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Contact Info
Health Risk Assessment Unit
651-201-4899
health.risk@state.mn.us

Contact Info

Health Risk Assessment Unit
651-201-4899
health.risk@state.mn.us

Air Guidance Values

The Minnesota Department of Health (MDH) develops health-based guidance values to evaluate potential human health risks from exposures to chemicals in ambient air.

An air guidance value is a concentration of a chemical that is likely to pose little or no risk to human health. All air values are expressed as micrograms of chemical per cubic meter of air (μg/m3). Air values are developed to protect human health for a specific length of exposure; generally acute (24 hours or less), short-term (>24 hours - 30 days), sub-chronic (>30 days - ~ 8 years), and chronic (>8 years - lifetime) durations.

Air guidance values may be used by the public, industry, state and local risk managers, and other stakeholders to assist in evaluating potential health risks to people from exposures to a chemical in air. These values can be used for assessing risks in the environmental review process, developing air pollution permits, health risk assessments and other site-specific assessments. MDH does not enforce air guidance values.

Air guidance values are developed using public health protective practices that protect susceptible portions of the population (including but not limited to children, pregnant women and their fetuses, individuals compromised by pre-existing diseases, and elderly persons). However, these values may not be protective of hypersensitive individuals who may respond to low level chemical exposures. Additionally, the values do not determine health risk from exposure to several toxic chemicals at once.

There are three categories of air guidance values: Health Based Values (HBVs), Risk Assessment Advice (RAA), and Health Risk Values (HRVs). These values are divided into two tables below: Health-Based Values and Risk Assessment Advice (more current air guidance values) and 2002 Health Risk Values (that were developed over 18 years ago and appear in rule). MDH should be consulted before using the 2002 Health Risk Values.

Health Based Values and Risk Assessment Advice

MDH currently develops Health Based Values (HBVs) and Risk Assessment Advice (RAA) when there is a need for guidance to evaluate health risks to chemicals in air, often by request of the Minnesota Pollution Control Agency or other state agencies. HBVs are developed after undergoing a comprehensive chemical review of available toxicity studies. RAA may contain greater uncertainty than HBVs as a result of a less rigorous chemical review or because toxicity information is more limited. MDH also develops RAA on a case-by-case basis for specific conditions or specific sites. It is not appropriate to apply a site-specific RAA to other sites without consulting MDH.

HBVs and RAA have not been promulgated using a public rulemaking process. Instead, an HBV/RAA is technical guidance made available by MDH.

In 2020, MDH standardized and updated its definitions of durations for air guidance.  The updated duration key is found in the below table, and a more detailed description of the durations can be found in the document Air Exposure Durations (PDF).

Note that because the standardization of duration definitions occurred in 2020, all chemicals reviewed before 2020 may not have the exact same definition for durations.  Please contact MDH if you have questions about a specific duration for a specific chemical. MDH will be updating the list of HBVs and RAAs to make them consistent with the 2020 definitions as time allows.  The date that a chemical review is completed is noted as a subscript under the Value Type in the table.  For example, Acrolein is HBV12, meaning that it is a Health Based Value completed in 2012.

HBVs and RAA have not been promulgated using a public process. Instead, an HBV/RAA is technical guidance made available by MDH.

Duration Key:

Acute = 24 hours or less
Short-term = 24 hours - 30 days
Subchronic = 30 days - 8 years
Chronic = 8 years - lifetime

CAS Number Chemical Name Value Type Exposure
Duration
Value
(µg/m3)
Health Endpoint(s)
107-02-8 Acrolein
Acrolein (PDF)
HBV12 Acute 5 Irritant-eye
Subchronic 1 Upper respiratory system
Chronic 0.4 Upper respiratory system
71-43-2 Benzene

Air Toxicological Summary for Benzene (PDF)

Information Sheet: Benzene in Air (PDF)

HBV20 Acute 30 Hematotoxicity
Short-term 10 Hematotoxicity
Subchronic 8 Hematotoxicity
Chronic 3 Hematotoxcity
Cancer 0.8 Cancer
106-94-5 1-Bromopropane
1-Bromopropane (PDF)
HBV11 Acute 50,000 Development
Subchronic 4,000 Nervous system
Chronic 20 Respiratory system
106-99-0 1,3-Butadiene
1,3 Butadiene (PDF)
HBV10 Cancer 0.2 Cancer
75-71-8
Dichlorodifluoromethane
Guidance for Air - DCDFM (PDF)
RAA16
Subchronic 10,000 None
156-60-5
trans-1,2-Dichloroethylene
Air Toxicological Summary for trans-1,2-Dichloroethylene (PDF)

Information sheet: trans-1,2-Dichloroethylene in Air (PDF)
RAA20 Acute ND --
Short-term ND --
Subchronic 200 Immune effects
Chronic 20 Immune effects
Cancer NA --
NA
Dioxins
Guidance for Air - Dioxins (PDF)
RAA04 Chronic ND* Cancer
50-00-0
Formaldehyde
Air Toxicological Summary for Formaldehyde (PDF)

Information sheet: Formaldehyde in Air (PDF)
HBV19 Acute 50 Eye irritation
Subchronic 9 Eye/nose irritation
Chronic 9 Eye/nose irritation
Cancer ND --
91-20-3
Naphthalene
Guidance for Air - Naphthalene (PDF)

Naphthalene Inhalation Unit Risk Consultation (PDF)
HBV17 Acute 200 Respiratory system
Chronic 9 Respiratory system
Cancer NA --
10102-44-0
Nitrogen Dioxide
Guidance for Air - Nitrogen Dioxide (PDF)
HBV04 Acute 470 Respiratory system
375-73-5

Perfluorobutane sulfonic acid (PFBS)

Air Toxicological Summary for Perfluorobutane sulfonic acid (PFBS) (PDF)

For more information see Per- and Polyfluoroalkyl Substances (PFAS)

RAA22 Acute ND --
Short-term 0.3 Thyroid (E)
Subchronic 0.3‡ Thyroid (E)
Chronic 0.3‡ Thyroid (E)
Cancer NA --
375-22-4

Perfluorobutanoic acid (PFBA)

Air Toxicological Summary for Perfluorobutanoic acid (PFBA) (PDF)

For more information see Per- and Polyfluoroalkyl Substances (PFAS)

RAA21 Acute ND --
Short-term 10 Hepatic (liver) system, Thyroid
Subchronic 10 Developmental, Hematological (blood) system, Hepatic (liver) system, Thyroid
Chronic 10 Developmental, Hematological (blood) system, Hepatic (liver) system, Thyroid
Cancer NA --
355-46-4

Perfluorohexanesulfonic acid (PFHxS)

Air Toxicological Summary for Perfluorohexanesulfonic acid (PFHxS) (PDF)

For more information see Per- and Polyfluoroalkyl Substances (PFAS)

RAA21 Acute ND --
Short-term 0.034 Hepatic (liver) system, Thyroid
Subchronic 0.034 Hepatic (liver) system, Thyroid
Chronic 0.034 Hepatic (liver) system, Thyroid
Cancer NA --
307-24-4

Perfluorohexanoic acid (PFHxA)

Air Toxicological Summary for Perfluorohexanoic acid (PDF)

For more information see Per- and Polyfluoroalkyl Substances (PFAS)

RAA22 Acute ND --
Short-term 1 Developmental, Thyroid
Subchronic 0.5 Hepatic (liver) system, Respiratory system
Chronic 0.5 Hepatic (liver) system, Respiratory system
Cancer NA --
335-67-1

Perfluorooctanoic acid (PFOA)

Air Toxicological Summary for Perfluorooctanoic acid (PFOA) (PDF)

For more information see Per- and Polyfluoroalkyl Substances (PFAS)

RAA21 Acute ND --
Short-term 0.063 Developmental, Hepatic (liver) system, Immune system, Pancreas, Renal (kidney) system, and Thyroid
Subchronic 0.063 Developmental, Hepatic (liver) system, Immune system, Pancreas, Renal (kidney) system and Thyroid
Chronic 0.063 Developmental, Hepatic (liver) system, Immune system, Pancreas, Renal (kidney) system, and Thyroid
Cancer NA --
1763-23-1

Perfluorooctane sulfonic acid (PFOS)

Air Toxicological Summary for Perfluorooctane sulfonic acid (PFOS) (PDF)

For more information see Per- and Polyfluoroalkyl Substances (PFAS)

RAA21 Acute ND --
Short-term 0.011 Adrenal, Developmental, Hepatic (liver) system, Immune, Thyroid
Subchronic 0.011 Adrenal, Developmental, Hepatic (liver) system, Immune, Thyroid
Chronic 0.011 Adrenal, Developmental, Hepatic (liver) system, Immune, Thyroid
Cancer NA --
NA

Polycyclic Aromatic Hydrocarbons (PAHs)

Guidance for Evaluating the Cancer Potency -of Polycyclic Aromatic Hydrocarbon (PAH) Mixtures in Environmental Samples (PDF)

RAA Cancer multiple Cancer
7631-86-9

Silica, Crystalline (respirable PM4)

Silica, Crystalline (respirable PM4) (PDF)

HBV13 Chronic 3 Respiratory
127-18-4 Tetrachloroethylene
Tetrachloroethylene (PDF)
RAA14 Chronic 15 Nervous system
Cancer 2 Cancer
79-01-6

Trichloroethylene

Toxicological Summary: Guidance for Air - Trichloroethylene (PDF)

Information Sheet: Guidance for Trichloroethylene (TCE) in Air (PDF)

HBV18 Acute ND --
Short-term 2 Developmental
Subchronic 2‡ Developmental
Chronic 2 Immune effects
Cancer 2 Cancer
Various

Volatile Organic Compounds

2021 Volatile Organic Compounds Inhalation Toxicity Value Review (PDF)

NA = Not Applicable
ND = Not Derived.

*The Minnesota Pollution Control Agency has calculated an inhalation unit risk of 400 (μg/m3)-1 using the MDH recommended oral slope factor for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD).

† This value may not provide protection for individuals who have been previously sensitized to this chemical.

‡Set at short-term value


2002 Health Risk Values

Health Risk Values (HRV) were adopted into Rule in 2002 using the best peer-reviewed science and public health policies available at the time of their development. For more information, see Health Risk Values Rules for Ambient Air. The application of HRVs is not specified in Minnesota rule. Some HRVs have been superseded by more recent MDH advice, as indicated on the HRV table below. There may be critical new scientific chemical information available since the HRVs were developed. Please contact MDH for further guidance regarding the use of HRVs.

Duration Key:

Acute = one hour averaged exposure concentration
Subchronic = 13-week averaged exposure concentration
Chronic = annual averaged exposure concentration


Find chemicals beginning with: A - C     D - E     F - M    N - S    T - Z   

CAS Number Chemical Value Type Exposure
Duration
Value
(µg/m3)

Health Endpoint(s)
75-07-0 Acetaldehyde HRV02 Cancer 5 Cancer
75-05-8 Acetonitrile HRV02 Chronic 60 Mortality
79-10-7 Acrolein
Updated values available
HRV02 Subchronic 0.2 Upper respiratory system
79-10-7 Acrylic acid HRV02 Subchronic 3 Upper respiratory system
107-13-1 Acrylonitrile HRV02 Cancer 0.1 Cancer
107-05-1 Allyl chloride HRV02 Subchronic 10 Nervous system
7664-41-7 Ammonia HRV02 Acute 3,200 Irritant-eye and respiratory system
Chronic 80 Upper and lower respiratory system
1309-64-4 Antimony Trioxide HRV02 Chronic 0.2 Lower respiratory system
7440-38-2 Arsenic HRV02 Cancer 0.002 Cancer
7784-42-1 Arsine HRV02 Acute§ 200 Hematologic system
Subchronic 0.1 Hematologic system
71-43-2 Benzene
Updated value available: Benzene
HRV02 Acute 1,000 Reproductive/
Developmental
Cancer 1.3-4.5 Cancer
92-87-5 Benzidine HRV02 Cancer 0.0002 Cancer
7440-41-7 Beryllium HRV02 Cancer 0.004 Cancer
542-88-1 Bis (chloromethyl) ether HRV02 Cancer 0.0002 Cancer
74-83-9 Bromomethane (Methyl bromide) HRV02 Acute§ 2,000 Nervous system
Chronic 5 Upper respiratory system
7440-43-9 Cadmium HRV02 Cancer 0.006 Cancer
75-15-0

Carbon Disulfide
Updated Chronic RfC available: Volatile Organic Compounds

HRV02 Acute 6,000 Reproductive/
Developmental
Chronic 700 Nervous system
12789-03-6 Chlordane HRV02 Subchronic 7 Hepatic system
7782-50-5 Chlorine HRV02 Acute 290 Irritant-respiratory system
10049-04-4 Chlorine Dioxide HRV02 Subchronic 0.6 Lower respiratory system
532-27-4 2-Chloroacetophenone HRV02 Chronic 0.03 Upper and lower respiratory system
67-66-3 Chloroform
Chronic RfC available: Volatile Organic Compounds
HRV02 Acute 150 Reproductive/
Developmental
18540-29-9 Chromic Acid Mists and Dissolved Cr (VI) aerosols HRV02 Subchronic 0.02 Upper and lower respiratory system
Cr (VI) Particulates Subchronic 1 Lower respiratory system
Chromium VI Cancer 0.0008 Cancer
8007-45-2 Coke Oven Emissions HRV02 Cancer 0.02 Cancer
98-82-8 Cumene HRV02 Subchronic 4,000 Renal system; endocrine system
96-12-8 1,2-Dibromo-3-Chloropropane HRV02 Subchronic 2 Male reproductive system
106-93-4 1,2-Dibromoethane
Updated Chronic RfC and IUR available: Volatile Organic Compounds
HRV02 Cancer 0.05 Cancer
106-46-7 1,4-Dichlorobenzene
Chronic RfC available:
Volatile Organic Compounds
HRV02 Subchronic 800 Hepatic system
75-09-2 Dichloromethane (Methylene Chloride)
Chronic RfC and updated IUR available: Volatile Organic Compounds
HRV02 Acute 10,000 Nervous system
Cancer 20 Cancer
78-87-5 1,2-Dichloropropane
Chronic RfC and IUR available: Volatile Organic Compounds
HRV02 Subchronic 10 Upper respiratory system
542-75-6 1,3-Dichloropropene
IUR available: Volatile Organic Compounds
HRV02 Chronic 20 Upper respiratory system
62-73-7 Dichlorvos HRV02 Chronic 0.5 Nervous system
77-73-6 Dicyclopentadiene HRV02 Subchronic 3 Renal system
NA Diesel Particulates HRV02 Chronic 5 Lower respiratory system
123-91-1 1,4-Dioxane HRV02 Acute 3,000 Irritant-eye and nasal
108-01-0 2-Dimethylamino ethanol HRV02 Subchronic 70 Upper respiratory system
68-12-2 N,N-Dimethylformamide HRV02 Chronic 30 Hepatic system
106-89-8 Epichlorohydrin HRV02 Cancer 8 Cancer
106-88-7 1,2-Epoxybutane HRV02 Chronic 20 Upper respiratory system
100-41-4 Ethylbenzene
Chronic RfC and IUR available: Volatile
Organic Compounds
HRV02 Acute 10,000 Reproductive/
Developmental
75-00-3 Ethyl Chloride (Chloroethane)
Subchronic RfC available: Volatile Organic Compounds
HRV02 Acute 100,000 Reproductive/
Developmental
111-76-2 Ethylene Glycol Monobutyl Ether (EGBE) HRV02 Chronic 13,000 Hematologic system
110-80-5 Ethylene Glycol Monoethyl Ether HRV02 Acute 400 Reproductive/
Developmental
111-15-9 Ethylene Glycol Monoethyl Ether Acetate HRV02 Acute 100 Reproductive/
Developmental
109-86-4 Ethylene Glycol Monomethyl Ether HRV02 Acute 90 Reproductive/
Developmental
110-80-5 (or 109-86-4) Ethylene Glycol Monomethyl Ether (EGME) or 2-Methoxyethanol HRV02 Subchronic 60 Male reproductive system; hematologic system
50-00-0 Formaldehyde
Updated value available:
Formaldehyde
HRV02 Acute 94 Irritant-eye and respiratory system
Cancer¶ 0.08 Cancer
822-06-0 1,6-Hexamethylene Diisocyanate HRV02 Chronic¶ 0.01 Upper and lower respiratory system
110-54-3 n-Hexane
Updated Chronic RfC available: Volatile Organic Compounds
HRV02 Chronic 2000 Nervous system; upper respiratory system
302-01-2 Hydrazine and Hydrazine Sulfate HRV02 Cancer 0.002 Cancer
7647-01-0 Hydrogen Chloride HRV02 Acute 2,700 Irritant-eye and respiratory system
Chronic 20 Upper respiratory system
74-90-8 Hydrogen Cyanide HRV02 Acute§ 700 Nervous system
Chronic 3 Nervous system; endocrine system
7664-39-3 Hydrogen Fluoride HRV02 Acute 240 Irritant-respiratory system
7783-06-4 Hydrogen Sulfide HRV02 Subchronic 10 Upper respiratory system
7439-96-5 Manganese HRV02 Chronic 0.2 Nervous system
67-56-1 Methanol HRV02 Acute 25,000 Nervous system
78-93-3 Methyl Ethyl Ketone
Chronic RfC available: Volatile Organic Compounds
HRV02 Acute 10,000 Irritant-eye and respiratory system
80-62-6 Methyl Methacrylate HRV02 Chronic¶ 700 Upper and lower respiratory system
101-68-8; 9016-87-9 Methylene Diphenyl Diisocyanate and Polymeric MDI HRV02 Chronic¶ 0.6 Upper and lower respiratory system
NA Nickel and Nickel Compounds HRV02 Acute 11 Irritant-respiratory system
NA Nickel Refinery Dust HRV02 Cancer 0.04 Cancer
12035-72-2 Nickel Subsulfide HRV02 Cancer 0.02 Cancer
7697-37-2 Nitric Acid HRV02 Acute 130 Irritant-respiratory system
79-46-9 2-Nitropropane HRV02 Chronic 20 Hepatic system
108-95-2 Phenol HRV02 Acute 5,800 Irritant-eye and respiratory system
75-44-5 Phosgene HRV02 Acute 4 Irritant-respiratory system
7803-51-2 Phosphine HRV02 Subchronic 3 Decreased body weight
107-98-2 Propylene Glycol Monomethyl Ether HRV02 Subchronic 20,000 Nervous system
75-56-9 Propylene Oxide HRV02 Cancer 3 Cancer
1310-73-2 Sodium Hydroxide HRV02 Acute 8 Irritant-eye, skin, and respiratory system
100-42-5 Styrene
Updated Chronic RfC available: Volatile Organic Compounds
HRV02 Acute 21,000 Irritant-eye and respiratory system
Chronic 1000 Nervous system
127-18-4 Tetrachloroethylene
Updated values available
HRV02 Acute 20,000 Irritant-eye and respiratory system; nervous system
108-88-3 Toluene
Updated Chronic RfC available: Volatile Organic Compounds
HRV02 Acute 37,000 Irritant-eye and respiratory system; nervous system
Chronic 400 Nervous system; upper respiratory system
26471-62-5 2,4-/2,6-Toluene Diisocyanate HRV02 Chronic¶ 0.08 Lower respiratory system
71-55-6 1,1,1-Trichloroethane
Chronic RfC available: Volatile Organic Compounds
HRV02 Acute 140,000 Nervous system
79-01-6 Trichloroethylene
Updated values available
HRV02 Acute 2,000 Reproductive/
Developmental
121-44-8 Triethylamine HRV Acute 2,800 Irritant-eye; transient corneal edema
Subchronic 70 Upper respiratory system
1314-62-1 Vanadium Pentoxide HRV02 Acute 30 Irritant-respiratory system
108-05-4 Vinyl Acetate
HRV02 Chronic 200 Upper respiratory system
75-01-4 Vinyl Chloride
Chronic RfC available:
Volatile Organic Compounds
HRV02 Cancer 1 Cancer
1330-20-7 Xylenes HRV02 Acute 43,000 Irritant-eye and respiratory system; nervous system

§This HRV is for a chemical where there is little magnitude difference between the level where mild irritancy occurs and levels where more severe adverse health effects occur.

¶This HRV may not provide protection for individuals who have been previously sensitized to this chemical.

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Last Updated: 10/03/2022

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