Air Toxics "Hot Spots" and Emissions Inventory Programs

The San Diego Air Pollution Control District prepares stationary source emission inventories for criteria pollutants and toxic air contaminants. Criteria pollutants are those that are regulated by air quality standards that were set using health-based criteria. Toxics air contaminants are those pollutants that cause or may cause cancer or other adverse health conditions even at extremely low levels, and some may accumulate in the body from repeated or chronic exposure.

The District is responsible for preparing air emissions inventory reports for facilities annually, biennially, or once every four years depending on the applicable requirements specified by Rule 19.3, CARB’s Criteria and Emissions Inventory Guideline Regulations and District policies. The emissions included in an inventory are typically from stationary emitting devices required to have District permits located at a regulated facility. Emitting devices that are permit exempt may also be included in the inventory. Emissions from mobile sources, natural sources and accidental releases are not included in the inventory. The District provides emission calculation procedures on how to quantify emissions from various devices.

There are two Emissions Inventory programs: the Criteria Pollutant Emissions Inventory (required by Rule 19.3) and the Toxic Emissions Inventory (required by California Health & Safety Code Sections 44300 - 44400 and CARB’s Criteria and Emissions Inventory Guideline Regulations). The Criteria Pollutant Emissions Inventory requires emissions of carbon monoxide (CO), lead (Pb), oxides of nitrogen (NOx), particulate matter (PM), oxides of sulfur (SOx) and volatile organic compounds (VOC’s) to be quantified. The Toxics Emissions Inventory or “Hot Spots” Program requires several listed toxic air contaminants to be quantified. Facilities subject to these programs are required to provide information to the District in order to identify and quantify emissions.

The District has a new web based program called EIS (Emissions Inventory System) to facilitate compiling the emissions inventory. EIS allows facilities to review their data request, provide required inventory information, and see their resulting inventory online. Facilities that are subject to emissions inventory requirements and wish to utilize EIS may contact the District’s Emissions Inventory Section to set up an account.

For the “Hot Spots” Program, once the toxic emissions are quantified, the District is required to prioritize and categorize the subject facilities to determine if a health risk assessment is warranted. The District utilizes a prioritization procedure which takes into consideration potency, toxicity, quantity of emissions and proximity of the facility to potential receptors and any other factor that the District finds may indicate that a facility poses a potential risk to receptors. The prioritization procedure categorizes the facilities as a high, intermediate or low priority. Facilities categorized as “high” are subject to health risk assessment (HRA) requirements. Facilities categorized as “intermediate” may be subject to HRA requirements. Facilities categorized as “low” are not subject to HRA requirements.

Facilities required to submit a HRA are no longer required to submit a HRA protocol for District review. The District will review and verify that the HRA was conducted in compliance with the HRA Guidelines adopted by the State Office of Environmental Health Hazard Assessment (OEHHA) and District’s "Hot Spots" Supplemental HRA Guidelines.