Air Toxics

Yolo-Solano AQMD’s Air Toxics Hot Spots Program requires certain facilities with the potential to emit certain amounts of toxic air pollutants to submit emissions inventories to the District and, in some cases, pursue risk reduction strategies.

The program is aimed at providing the public with information about potential health impacts from toxic air pollutants routinely emitted by facilities.

Districtwide Re-evaluation

The Office of Environmental Health Hazard Assessment (OEHHA) revised the Air Toxics Hot Spots Program Guidance Manual for the Preparation of Risk Assessments on March 6, 2015. The net result is that the calculated risk estimates for many sources have increased.

As a result of the change to the methodology, the District will be re-evaluating all facilities subject to the Hot Spots program.  The District held a public workshop on November 10, 2015 to discuss these changes. The District is sending out invoices to affected facilities, and will be collecting information necessary to calculate the prioritization scores for each facility.  If your facility is determined to be ‘low priority’ or ‘low risk’, there will be no additional invoices in future years.

Annual Report

State law requires districts to produce annual reports detailing local Air Toxics Hot Spots Program activities and facility listings.

2023 AB2588 Annual Report


The Air Toxics “Hot Spots’ Program was enacted by state law (AB 2588) in 1987.  The purpose of the law is to provide the public with information about the routine emissions and potential health impacts of toxic pollutants released to the air by facilities.

Certain facilities are subject to the program, and are required to submit a toxic emissions inventory.  With that data, the District calculates a prioritization score for each facility.  Depending on the prioritization score, some facilities are required to perform a health risk assessment.

Who is Subject to the Program?

State law defines the criteria which makes a facility subject to the program, including the following main categories of facilities:

  • Facilities with actual (criteria pollutant) emissions over 10 tons per year
  • Retail gas stations
  • Auto body shops
  • Facilities with diesel engines that operate more than 20 hours (from all engines combined) per year
  • Crop preparation services, if certain fumigants are used

For a full list of categories, and to determine whether your facility is identified as being subject to the program, see the District’s annual report above.