Health-Based Values and Risk Assessment Advice for Air

On this page:
Health-Based Values (HBV)
Risk Assessment Advice (RAA)

For a complete list of MDH air guidance values, see the Air Values Table.

Health-Based Values

A Health Based Value (HBV) is the concentration of a chemical (or a mixture of chemicals) that is likely to pose little or no risk to human health. MDH develops HBVs for water and for ambient air.  An ambient air HBV is expressed as micrograms per cubic meter of air (µg/m3). HBVs are developed to protect human health for a specified length of exposure (e.g., one hour, one day, one month, a lifetime). HBVs for air are calculated using the methodology set in the Health Risk Values Rules. HBVs meet the same data requirements as Health Risk Values (HRVs).

MDH develops HBVs when Minnesota agencies need guidance for chemicals that do not have HRVs. MDH may also calculate HBVs to update an existing value if there is significant new scientific information for the chemical and/or to apply new risk assessment methods. If there is reason to believe new toxicologically related information will be released in the near future, MDH will wait for those study or assessment results before developing an HBV.

HBVs have not been promulgated using the public process described by the Administrative Procedures Act (Minnesota Statutes Chapter 14). Instead, an HBV is technical guidance made available by MDH. These values may be used by the public, state and local risk managers, and other stakeholders to assist in evaluating potential health risks to humans from exposures to a chemical.

Risk Assessment Advice

Risk Assessment Advice (RAA) is technical guidance concerning exposures and risks to human health. MDH develops RAA for water and for air. Depending on the information available, RAA may be quantitative (e.g., a concentration of a chemical that is likely to pose little or no health risk to humans) or qualitative (e.g., a written description of how toxic a chemical is in comparison to a similar chemical). Generally, RAA contains greater uncertainty than HRLs, HRVs, and HBVs because the available information is more limited.

MDH develops RAA when Minnesota agencies need guidance for chemicals that do not have Health Risk Limits (HRLs) or Health Risk Values (HRVs). MDH may also calculate RAA to update an existing value if there is significant new scientific information the chemical and/or to apply new risk assessment methods. If there is reason to believe new toxicologically related information will be released in the near future, MDH will wait for those study or assessment results before developing a RAA.

RAA has not been promulgated using the public process described by the Administrative Procedures Act (Minnesota Statutes Chapter 14). Instead, RAA is technical guidance made available by MDH. These values may be used by the public, state and local risk managers, and other stakeholders to assist in evaluating potential health risks to humans from exposures to a chemical. RAA is not likely to change unless significant new data become available.

MDH also develops RAA on a case-by-case basis for specific conditions or specific sites. It is not appropriate to apply this site-specific RAA to other sites without consulting with MDH.

For a complete list of MDH guidance for air, see the Air Values Table.

 

Updated Thursday, November 14, 2013 at 07:52AM