Rhode Island Code of Regulations › Title 250 - Department of Environmental Management › Chapter 120 - Air Resources › Subchapter 05 - Air Pollution Control › Part 22 - Air Pollution Control Regulation No. 22 - Air Toxics › Section 250-RICR-120-05-22.9 - Table I Acceptable Ambient Levels

Current through June 14, 2024
Table I Acceptable Ambient Levels (AALs)
								  (
µg/m3)
CHEMICAL NAME
CAS #
1-hour
24-hour
Annual
Acetaldehyde
75070
0.5
Acetamide
60355
0.05
Acetonitrile
75058
60
Acetophenone
98862
300
2-Acetylaminofluorene
53963
0.0008
Acrolein
107028
0.2
0.02
Acrylamide
79061
0.0008
Acrylic Acid
79107
6,000
1
Acrylonitrile
107131
200
0.01
Aldrin
309002
7
0. 1
0.00002
Allyl Chloride
107051
1
2-Aminoanthraquinone
117793
0.1
4-Aminobiphenyl
92671
0.0002
Ammonia
7664417
1,000
100
70
Aniline
62533
1
0.6
o-Anisidine
90040
0.02
Antimony & compounds, except
								  trioxidea
0.2
Antimony trioxide
1309644
0.2
0.02
Aramite
140578
0.1
Arsenic &
								  compoundsa (inorganic)
0.2
0.0002
Arsine
7784421
200
0.05
Asbestos
1332214
4b
Azobenzene
103333
0.03
Barium
7440393
700
Benzene
71432
30
20
0.1
Benzidine
92875
0.00002
Benzoic acid
65850
10,000
Benzotrichloride
98077
0.0003
Benzyl chloride
100447
200
0.02
Beryllium &
								  compoundsa
0.02
0.0004
Biphenyl
92524
200
Bis (chloromethyl) ether
542881
1
0.00002
Bis (2-ethylhexyl) phthalate (DEHP)
117817
70
0.4
Boron and borates
10
Bromates (including Potassium bromate)
10
0.007
Bromine &
								  compoundsj
(except Hydrogen bromide & Bromates)
2
Bromodichloromethane
75274
100
70
0.03
Bromoform
75252
2,000
70
0.9
1,3-Butadiene
106990
0.03
Butyl benzyl phthalate
85687
700
Cadmium &
								  compoundsa
0.1
0.0006
Calcium cyanamide
156627
1
Captan
133062
500
1
Carbaryl
63252
300
Carbon disulfide
75150
6,000
700
Carbon tetrachloride
56235
2,000
200
0.07
Carbonyl sulfide
463581
200
30
Catechol
120809
6,000
5
Chloramben
133904
50
Chlordane
57749
0.7
0.001
Chlorinated paraffins
(avg length C12- C13, 60% chlorine)
10817126 2
0.04
Chlorine
7782505
200
6
0.1
Chlorine dioxide
10049044
3
0.2
Chloroacetic acid
79118
30
7
2-Chloroacetophenone
532274
0.03
4-Chloroaniline
106478
10
1
Chlorobenzene
108907
1,000
Chlorobenzilate
510156
70
0.7
1-Chloro-1,1-difluoroethane (CFC 142B)
75683
50,000
Chlorodifluoromethane (HCFC-22)
75456
50,000
Chloroform
67663
100i
0.2
Chloromethyl methyl ether
107302
0.001
2-Chlorophenol
95578
20
4-Chloro-o-phenylenediamine
95830
0.2
Chloropicrin
76062
30
0.4
Chloroprene
126998
1
p-Chloro-o-toluidine
95692
0.01
Chromium III &
								  compoundsa (insoluble salts)
5,000
Chromium VI &
								  compoundsa- mists and aerosols
0.008
0.00008
Chromium VI &
								  compoundsa - solid particulate
1
0.00008
Cobalt &
								  compoundsa
0.001
Coke oven emissions
8007452
0.002
Copper &
								  compoundsa (except Copper cyanide)
100
2
p-Cresidine
120718
0.02
Cresols/Cresylic acid, isomers and mixtures
								  (Methylphenols)
1319773
600
Cumene
98828
400
Cupferron
135206
0.02
Cyanide & compounds
								  (inorganic)j, except Hydrogen cyanide
300
9
Cyclohexane
110827
6,000
2,4-Diaminoanisole
615054
0.2
2,4-Diaminotoluene
95807
0.0009
Diazomethane
334883
0.8
Dibromochloromethane
124481
300
70
1,2-Dibromo-3-chloropropane
96128
0.2
0.0005
Dibutylphthalate
84742
2,000
300
1,2-Dichlorobenzene
95501
2000
300
1,4-Dichlorobenzene (p-Dichlorobenzene)
106467
12,000
800
0.09
3,3'-Dichlorobenzidene
91941
0.003
Dichloro diphenyl dichloroethylene (DDE)
3547044
0.01
cis- 1,2-Dichloroethene
156592
3,000
1,000
trans- 1,2-Dichloroethene
156605
800
70
Dichloroethyl ether (Bis (chloroethyl)
								  ether)
111444
100
0.003
2,4-Dichlorophenoxyacetic acid
94757
30
1,3-Dichloropropene
542756
20
0.2
Dichlorvos
62737
20
3
0.01
Dieldrin
60571
0. 2
0.0002
Diethanolamine
111422
3
Diethyl sulfate
64675
0.003
1,1-Difluoroethane (HCFC 152a)
75376
40,000
3,3'-Dimethoxybenzidine
119904
0.0008
p-Dimethyl aminoazobenzene
60177
0.0008
n,n-Dimethyl aniline
121697
7
3,3'-Dimethyl benzidine
119937
0.0002
Dimethyl carbamoyl chloride
79447
0.0003
Dimethyl formamide
68122
30
1,1-Dimethyl hyrazine
57147
0.5
0.001
1,2-Dimethyl hyrazine
540738
3
0.000006
2,4-Dimethylphenol
105679
70
Dimethyl phthalate
131113
10
Dimethyl sulfate
77781
0.0002
4,6-Dinitro-o-cresol
534521
10
2,4-Dinitrophenol
51285
30
7
2,4-Dinitrotoluene
121142
200
7
0.01
1,4-Dioxane (1,4-Diethyleneoxide)
123911
3,000
0.1
Epichlorohydrin
106898
1,000
0.8
1,2-Epoxybutane
106887
2
Ethyl acrylate
140885
0.5
Ethyl benzene
100414
40,000
3,000
1,000
Ethyl carbamate (Urethane)
51796
0.003
Ethyl chloride (Chloroethane)
75003
40,000
10,000
Ethylene dibromide (Dibromoethane)
106934
9
0.02
Ethylene dichloride (1,2-Dichloroethane)
107062
0.04
Ethylene glycol
107211
2,000
400
Ethylene glycol monobutyl ether
111762
10,000
1,000
Ethylene glycol monoethyl ether
110805
400
200
70
Ethylene glycol monoethyl ether acetate
111159
100
Ethylene glycol monomethyl ether
109864
90
20
Ethylene glycol monomethyl ether acetate
110496
90
Ethylene imine (Aziridine)
151564
0.00005
Ethylene oxide
75218
200
0.01
Ethylene thiourea
96457
0.08
Ethylidene dichloride (1,1-Dichloroethane)
75343
0.6
Fluorides &
								  compoundsj, including Hydrogen fluoride
20
3
Formaldehyde
50000
50
40
0.08
Glutaraldehyde
111308
0.08
Heptachlor
76448
2
0.4
0.00008
Hexachlorobenzene
118741
30
0.4
0.0002
Hexachlorobutadiene
87683
0. 7
Hexachlorocyclohexanes, technical grade &
								  mixed isomers
608731
0.002
alpha-Hexachlorocyclohexane
319846
0.0006
beta-Hexachlorocyclohexane
319857
200
2
0.002
gamma-Hexachlorocyclohexance (Lindane)
58899
10
0.04
0.003
Hexachlorocyclopentadiene
77474
100
0.2
Hexachloroethane
67721
60,000
0.3
Hexamethylene-1,6-diisocyanate
822060
0.2
0.03
Hexamethylphosphoramide
680319
0.00005
Hexane
110543
700
Hydrazine
302012
5
0.0002
Hydrochloric acid (Hydrogen chloride)
7647010
2,000
9
Hydrogen bromide
10035106
20
Hydrogen cyanide
74908
300
3
Hydrogen sulfide
7783064
40
30
10
Hydroquinone
123319
1,000
5
Isophorone
78591
700
Isopropanol
67630
3,000
Lead & compoundsa,
								  inorganic
0.008
Lead - tetraethyl lead
78002
0. 0003
Maleic anhydride
108316
10
0.7
Manganese &
								  compoundsa
0.05
0.04
Mercury & compounds. 
								  a - elemental &
								  inorganic
2
0.3
0.009
Mercury - methylmercury
22967926
0. 3
0. 003
Methanol
67561
30,000
4,000
Methoxychlor
72435
20
Methyl bromide (Bromomethane)
74839
200
5
Methyl chloride (Chloromethane)
74873
1,000
400
90
Methyl chloroform (1,1,1-Trichloroethane)
71556
9,000
6,000
5,000
4,4-Methylene bis (2-chloroaniline)
101144
0.002
Methylene chloride (Dichloromethane)
75092
2,000
1,000
2
4,4-Methylenedianiline
101779
700
300
0.002
Methylene diphenyl diisocyanate
101688
0.6
Methyl ethyl ketone (2-Butanone)
78933
10,000
5,000
Methyl hydrazine
60344
0.0004
Methyl iodide (Iodomethane)
74884
30
Methyl isobutyl ketone (Hexanone)
108101
3,000
Methyl isocyanate
624839
1
Methyl methacrylate
80626
700
Methyl tert butyl ether(MTBE)
1634044
7,000
3,000
Michler's ketone
(4,4'-Bis (dimethylamino) benzophenone)
90948
0.004
Fine mineral fibersc
20
Molybdenum &
								  compoundsa
20
Naphthalene
91203
3
0.03
Nickel and compoundsa,
								  except Nickel subsulfide
6
0.2
0.004
Nickel subsulfide
12035722
6
0.2
0.002
Nitric acid
7697372
90
Nitrobenzene
98953
2
4-Nitrobiphenyl
92933
0.00002
4-Nitrophenol
100027
0.1
2-Nitropropane
79469
20
0.1
N-Nitrosodi-n-butylamine
924163
0.0006
N-Nitrosodiethylamine
55185
0.00002
N-Nitrosodimethylamine
62759
0.00007
N-Nitrosodiphenylamine
86306
0.4
N-Nitrosdi-n-propylamine
621647
300
0.0005
N-Nitroso-n-methylethylamine
10595956
0.0002
N-Nitroso-n-methylurea
684935
0.00003
N-Nitrosomorpholine
59892
0.0005
N-Nitrosopiperidine
100754
0.0004
N-Nitrosopyrrolidine
930552
0.002
Parathion
56382
20
0.1
Pentachloronitrobenzene (Quintozene)
82688
10
Pentachlorophenol
87865
20
4
0.2
Phenol
108952
80
200
p-Phenylenediamine
106503
0.2
Phosgene
75445
4
0.3
Phosphine
7803512
0.3
Phosphoric acid
7664382
7
Phosphorus, white
7723140
20
0. 07
Phthalic anhydride
85449
7,000
20
Polychlorinated biphenyls (PCBs), except Aroclor
								  1254
1336363
0. 2
0.001
PCBs- Aroclor 1254
11097691
0.07
Polychlorinated dibenzo dioxins (PCDDs),
								  Polychlorinated dibenzo furans (PCDFs) and dioxin-like Polychlorinated
								  biphenyls (PCBs)
3 x 10-9
															d
Polycyclic Organic Matter
0.00009e
1,3-Propane sultone
1120714
0.001
beta-Propiolactone
57578
0.0002
Propionaldehyde
123386
8
Propoxur (Baygon)
114261
10
0. 1
n-Propyl bromide (1-Bromopropane)
106945
5,000
1,000
Propylene
115071
3,000
Propylene dichloride (1,2-Dichloropropane)
78875
200
4
0.1
Propylene glycol monomethyl ether (PGME)
107982
7,000
Propylene oxide
75569
3,000
0.3
1,2-Propylenimine (2-Methyl aziridine)
75558
0.0001
Quinoline
91225
0.001
Quinone
106514
1
Selenium &
								  compoundsa, except Hydrogen selenide and Selenium
								  sulfide
20
Selenium - Hydrogen selenide
7783075
5
Selenium sulfide
7446346
20
0.2
Sodium hydroxide
1310732
8
5
Styrene
100425
9,000
1,000
100
Styrene oxide
96093
0.02
Sulfatesf
100
20
Sulfuric acid and
								  Oleumg
100
1
1,1,1,2-Tetrachloroethane
630206
100
1,1,2,2-Tetrachloroethane
79345
2,000
Perchloroethylene)
127184
1,000
0.2
Tetrachlorophenols
25167833
90
1,1,1,2-Tetrafluoroethane
811972
80,000
Thioacetamide
62555
0.0006
Titanium tetrachloride
7550450
10
0.1
Toluene
108883
4,000
300
2,4-Toluene diamine (2,4-Diaminotoluene)
95807
0.0009
2,4-and 2,6-Toluene
								  diisocyanateh
26471625
0.07
o-Toluidine
95534
0.02
Toxaphene (Chlorinated camphene)
8001352
20
4
0.0003
1,2,4-Trichlorobenzene
120821
30
1,1,2-Trichloroethane
79005
10
Trichloroethylene
79016
10,000
500
0.5
Trichlorofluoromethane
75694
1,000
2,4,5-Trichlorophenol
95954
300
2,4,6-Trichlorophenol
88062
0.3
Triethylamine
121448
3,000
7
Trifluralin
1582098
30
3
2,2,4-Trimethylpentane
540841
3,000
Vanadium &
								  compoundsa
0.2
Vinyl acetate
108054
200
20
Vinyl bromide
593602
3
0.005
Vinyl chloride
75014
1,000
100
0.2
Vinylidene chloride (1,1-Dichloroethylene)
75354
200
70
Xylenes, isomers and mixtures
1330207
9,000
3,000
100
Zinc &
								  compoundsa
1,000
30
aFor metal compounds,
								  concentrations apply to the metal portion of the compound.
bAsbestos units are
								  fibers/cubic meter.
cFine mineral fibers
								  are mineral fiber emissions from facilities manufacturing or processing glass,
								  rock, or slag fibers or other mineral derived fibers of average diameter 1
								  micrometer (µm) or less.
dPCDD AAL is in terms
								  of 2,3,7,8-tetrachlorodibenzodioxin equivalents, calculated as specified in the
								  Rhode Island Air Toxics Guideline.
ePolycyclic Organic
								  Matter AAL is in terms of benzo(a)pyrene equivalents, calculated as specified
								  in the Rhode Island Air Toxics Guideline."
fSulfates AALs apply
								  to ammonium bisulfate [(NH4)HSO4,
								  CAS 7803-63-6], ammonium sulfate
								  [(NH4)2SO4,
								  CAS 7783-20-2], ferric sulfate
								  [Fe(SO4)3, CAS 10028-22-5] and
								  sodium sulfate [Na2SO4, CAS
								  7757-82-6]
gSulfuric acid and
								  oleum AALs apply to sulfuric acid
								  (H2SO4, CAS 7664-03-9), sulfur
								  trioxide (SO3, CAS 7446-71-9) and oleum
								  (H2SO4 +
								  SO3, CAS 8014-95-7)
hIncludes 2,4-TDI (CAS
								  584849), 2,6-TDI (CAS 91087) and 2,4/2,6 mixtures (CAS 26471625)
iOne-hour AAL for
								  chloroform should be compared to 7 to 8-hour average concentrations.
jFor bromine, cyanide
								  and fluoride compounds, concentrations apply to the bromine, cyanide or
								  fluoride portion of the compound