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Environmental Health Division
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 = less than or equal to 24 hours Short-term = greater than 24 hours to 30 days Subchronic = greater than 30 days to 8 years Chronic = greater than 8 years to a lifetime Cancer = 0 to 70 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 | HBV20 | Acute | 30 | Hematotoxicity |
Short-term | 10 | Hematotoxicity | |||
Subchronic | 8 | Hematotoxicity | |||
Chronic | 3 | Hematotoxcity | |||
Cancer | 0.8 | Cancer | |||
106-94-5 | 1-Bromopropane | HBV23 | Acute | 100 | Developmental |
Short-term | 30 | Liver effects | |||
Subchronic | 20 | Nervous system | |||
Chronic | 2 | Nervous system | |||
Cancer | 6 | Skin tumors | |||
106-99-0 | 1,3-Butadiene 1,3 Butadiene (PDF) | HBV10 | Cancer | 0.2 | Cancer |
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) | HBV24 | Acute | 50 | Eye irritation |
Short-term | 7 | Respiratory system | |||
Subchronic | 7‡ | Respiratory system | |||
Chronic | 7‡ | Respiratory system | |||
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) | RAA | Cancer | multiple | Cancer |
7631-86-9 | Silica, Crystalline (respirable PM4) | 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 | 2024 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 | ||||
---|---|---|---|---|---|
CAS Number | Chemical | Value Type | Exposure Duration | Value
| Health Endpoint(s) |
Find chemicals beginning with: A - C D - E F - M N - S T - Z | |||||
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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