California’s guidelines for assessing the risk from air toxics have been revised. See more information on the Air Toxics Regulations page.
Air toxics are compounds in the air that have the potential to harm our health. People exposed to air toxics at higher concentrations and over time may have an increased chance of getting cancer or experiencing other serious health effects.
These health effects can include damage to the immune system, as well as neurological, reproductive (e.g., reduced fertility), developmental, respiratory, and other health problems.
People can be exposed to air toxics by:
- Breathing contaminated air.
- Eating contaminated foods, such as fish from contaminated waters; meat, milk, or eggs from animals that fed on contaminated plants; and fruits and vegetables grown in contaminated soil.
- Drinking contaminated water.
- Ingesting contaminated soil. Young children are especially vulnerable because they can ingest soil from their hands or from objects they place in their mouths.
- Making skin contact with contaminated soil, dust, or water.
Examples of air toxics include benzene, found in gasoline, asbestos, dioxin, toluene, and metals such as cadmium, mercury, chromium, and lead compounds. Air toxics come from cars and trucks and other mobile sources, stationary sources (business and industry sources), and indoor sources (for example, paints and solvents). Natural sources of air toxics include volcanoes and wildfires.
When we talk about health risk, we mean the probability, or chance, that exposure to a hazardous substance will make you sick. Everyone has the possibility of developing cancer or other illnesses. Our exposure to some substances can increase our chance of developing these illnesses — meaning we are more likely to develop them than someone who has not been exposed.
Scientists estimate the health risk by looking at:
- how hazardous the substance is, based on health studies; and
- how much of the substance people are being exposed to.
Risk assessment is what we call this process of estimating risk. In addition to looking at the amount and toxicity of the substance, risk assessments also look at other factors, including:
- weather conditions
- distance from the source of the substance to people
- the age, health, and lifestyle of people living or working near the source of the substance
- and the amount of time people have been exposed to the toxic substance.
It’s important to note that numbers provided by health risk assessments (known as HRAs) do not refer to actual cases of health problems that will occur from exposure to air toxics. The risk assessments are computer calculations that are a tool to identify and reduce possible negative health effects.
Increased cancer risk describes the increased chance of getting cancer from exposure to an air toxic. It’s expressed as a probability: the number of additional people that may get cancer in a group of one million people.
Non-cancer health risks can include acute, or short-term health problems such as eye irritation, respiratory irritation, and asthma episodes, and chronic, or long-term problems such as permanent damage to organs, the central nervous system, or reproductive functions, and developmental problems in children.
Non-cancer health risk is expressed as something called the “Hazard Index” (known as an HI). This is a way of comparing the increased health risk from exposure to the air toxic to a level that is considered acceptable to public health professionals. For example, a Hazard Index of 2 means the concentration of toxics in the air at the point of exposure is predicted to be twice as high as is generally thought to be safe.
Reducing Health Risk from Air Toxics
State and federal regulations are designed to control exposure to air toxics, and reduce the health risk. For more information, see Air Toxics Regulations. In Santa Barbara County, the District is responsible for implementing the California Air Toxics “Hot Spots” legislation. Through this program, affected facilities, with assistance from the the District, determine air toxic emissions. Facilities that release considerable amounts of toxic air pollutants are required to perform a risk assessment to estimate public health risks associated with these emissions. The District then oversees public notification and risk reduction programs required for facilities that pose a significant risk.
The current thresholds that define a significant risk from air toxics in Santa Barbara County, set and approved by the District’s Board of Directors, are: for cancer risk, a risk of equal to or greater than 10 in a million; and for non-cancer acute and chronic risk, a hazard index greater than 1.
Significant Risk Facilities
A significant risk facility is a facility operation that releases toxic substances into the air that pose health risks at levels that exceed the District’s thresholds.
Currently, there are no significant risk facilities in Santa Barbara County.
Over time, the District has worked with facilities to reduce their risk to under these thresholds. Since 1991, the number of significant risk facilities in Santa Barbara County has been reduced by 100 percent. In 1991 there were 51 significant risk facilities and now there are zero. In addition to evaluating existing facilities in AB 2588, the District evaluates health risk associated with new or modified facilities during the permit process when issuing new Authority to Construct permits. The goal for the District’s new source review health risk program is to prevent a new or modified facility from creating a significant risk to the community (using the significance criteria established by the AB 2588 program). With this program no additional significant risk facilities have been created since 1991.
For more technical information on requirements for Santa Barbara County facilities, see Air Toxics for Business.
For more general information on air toxics and your health see:
- Risk Assessment for Toxic Air Pollutants: A Citizen’s Guide
- California Air Resources Board Air Toxics Program Current Activities
For more information or assistance, please contact David Harris at (805) 961-8824 or at [email protected] (Air Toxics Section).