Air Emissions Risk Analysis (AERA) guide

The Air Emissions Risk Analysis guide describes both how an AERA is conducted, and the process involved in reviewing and using the AERA results. This Web page does not contain the most up-to-date information.  The AERA Guidance Updates Web page should be consulted periodically.

The Air Emissions Risk Analysis guide describes both how an AERA is conducted and the process involved in reviewing and using the AERA results.

• Air Emissions Risk Analysis Guidance (aq9-18)

Section 1 (Overview)

• When an AERA should be conducted.
• What a project proposer should expect when contacting and involving the MPCA.
• How the MPCA will conduct reviews.

Section 2 (Quantitative Analysis)

• How to generate a list of chemicals emitted from a facility.
• How to estimate emissions for chemicals having an inhalation health benchmark value (IHB) in the risk analysis screening spreadsheet (RASS).
• How to select dispersion factors for estimating air concentrations.
• How to apply IHBs and multimedia factors to chemical concentrations to estimate multimedia risks (cancer risks and noncancer hazard indices from inhalation and ingestion routes of exposure).

Section 3 (Qualitative Analysis)

• Considers those factors that do not easily lend themselves to numerical risk estimates, or where generating a risk estimate could be done but with greater time and expense to a project proposer and the MPCA.
• In some cases, issues identified in the qualitative section may be further assessed in a focused risk analysis.

Section 4 (Interpreting and Using Results)

• Describes how the AERA results will be used and interpreted.
• The MPCA staff generate a summary memorandum of the AERA — the quantitative results and key qualitative considerations — that is used by the MPCA managers in evaluating options for further action.
• The recommended option resulting from the AERA process is incorporated into the environmental review or air emissions permit process and is available for public comment.

For more information

• Mary Dymond, 651-757-2327
• Kristie Ellickson, 651-757-2336