Risk Assessment Procedures for Rules 1401, 1401.1, and 212
Risk assessment procedures, including procedures for a simple risk screening, were developed by South Coast Air Quality Management District (South Coast AQMD) staff for the adoption of Rule 1401 - New Source Review for Toxic Air Contaminants, in June 1990. These procedures are for the preparation of health risk assessments (HRAs) under Rule 1401, Rule 1401.1 - Requirements for New and Relocated Facilities Near Schools, and Rule 212 – Standards for Approving Permits and Issuing Public Notice and the document is intended to be a “living” document which staff will update periodically, as necessary. Past procedures will be archived and available for use based on the deemed complete date of permit applications. Please note that these risk assessment procedures should not be used for Rule 1402 – Control of Toxic Air Contaminants from Existing Sources or the Air Toxics “Hot Spots” Program (AB 2588), which has its own procedures.
Current Risk Assessment Procedures and Corresponding Resources:
The web-based HRA Tool with associated Emissions Calculator spreadsheet replaces the various tables found in previous Attachments and the Excel-based Risk Tool. The HRA Tool relies on the equations in the Risk Assessment Procedures to calculate health risks and is required for permit applications deemed complete on and after December 1, 2024.
Risk Assessment Procedures Version 9.0
Procedures, equations, and assumptions effective on or after December 1, 2024
HRA Tool
- HRA Tool - Effective for applications deemed complete on or after December 1, 2024
The HRA Tool automates the Rule 1401(e)(1) Risk Assessment Procedures for conducting Tier 1, 2, or 3 HRAs and eliminates the need to reference printed tables to find the appropriate factors to use. Users will find the same source types and source characteristics they have been used to, with the same limitations. The HRA Tool cannot be used for: 1) sources where the parameters are outside the range of values allowed in the drop-down list; 2) non-combustion point sources with a stack shorter than 14-feet; or 3) non-combustion volume sources with a building taller than 20-feet. Detailed information regarding the modeling assumptions used for the various source types can be found in the Appendix to the Risk Assessment Procedures. The HRA Tool includes the Emissions Calculator spreadsheet that can be used to upload Toxic Air Contaminant (TAC) emissions into the HRA Tool to calculate health risks instead of manually entering the TAC emissions. For some commonly permitted equipment, standard TAC emission factors are included in the Emissions Calculator. Detailed information regarding the emission factors included can be found here: Emissions Calculator Version 3 - References for Emission Factors (pdf, 493kb). Note that when a non-continuous operating schedule is entered in the HRA Tool (i.e. anything other than 24 hours/day and 7 days/week), this information is used to calculate the Worker Adjustment Factor (WAF) and does not affect or adjust TAC emissions entered.
If you have any questions or suggestions, please contact David Ono, Senior Air Quality Engineering Manager, at dono@aqmd.gov or (909) 396-2538.
For previous versions of the Risk Assessment Procedures, please visit the Risk Assessment Procedures Archive.
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