr. miTlrng lIlUBBTUd r ba ttfaar eaCaad m with at Uw -- sssksSr 24is^r by. PPG. INDUSTRIES,, INC. * , .; ' * L- .?p>-V>.L ' _ - * ,T**untb,,.til 1**.----Siu.-iJrmpitncy dUiributoiountdooofrriavrtiot ut >>-.- - 'V - ' :-. `i'-l-vj'::-.."I' -' ; ' -:i' 'Ir- .:1."V * dad* Oat .' , !*.i.v.*.}Tq>i .*r.v'. .-rlVi . ;!*'V*3 il~. V 1 vAn examination of the data in table 1 discloses a striking difference - X- between the size frequency of outdoor dust and indoor industrial dust. . Ninety-seven percent of the outdoor dust particles were found to be- of a less than i micron in diameter, with a median size of 0.5. micron. Practically no dust particles larger than 1.5 microns were found to exist in outdoor air. These results on the size frequency of. outdoor dust are similar to those obtained by Owens.in London (9). In contrast with this result we find that only 2 percent of the in* dustrial dust particles are less than 0.5 micron, and but 21 percent less than 1 micron. The average (median) size of these particles-was .-found to be 1.5 microns. It is evident from the results shown-in table 1 that the majority (59 percent) of the dust particles presentin. industrial atmospheres investigated by- the writer was found to-be V- - r <: .v between one and three microns jn average diameter, with but 10 per* cent of the particles exceeding 3 microns. ->v One of the interesting findings of the present study is revealed by- ll-yf / .. v.'U *;! .-. . the distribution shown in table 1, which indicates that although no two'industrial dusts have the same-size frequency, differing lor the- same dust created by different operations, yet for all practical purposes-' : . the dust particles fall into very narrow limits, the majority-of thea: . being between 1 and 3 microns. From this evidence on the particle*" ' ;^S*5T5 .%fcj :: - _ size distribution of industrial dusts in sir it is apparent that our coik -.cam should be only for those particles ranging from 0.5 micros'fcT 5 microns, and that the lower limitj>f particle size may certainly.be taken at 0.5 micron. . An application of the size-frequency data presented in table 1 to some of the results obtained in studies of dust concentrations in industry reveals very interesting information. Figure 1 presents a ............ comtpparison between the number of dust particles of different sizes "'lifctiS-DOCUMENT WAS NOT. A RECORD OF 'PPGINDUSTRIES,.INC. DID NOT COME FROM 1 bTo019922_I ir 3 FILES AND CANNOT BE AUTHENTiCATED 2416 aond in the general air of granite cutting plants and that found in ntdoor air in the vicinity of these plants. The average dust counts or both the granite cutting plants (20.2) and the outdoor air (4.7 of particles per cubic foot) are based on about 50 samples btained with the impihger apparatus. It is obvious that if we apply be size-frequency data shown in table 1 (computed with a class nterval of 0.1 micron) to the average dust counts just cited, that in x* V ** ,*. 4 t>-v - :5SiS&P*"VVV- ur --t "3 ' "i , ^U`'' * a_: .- :fc- "5 i, ' t. * -.i * / ** i: ? * ' 1,; ; . : i IT -M' j V--: 4 ^ `* * J * `Wy.fc * .. . ............... he'case of'the indoor samples we cannot expect to obtain appredable mints until the 0.7 micron size and larger sizes ore reached, whereas apparently the opposite.would hold true far the outdoor dust samples, nris result is what one would expect from a consideration of the par* dele-size data of the two types of dusts and is merely presented to hustrate more lucidly the significance of the data. These results *m to indicate very clearly thaLif we are to difiercntiate between r-F- 3 TFffS OOCUMtNT. WAS- NOT A ft&jD * Swf . -v - 3*eiTgab n\ - Brmm^sZs0^AUTtoTfc*TM ' v ' --------------------------------------------------------- `AT-i -dusts present in normal air (not proved to be harmful) andrcertain ' dusts found in industrial air (known to be hazardous), we: should leave-.out of consideration those particles -that ore less than On microa in.diameter. (The two corves actually cross at. 0.6 micron-) r . - ; . jr . -4 . 'rv -.** ?' : Isrtffilft'- * ' Tsm sasiPLcra okd ax.Ax.Tsiaor ixbubthiax. dubt^,J2^. r^From the data presented in this paper'it is apparent that in-order to obtain a representative sample of-industrial dust in air, one-should employ an instrument capable of arresting with a high degreeCof efficiency all kinds of dust, of sizes ranging from 0.5 nucroh'to^mi crons and at both low and high concentrations. In addition^the method of counting the dust in the.samples should have small analyti cal errors and should reveal only those significant particle present in industrial atmospheres. It should not be the aim to count nlTths dust particles which may be present in the samples (as may be accom plished by either the use of high magnifications, dark-field illumina tion, or combinations of 'both), since it is necessary to differentiate between the dust content in normal air and industrial air. As has already been shown in this paper, this difference is sharply marked insofar as the dust particles between 0-5 micron and 5 microns-are concerned; hut this difference would be masked and lost should ** include in our determination the particles of ultnunicroscopic tize which are present in vast numbers in all air. .; S' Many methods have been devised and used for the propose of determining the quantity of dust in. air. Suffice it to say that forjthe purpose of dust nn-mpling in either high or low concentrations^.the . ..__i Greenburg-Smith impinger apparatus (12) now finds universal fiTor. ' V.*. rV-This instrument has been used by the United States Public Health . Service in all of its dust studies for the past 10 years end is also hong ; I v'AtV*^* - - - used by other workers in this country and abroad. Since this.msbu- - 'C ment has already been described in numerous publications, no further . ~ * mention will be mode at this time concerning construction.details or method of operation. However, certain advantages that'lthis instrument-possesses over other dust-sampling instruments should be mentioned. These ere, briefly, a high dust collecting efficiency^** both-low and high concentrations'(98 percent against finely drrided silica dust), simplicity of eonstraction, low cost, and finaflyit'per* t +11*- mits samples to be examined either microscopically, gravimetricaHy, or chemically. Hecentiy, Hatch'(14), in studying the operating characteristics of the modified impinger developed'by hiny investi ^ -igated the effect of particle-eize on the sampling efficiency of ..this i i 1. instrument. Against a silica-dust suspension of approximately ii .*/**;, , microns average diameter, this instrument yielded an efficiency' of more than 98 percent at the normal' sampling.rate of 1 euhic'foot THIS) P0CUMEWT WA%>dHft!ffiiAteRE?Bagj(mst very finely divided magnesium oxide fames, 'P^ JW'Pi^TRlES, INC. DID NOT COME FROM '. ^ .:lT$;KltS:AND CANNOT BE AUTHENTICATED ------------------------- M PPG INDUSTRIES* INC. 1 BB 00 19924 I o ----------------- ***** sI fanned by burning magnesium ribbon in the flame of a blast l&mpj thk instrument showed an efficiency of 55 percent. The method of dust counting employed by us during the past 10 Teao has been presented in detail elsewhere (12) (15). Recently, in order to establish the lower limit of particle size revealed by our standard microscopic technique, quartz dust particles ranging from 0.4 micron to 1.6 microns and averaging 0.9 micron were examined by fas technique. This study showed that with our method of counting dust an experienced observer is capable o' seeing quartz dust particles as grafl as 0.7 micron. Our size-frequency data shows that only 15 percent of "the jiust in industrial air is less than 0.7 micron. It is obvious, therefore, that our present 'method of counting dust is capable of disclosing about 85 percent of the dust particles collected by tmr instrument. The small percentage of dust our method fails to; reveal is negligible, when one takes into consideration the simpEeity of the method, the fact that results may be checked by trained observers, and that it is one of practical application. The best criterion of the value of any method of measurement is its successful use in s practical application. Such a test wss offered in the study of the health of workers exposed to the inhalation of granite eest(16). In this study it was definitely established that s high cor don gristed between the intensity of exposure, to dust and the ee of silicosis and active tuberculosis. It is obvious, therefore, the technique of dust analysis which we have been using consti tutes a valuable index of the hazardousness of dust inhalation. ITlnliBT Tito results of measurements of 18,000 outdoor dust particles showed that nearly all of these are leas than 1 micron in average diameter. The median size was found to be 0.5 micron. In contrast with this asult it was found that only 21 percent of about 6,000 industrial particles were leas than 1 micron in size, the majority (69 percent) - bang between 1 end 3 microns. The median size of the industrial dust particles- was found to be 1.5 microns. These results clearly - adicate* that in conducting industrial dust studies our copoem hwnld .'** only for those particles ranging in size from 0.5 micron to 5 microns. . ie instrumentusedin aemplrng industrial dust in sir, the standard apparatus, is shown to be capable of collecting, with a high ,^=of dfldeucy, dust particles'of the sizes found in this study. - standard method rmut fn dust particles is shown to jfefce nxto account about 85 percent of the dust present in industrial ionospheres. Io addition, our studies have shown that a high coxre- "*t* fcstwwn dust counts obtained with our technique and T*. T?1* silicosis end tuberculosis found in a study of the _ x .2 .V* j-*-sJ*.. . r':--' . THlS; DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DIO.NOT COME FROM yf'$ FILES AND CANNOT BE AUTHENTICATED ----------------. - * / V.t.'VC' of granite catten. . The present study clearly indicates that,'ft* method used in enumerating dust particles collected by theimpiag^r apparatus .constitutes a valuable and practical index of the hazard*' rfwnmoes nt drnrfc inhalation- . ./ H-U- &zrzmczB ,-ysSar *- ` .1 ? p Moir, J.: Report on a Specimen of Dust from SHieotic Lungs. Geaeiil Report of the Miners* Phthisis Prevention Committee, Pretoria,. 1916, ' Appendix 9. . . Watkins-Pitchford, W.: The Situation, Outline, and Dimensions of Mines] Particles Visible by Polarised .Light in Sections of Silicotic Ltmp, . Mounted in Canada Balsam, General Report of the Miners*. Phthisis Prevention Committee, 1916, Appendix 8. Mavrogordnto, A.: The Value of the Kouimeter.. Publications of thS'Sonth African Institute of Medical Research, no. 17. " Scheid. C. F.: The Presentation and Determination of the Dost Deporitcd r in Pneumonocotiotio Tissues. Beite. .Path. Anat u. a. Allg, Paih^,yaL 89, 1932. 4 Drinker, Philip: The SUe-Frequeney and Identification of Certain Phage- eytoead Dusts. Jour. Ind. Hyg, voL 7, no. 7, July 1925. Drinker, P., Thomson, R. M., and Finn, J, L.: Quantitative Measurimrsitj ' of the Inhalation, Retention, and Exhalation of Dusts and Fumss by Man.. L Concentrations of 50 to 450 milligrams per Cubic Meter: Jour, - Ind. Hyg, voL 10, no. 1, Jan. 1928. -H Brown, C. E^ Quantitative Measurements of the Inhalation, Retsattao, and Exhalation of Dusts and Fumes by Man. IL Concentrations Briar 50 milligrams per Cubic Meter. Jour. Ind. Hyg, voL 13, no. 8, Oct. 193L Brown, C. E.: Studies in Dust Retention. HL Factors Involved in the Retention of Inhaled Dusts and Fumes by Man. Jour. Ind. Byg, vaL 13, no. 9, Nov. 193L '-Jw Shaw, N, and Owens, J. S.: .The Smoke Problem of Great Cities. GmsMs . A Co, Ltd., London, England, 1925. Owens, J- S-: Jet Dust Counting Apparatus. Jour. Ind. Hyg, voL A no-lZ April 1923. Badham, Charles, Rcyaer, E.E.G., end Brooee, H. D.: Dust BafgUfaj fa Sydney Sandstone Industries. Report of the Director-General of.PubBo . -Health, New South Walee, December 1927. Greenburg, Leonard, and Bloomfield, J. Jd The Impiager Dust Apparatus aa Used.by the United States Pubiis Health Service. ^Pch. Health Rep, voL 47, no. 12, March 18,1932. Chamot, E. M, and Meson, C. W- Handbook of Chemical' Mlmbseopy. ' - John Wiley end Sons, Inc, Now Tort, 1930, p. 402. : v-`J*-' tTaw-h, Theodore, Warren, Henry,.and Drinker, Philip: Form cf .. the Greenburg-Smlth Impinger far Field Use, With a Study of Its Opi ating Characteristics. Jour. Ind. Byg, voL 14, no. 8, October 1S32-'' Bloomfield, J. Jd Dust in Industry: The Sampling sad Analysis of Indus trial Dusts. Mech. Eng, voL 55, no. 4, April 1933, * " TtT- Russell, JL , Britten, R- H, Thompson, L. R, and Bloomfield, J.-Ji3i , ... ..r, - Health of Workea in Dusty Trades. IL Exposure to Siliceous Dot fJyCUM^WT WAS NOT-A Public Health Bulletin No. 187, July 1929. "rv |N- AUTHENTICATED i Wr vt. ! 7"bToo19^--1 I -------------- 2430 I