Document 3JmJ6M5qegLxgYRaoy81LyrYa
FILE NAME: Celanese (CEL)
DATE: 1957
DOC#: CEL025
DOCUMENT DESCRIPTION: TX Gov Regs on Workplace Exposure Limits -Tab C
NO. 3
OCCUPATIONAL HEALTH REGULATIONS
MAXIMUM PERMISSIBLE CONCENTRATIONS OF ATMOSPHERIC CONTAMINANTS IN PLACES OF EMPLOYMENT
Effective December 1, 1957
(Supersedes American Conference of Governmental Industrial Hygienists Threshold Limit Values for 1956-
April 1957)
CONSULT LOCAL HEALTH DEPARTMENTS AND PHYSICIANS FOR
INFORMATION AND ADVICE ON METHODS OF CONTROL OVER HEALTH HAZARDS TO A LL WORKERS
AND INDUSTRIAL DISEASES AND INJURIES
OH-13-1 5ptmbr 1957
MEDICAL &aiHEALTH UNIT
TEXAS STATE DEPARTMENT OF HEALTH DIVISION OF OCCUPATIONAL HEALTH Austin, Texas
ABC____ Trav____ OODA._
GH " I R D ______ EEWW__ _
Nurse Staff(__
_
Medical Stai"?___ Handle____ scuss_ _
Info______ File_____
Return____ Rote,Return.
THESE STANDARDS WERE ADOPTED BY THE TEXAS STATE BOARD OP HEALTH OH SEPTEMBER 9, 1957 IN ACCORDANCE WITH THE AUTHORITY GRANTED IN
ARTICLE 4418D OF THE REVISED CIVIL STATUTES, STATE OF TEXAS, AND ARE PROMULGATED ALSO IN ACCORDANCE WITH ARTICLE 4477, SECTION 19
SIM0000227
Co m M
CONTENTS I. Scope; Purpose; Availability of Pertinent
References . . . . . . . . . . . . ............... . . . 1 II. Applicability of Figures Listed Herein ............ . . 1 III. Revision . . . . . . . . . ............... . . . . . . . 1 IT. Definitions ............................................ 1 V. Maximum Permissible Concentrations During
One Working Day ............... ............ ............ 2 A. Gases and Vapors . . . . . . B. Toxic Dusts, Fumes and Mists C. Mineral Dusts . . . . . . .
SJM0000228
MAXIMUM PERMISSIBLE CONCENTRATIONS OF ATMOSPHERIC CONTAMINANTS IN PLACES OF EMPLOYMENT
I. Scope; Purpose; Availability of Pertinent References
Scope;
This regulation applies to all places of employment in Texas. It does not cover maximum permissible dose of radiation or the minimum environmental sanitation requirements, nor in clude measures required for control of community external air pollution or air pollution nuisances.
Purpose^
The purpose of this regulation is to preacribe to employers the maximum average atmospheric concentration of contaminants to which they are permitted to expose employees during an eight-hour working day in their places of employment, in cluding industrial establishments.
Perrinenr References: Copies of related laws, regulations, opinions of the Attorney General of Texas, and Advisory Standards currently applicable will be provided to any citizen of Texas upon request.
II. Applicability of Figures Listed Herein
Individual people react differently after excessive exposures to atmospheric concentrations of contaminants in places of employment. Listed herein are weighted average concentrations generally safe in places of employment daring an eight-hour working exposure. These are not maximum values which cannot he exceeded momentarily depending upon, but not limited to, such factors as nature of contaminant; frequency of occurrence of high concentration; variable durations of exposure; probability of acute poisoning from high concentration for even short periods; cumulative effects. Employers shall consider these factors prior to exceeding values listed herein.
III. Revision
Values listed herein are based upon information obtained from recent experience, experimental study reports, or a combination of the two. Regular review will result in revision as Justified. The State Board of Health solicits and will consider pertinent data based upon facts and experiences received from individuals, industries, governmental agencies, or others.
IV. Definitions
1. Industrial Establishment is defined to mean an institution, a place, building or location related to manufactures or to the product of industry or labor.
2. Places of Employment is defined to mean any place where two or more persona are directly or indirectly employed by another for direct or indirect gain or profit. SIM00D229
-2 -
V. MAXIMUM PERMISSIBLE CONCENTRATIONS DURING ONE WORKING PAY
A. Gases and Vapors
.
P.P.M.*
Acetaldehyde ........................................ Acetic acid . ................. . . . . . . . . . . Acetic anhydride . . . ........ . . . . . . . . . . Acetone . ..................... . . . . . . . . . . . (t) Acetylene tetrabrcmide . . . . . . . . ............ Acrolein . . . . . . . . . . ....................... Acrylonitrile . . . . . . . . . . . . .......... , , Allyl alcohol . . . . . . . . . . . . . . .......... Allyl chloride . . . . . ............. . .......... (t) Allyl glycidyl ether (AGE) . . . . . . . . . . . . . Allyl propyl disulfide ................. . . . . . . Ammonia . . . . ........... . . . . . . . . . . . . . Amyl acetate ........... . . . . . . . . . . . . . . Amyl alcohol (isoamyl alcohol) . . . . . . . . . . . Aniline . . . . ........... . . . . . . . . . . . . . Arsine ..................... . . . . . ............ Benzene (benzol) . . . . . . . . . . . . . . . . . . Benzyl c h l o r i d e ........... ................ .. (t) Boron trifluoride . . . . . ......................... Bromine . . .............................. . . . . . . Butadiene (1,3-butadiene) . . . ..................... Butanone (methyl ethyl k e t o n e ) ........ Butyl acetate (n-butyl acetate) ..................... Butyl alcohol (n-butanol) . . . . . ............... . (t) Butyl glycidyl ether (BGE) (n-butyl glycidyl ether) . Butylamine . . . ......... . . . . . . . . . . . . . Butyl cellosolve (2-butoxyethanol) . . . . . . . . . (t) Butyl mercaptan ........... . . . . . . . . . . . . . Carbon dioxide ................. . . . . . . . . . . Carbon disulfide ...................... .. Carbon monoxide ......... . . . . . . . . . . . . . . Carbon tetrachloride ............. . . . . . . . . . Cellosolve (2-ethoxyethanol) . . . . . . . ........ Cellosolve acetate (2-athoxyethyl acetate) . , . . . Chlorine ................... . . . . . . . . . . . . Chlorine trifluoride . ............. . . . . . . . . (t) Chloroacetaldehyde ................. . ............. Chlorobenzene (monochlorobenzene) . . . . . . . . . . (t) Chlorobranomethane (ClBrCH2) ................. .. . . Chloroform (trichloromethane) . . . . . . ........ . 1-Chloro-l-nitrapropane . . . . . . . . . . . . . . . Chloropicrin ........... . . . . . ............. . .
200 10
5 1,000
1
0.5 20
5
5
10 2
100 200 100
5
0.05
25
1 1 1 1,000
250
200 100
50
5
50
10
5,000 20
100
25
200 100
1 0.1 1
75
400
100 20 1
Approx. Mg. per Cu. M.-f-
360
25
20
2,400
14
1.2
45
12
15 45
12
70 1,050
360 19 0.2 80 5 3 7
2,200 740 950 300 270
15 240
35 9,000
60
110
160 740 540
3 0.4 3 350 2,100 490
100
7
Parts of vapor or gas per million parts of air by volume. -^Approximate milligrams per cubic meter of air. (t)Toxicological information or injury reports on these items is of recent
origin and most probably will require revision at an early date.
5IM0Q0Q230
A. GASES AND VAPORS (Cont.)
-3 -
P.F.M.*
Chloroprene (2-chloro-l,3-butadiene) . ............
25
Creaol (all isomers)
5
Cyclohexane . .................
400
- Cyclohexanol . . . . . . . . ....................... 100
Cyclohexanone . . . . . . . . . . . . . . . . . . .
100
Cyclohexene . . . . . . . .......... . . . . . . .
400
Cyclopropane ......... . . . . . . . . . . . . . . .
400
Decaborane ............... .........................
0.05
Diacetane alcohol (4-hydroxy-4-methyl-
2-pentanone) . . . . . ...........................
50
Diborane
........................... . . . . .
0.1
o-Dichlorobenzene . . . . . . . . ........... . . . Dlchlorodifluoromethane . . . .......... . . . . . 1.1- Dichloroethane . . . . . ......................
50 1,000
100
1.2- Dichloroethane (ethylene dichloride) . . . . . . 100
1.2- Dichloroetbylene.......................
200
Dichloroethyl ether ..................... . . . . .
15
Dichloromonofluor one thane . .............
1,000
1,1-Dichloro-l-nitroethane . . . . . . . . . . . . .
10
Dichlorotetrafluoroethane . ............. . . . . . 1,000
Diethylamine . . . . . . .......... . . . . . . . .
25
Difluorodibromcmethane . . . . . . . . . . . . . . .
100
(t) Diglycidyl ether (DGE) .......... . . . . . . . . .
10
Diisobutyl ketone ........ . . . . . . . . . . . .
50
Dimethylaniline ( n - d i m e t hylaniline) ............ .
5
(t) Dimethyl formamide .
20
Dimethylsulfate ...............
1
Dioxane (diethylene dioxide) ........ . . . . . . .
100
(t) Dipropyleneglycolmethylether .................
100
Ethyl acetate ................................... . 400
Ethyl acrylate ............... .................... . '
25
Ethyl alcohol (ethanol) . . . . . . . . . . . . . . 1,000
(t) Ethyl mercaptan ....................... . . . . . .
250
Ethlamine . . . . . . . . . . ................... , 25
E t h y l b e n z e n e ......................................
200
Ethyl bromide ................. . . . . . . . . . .
200
Ethyl chloride . ...............
1,000
Ethyl ether . .................
400
Ethyl f o r m a t e ..................................
100
Ethyl silicate . . . . . . ............... . . . . .
100
Ethylene chlorohydrin .......................
5 *
Approx, hg. per Cu.M.
90 22 1,400 410 400 1,350 690
0.3
240 0.1
300 4,950
400 400 790
90 4.200
60 7,000
75 860
55 290
25 60
5 360 600 1,400 100 1,900 640
45 870 890 2,600
1.200
300 850
16
*parts of vapor or gas per million parts of air by volume. + Approximate milligrams per cubic meter of air. (t) Toxicological information or Injury reports on these items is of recent origin
and most probably will require revision at an early date.
SIM0000231
-4 -
A. GASES AND VAPORS (Cont.)
P.P.M.*
Approx. Mg. Per Cu.M. +.
Ethylenediamine Ethylene dibromide (1,2-dibromoethane) . . . , ,
Ethylene imine .............................. . Ethylene oxide . . . . . . ........ . . . . . . Fliiorine ...................................... F l u o r o t r i c h l o r o m e t h a n e ..................... . Formaldehyde .............. . . . . . . . . . F u r f u r a l .................. ................... (t) Furfuryl alcohol . .................... . . . . Gasoline . , . . ........... .. (t) Glycidol . . . ................ . . . . . . . . Heptane (n-heptane) . . . . . .................. Hexane (n-hexane) . . . ...................... Hexanone (methyl butyl ketone) . . . . . . . . . Hexone (methyl isobutyl ketone) . . . . . . . . . Hydrazine .............. ..................... Hydrogen bromide . . . . . . . . . . . . . . . . Hydrogen chloride . . . . . . . . . . . . . . . . Hydrogen c y a n i d e ........ ................ . . , Hydrogen fluoride ........ . . . . . . . . . . . . Hydrogen peroxide, 90% . . . . . . ............. Hydrogen selenide . . . . ...................... Hydrogen sulfide . . . . . .............. . . . Iodine ........ . . . . . . . . . . . . . . . . Iaophorone ................... ................. (t) isopropyl glycidyl ether (IGE) . . . . . . . . . I s o p r o p y l a m i n e ............ ................... Mesityl oxide . . . . . .................. . . Methyl acetate ................... ........... .. Methyl acetylene ........ . . . . . . ........ Methyl acrylate . . . ............ . . . . . . Methyl alcohol (methanol) . . . . . . . . . . . . Methyl b r o m i d e ........ ..................
Methyl cellosolve (2-methoxyethanol) . . . . . .
Methyl cellosolve acetate (ethylene glycsl monomethyl ether acetate) . . . . . . . . .
Methyl chloride ............... ...............
Methyl a1 (dimethoxyme t h a n e ) .............. .. . . Methyl chloroform (1,1,1-trichloroethane) . . . .
Methyl cyclohexane ........... .. Methyleyelohexanol ........ . . . . . . . . . . Methylcyclohexanone ............ . . . . . . . . *
ID
25
5
50 0.1
1,000 5
5 50
500 50
500
500 100 100
1 5
5 10
3 1 0.05 20 0.1 25
50
5
50 200 1,000
10 200
20 25
25 100 1,000 500
500 100 100
30
190
9
90 0.2
5,600 6
20 200 2,000 150 2,000 1,800 410
410
1.3 17
7 11
2 1.4 0.2 30 1 140
240 12
200 610 1,650
35 260
80 80
120 210 3,100
2,700 2,000
470
460
*Parta of vapor or gaa per million parta of air by volume.
-f> Approximate milligrams per cubic meter of air.
i) Toxicological information or injury reports on these items is of recent origin and most probably will require revision at an early date. SIM0000232
-5 -
A. GASES AMD VAPORS (Cont.)
Methyl ornate . . . . . . . . ............... .
Methyl isobutyl carbinol (methyl amyl alcohol). .
(t) Msthyl mercaptan . ................. ..
(t) Methyl styrene . . . .......... . . . . . . . .
Methylene chloride (dichloromethane) . . . . . .
(t) Monomethyl aniline . ...........................
Naphtha (coal t a r ) ....................... . . .
Naphtha ( p etroleum).......... ............ .. . .
Nickel c a r b o n y l ....................... .. . . . .
Nitric acid ................... ..................
P-Nitroaniline . . . . . . . . . . ........ . .
Nitrobenzene ................... .............. ..
Nitroethane . . ................... . . . . . .
Nitrogen dioxide . . . . . . . . . . . . . . . .
Nitroglycerin . . . . . . . . ...................
Nitromethane . . . . . . . ............... . . .
2-Nitropropane . . . . . . . . . ...............
Nitrotoluene . . . . . . . . . . . . . . . . . .
Octane ...........................
.
Ozone ............................ ..
Pentane . . . . . . . . . . . . . . . . . . . . .
Pentenone (methyl propyl ketone) . . . . . . . .
Perchloroe thylene (tetrachloroethylene)........
(t) Perchloratethyl m e r c a p t a n ................. . . .
Phenol .. ........................................
(t) Phenyl glycidyl ether ( p G E ) .......... ..........
Phenylhydrazine . . . . . . . . . . . . . . . . .
Phosgene (carbonyl chloride) . . . . . . . . . .
Phosphine ........... ................ ............
Phosphorus trichloride . . . . . . . . . . . . .
Propyl scetate . . . . . . . ........ . . . . .
Propyl alcohol (isopropyl alcohol) . ...........
Propyl ether (isopropyl ether) . . . . . . . . . .
Propylene dichloride (1,2-dichloropropane) , . .
Propylene I m i n e ..................................
(t) Propylene oxide ................................ .
P y r i d i n e ........................................
Quinone . . . . . . . . . . . . . . . . . . . .
S tibine .........................................
Stoddard solvent . . . . . . . . . . . .........
Styrene monomer (phenylethylene) . . . . . . . .
Sulfur dioxide . . . . . . . . . . . . . . . . .
P.M.*
Approx. Mg. Per Cu.M. +
100
25
50 100
500 2
200
500 0.001
5 1 1 100
5
0.5 100
50
5
500 0.1
,000 200 200
0.1
5
50
5 1
0.05
0.5 200 400
500
75
25 100
10 0.1 0.1
500 100
5
250 100 100 480
1,750 9
800 2,000
0 .007 25
6 5 310 9
5 250 180
30 2,350
0. 2,950
700 1,350
0. 19 310 22 4 0. 3
840 980 2,100 350
60 240
30
O.i 0 ., 2,900
420 13
Parts of vapor or gas per million parts of air by volume. Approximate milligrams per cubic meter of air.
(t) Toxicological information or Injury reports on these items is of recent origin and most probably will require revision at an early date.
SIM0000233
- 6 -
A. GASES AND VAPORS (Cont.)
Sulfur hexafluoride ......... , Sulfur monochloride . . . . . . Sulfur pentaflupride . . . . < -Tertiary butyl toluene . . . (t) Tertiary butyl alcohol . . , . 1,1,2,2-Tetrachloroethane . . . Tetrahydrofuran . . . . . . . . Tetranitromethane ............. Toluene (toluol) . . . . . . . c.-Toluidine .................... (t) Tolylene-2,4-diisocyanate , , . Trichloroethylene ......... . , (t) Triethyl amine ............... Trifluaromonobromomethane . . . Turpentine . . . . . ......... Vinyl chloride (ch].oroethylene) (t) Vinyl toluene . . . . ......... Xylene (xylol) . . . . . . . . (t) Xylldine . . . . . . . . . . . (#)(t) Teflon decomposition producta . <[#)(*) Pentaborane (B5E9) . . . . . .
P.P.M.*
Approx. M r . Per C u .M. j-
1,000 1
0.025 10
100
5
200 1
200
5 0.1
200
25
1,000 100
500
100 200
5 0 0
6,000 6
0.25 60 300 35 590
S
750 22 0.7
1,050
100 6,100
560 1,300
480
870
25 0 0
B. TOXIC DUSTS. FUMES. AND MISTS
Mg- Pe^ _ Cu. M. T*
Aldrin (1,2,3,4,10,10-hexachloro-l,4,4a,5,8,Ba-
hexahydro-l,4,5,8-dimethanonaphthalene).......................
Ammate (ammonium sulfamate) . . . . . . . . . . . . . . . . . . .
Antimony . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ANTU (alpha naphthyl thiourea) . . . . ............... . . . . .
Arsenic . . . . . . . . . . . . . . . . . ............. . . . .
Barium (soluble compounds) ...................... ................
(t) B e r y l l i u m ...............
Cadmium oxide fume . . . . . . . . . ................. . . . . .
Calcium arsenate ................................................. Chlordane (1,2,4,5,6,7,8,. 8-octachloro-3a,4,7,7a-
. tetrahydro-4,7-methanoindane) .................
Chlorinated eamphene, 607 ........ ................
........ ..............
Chlorinated diphenyl oxide . . . . . . . . . . . .......... . .
0.25 15 0,5 0.3 0.5
0.5 0.002 0.1 0.1
2 0.5 0.5
* Parts of vapor or gas per million parts of air by volume.
Approximate milligrams per cubic meter of air.
(t) Toxicological information or injury reports on these items is of recent origin and most probably will require revision at an early date.
(#) Until more data are forthcoming, it is important that atmospheric concentra tions of these materials to which workers are exposed must be kept as near 0
as possible.
Milligrams of dust, fume, or mist pur cubic mater of air.
SIM0000234
-7 -
B. TOXIC DUSTS. FUMES AND MISTS (Cont.)
Chlorodlphenyl (427. chlorine) ..............................
Chlorodlphenyl (547 chlorine) . . . . . . . . . . . ........
Chromic acid and chromates (aa CrOO . . . . . . . . . . . .
Crag herbicide (sodium 2- /?,4-dichlorophenojc
ethanol hydrogen sulfate) .......... . . . . . . . . . .
Cyanide (as CN) . . . . . . . . . ................ . . . . .
2,4-D(2,4-dichlorophenoxyacatic acid) . . . . . . . . . . . .
DDT (2,2-bis/p-chlorophenyl7 -1,1,1-trichloroethane) . . . .
Dialdrin (1,2,3,4,10,10-hexaehloro-6,7-epoxy1,4,4a, 5,6,7,8,8a-octahydro-l,4,5,8-dimethano-
naphthalene . . . . ........ . . . . . . . . . . . . . . .
Dinitrobenzene .......... . . . . . . . . . . . . . . . . .
Dinitrotoluene .............. ................ ...........
Dinitro-o-cresol . . . . . . . . . . . . . . . . . . . . . .
BFN (O-ethyl 0--nitrophenyl thionobenzenephosphonate) . . .
Ferbsm (ferric dimethyl dithiocarbamate) . . . ............
Ferrovanadium dust . . . . . . . . . ............ . . . . .
Fluoride ........ . . . . . . . . . . .................. .
HETP (hexaethyl tetraphosphate) . . . . . ........ . . . . .
Hydroquinone . . .............. . . . . . . . . . . . . . .
Iron oxide fume . . . . . . . . . . . ......................
Lead .............. ......................................
Lead arsenate .............. . . . . . . . . . . . . . . . .
Lindane (hexachlorocydohexane, gamma Isomer) . . . . . . . .
(t) Lithium hydride ..........................
Magnesium oxide fume . . . . . . . . . . . . . . . . . . . .
Malathlon (0,0-dimethyl dithiophoaphate of
diethyl mercaptosuccinate) ............................ .
Manganese ............ . ........................ . . . . .
Mercury ........................................ .
Mercury (organic compounds) .............. . . . . . . . . .
Methoxychlor (2,2-di-p-methoxyphenyl-1,1,1-
trlchloroethane) . . . . . . . . . ........ . . . . . . .
Molybdenum (soluble compounds) . . . . . . . . . . . . . . .
(insoluble compounds) ...........................
Nicotine . . ......... . . . . . . . . . . . . . . . . . .
(t) Faradichlurobenzene . . . ........ . . . . . ..............
Farathion (0,0-diethyl 0--nitrophenylthiophoaphate) . . . .
Fentachloronaphthalene .............................
Pentachlorophenol . . . . ........ . . . . . ............
Phosphorus (yellow) .............. . . . . . . . . . . . . .
Phosphorus pentachlorlda . . . . . . . . . . . . . . . . . .
Phosphorus pentasulfide . . . . . . .
.....
Picric a c i d .......................................... .
Mg. per Cu'. M.
1 0.5 0.1
15 5 10 1
0.25 1 1.5 0.2 0.5 15 1 2.5 0.1 2 15 0.2 0.15 0.5 0.025 15
15 6 0.1 0.01
15 5 15 0.5 450 0.1 0.5 0.5 0,1 1 1 0.1
\ _________________________ 4* Milligrams of dust, fume, or mist per cubic meter of air.
(t) Toxicological information or Injury reports on these items is of recent origin and most probably will require revision at an early date.
SIM0G0023S
-8 -
B. TOXIC DUSTS. FUI1ES AKD MISTS (Cont.)
Ilg. per Cu. H. 4
Pyre t h r u m ........................,*.................... .. .
Rotenone ......... . . . . . . ...........................
Selenium compounds (as S e ) .......... ....................
Sodium hydroxide ..........................................
Sodium fluoroacetate (1080). . . . . . . . . . .................
S t r y c h n i n e ................. ............................
Sulfuric acid . . . . . . . . .............................
TEDP (Tetraethyl dithionopyrophosphate) ............ . . .
TEPP (Tetraethylp y r o p h o s p h a t e )...........
Tellurium
..................... ..
Tetryl (2,4, G-trinitrophenylmethyinitramine) . . . . . . .
Thiram (tetramethyl thiuram disulfide) ............... . .
Thallium (soluble compounds) .................... . . . . .
Titanium d i o x i d e ....................................... .. .
Trichloronaphthalene . . . . . . . . . . . . . . . . . . .
Trinitrotoluene . . . . . . ................. . ........
Uranium (soluble compounds) . . . . . . . .................
(insoluble compounds) . . . . . . . . ........ . .
Vanadium
(V2O5 d u s t ) ..................... ....................... (V2O 5 fume) . ............. . .......................... Warfarin (3- /a-acetonylhenzyl / -4 -hydroxycoumarin) . . . .
(t) Yttrium andinorganiccompounds . . . . . ...................
Zinc oxide fumes ........... . . . . . . .................
Zirconium compounds (as Zr)
............. ..
2 5, 0.1 2
0,1 0.15 1 0.2 0.05 0.1 1.5 5 0.1 15 5 1.5 0.05 0.25
0.5 0.1 0.5 5 15 5
C. MINERAL DUSTS
M.P.P.C.F.**
Aluminum o x i d e .........................
50
A s b e s t o s ............... ........................ ..
5
- Dust (nuisance, no free silica) . . . . . . . . . . . . . .
50
Mica (below 5% free s i l i c a ) ................... ............
20
Portland cement . ........... . . . . . . . . . . ........
50
T a l c ..........
20
Silica
High (above 50% free S ^ } ..............................
5
Medium (5 to 50% free S i 0 2 ) ........ ....................
20
Low (below 5% freeSi02). . . . . . . . . . . . . . . .
50
Silicon carbide . . . . . . ......................... . .
50
Soapstone (below 5%freeS102)
20
Hr Milligrams of dust, fume, or miBt per cubic meter of air.
(t) Toxicological information or injury reports on these items is of recent origin and most probably will require revision at an early date.
** Millions of particles per cubic foot of air.
SIM0000236
