What are air toxics?
Do APCDs monitoring stations monitor air toxic levels?
Does anyone monitor air toxics levels?
What do the data from the downtown Santa Barbara station show?
How are air toxics regulated in Santa Barbara County?
Who must comply with the "Hot Spots" Act?
What are the requirements of the "Hot Spots" Act?
What do we mean by "risk?"
How do we determine who is at risk?
What is a "significant risk" facility?
What are the significant risk facilities in Santa Barbara County?
Air toxics are chemicals released into the air that are known or suspected to cause
cancer, or other serious health problems, such as birth defects or reproductive
effects. The federal Clean Air Act, as amended in 1990, lists 188 of these materials,
called hazardous air pollutants. California air toxics legislation lists
729 of these substances, referring to them as toxic air contaminants. Some examples
of air toxics include: benzene, butadiene, formaldehyde, and hydrogen sulfide.
No. Typically local district monitoring station networks are set up to meet
federal and state requirements to monitor levels of six pollutants (called
"criteria" pollutants): nitrogen oxides (NOx), sulfur dioxide, particulate
matter, carbon monoxide, lead, and ground-level ozone.
There is little hard data available on monitored levels of air toxics. The
California Air Resources Board has 21 air toxics monitoring stations around the state,
but recently closed the only such station in Santa Barbara County, which was
located in downtown Santa Barbara. The United States Environmental
Protection Agency (USEPA) has begun a pilot project setting up air toxics monitors and may
be more active in this area in coming years.
The data from the now-closed toxics monitoring station show a downward trend in levels of toxics, particularly toxics found
in vehicle exhaust. From 1990 to 1996, levels of benzene decreased by 76%, and levels of
1,3-butadiene decreased by 50%. There are also downward trends in levels of
perchloroethylene (used in dry cleaning) and hexavalent chromium (an industrial
Air toxics are emitted by mobile sources (cars, trucks, trains, and vessels), stationary sources
(industrial facilities) and area sources (natural sources, and a variety of products such
as paints or household cleaners). In California, emissions from mobile sources are
regulated by the USEPA and the state Air Resources Board.
APCDs air toxics program tracks toxic air emissions from stationary sources. APCD
also develops "industry-wide" toxic emission inventories for smaller stationary
sources, such as dry cleaners and gasoline stations. The APCD program was set up to
implement and enforce the California Air Toxics "Hot Spots" Information and
Assessment Act, signed into law in 1987. This Act, also known as AB 2588, requires
businesses and industries throughout the state to:
--quantify (inventory) and report their emissions of some 729 listed air toxics;
--assess the possible health risks from their emissions;
--notify members of the public who are exposed to significant risks attributable to their
--take steps to reduce this risk.
When Congress amended the federal Clean Air Act in 1990, it expanded the scope of air
toxics regulation by adding provisions to develop control standards for hazardous air
pollutants (HAPs). These standards are called Maximum Achievable Control Technology
(MACT) standards. States and local agencies such as APCD are responsible for implementing
and enforcing the MACT standards, which require the use of control
technologies to achieve emission reductions in industries that are
major sources of HAPs (such as the aerospace or oil and gas industries), as well as in
facilities that make up area sources of HAPs (such as dry cleaners). APCD's program
to enforce the federal provisions, commonly known as Title III, is not as fully developed
as its toxics "Hot Spots" program, but will be a focus in the future.
The Air Toxics "Hot Spots" Act requires the California Air
Resources Board (ARB) to maintain a list of toxic air pollutants that may
cause adverse health affects. The list is contained in Appendices A-I and A-II
of the ARBís Air Toxic "Hot Spots" Emission Inventory Criteria and
Guidelines Regulation (CGR). The list, which is updated annually, contains
chemicals that have been shown to cause adverse health effects.
A business is subject to the Act if:
- The business manufactures, formulates, uses, or releases any listed
substance, or any substance that reacts to form a listed substance; or
- The business is included in a current list of air toxic sources prepared
by the APCD.
Businesses that use or emit one or more listed toxic air contaminant must report
their emissions of each listed substance. For most small businesses, this is
accomplished by completing a questionnaire which includes information on the
type and quantity of materials that they use. The APCD then develops
industry-wide inventories of air toxics based on the information provided.
When introduced into the program, larger or more complex businesses are
required to submit to the APCD a Toxic Emissions Inventory Plan which
describes the methods they will use to calculate their toxic air emissions.
Once this plan is approved, the businesses prepare and submit a Toxic
Emissions Inventory Report which quantifies their actual toxic emissions.
2. Risk Assessment
Based on the type and quantity of toxic air pollutants emitted, the APCD ranks
each business according to their potential to cause a public health risk.
Businesses with a medium or high risk potential are required to complete a
health risk assessment. A risk assessment estimates the probability of people
contracting cancer or other illnesses from exposure to toxic air contaminants.
The APCD has developed a computer model to prepare risk assessments, and will
perform this service at no additional cost if requested by the business. With
the APCD performing this task, business costs are greatly reduced.
3. Public Notification
If results of the risk assessment show that a business poses a significant
public health risk, then the business must notify residents in the surrounding
area of this risk. Businesses will be required to notify people in writing,
and may be required to hold a public meeting to educate the community. APCD
staff will also be available to answer questions.
4. Risk Reduction
In addition to public notification, a business found to pose a significant
public health risk will be required to take steps to reduce that risk within 5
years. To attain this goal, the business must perform an audit to identify
changes in operations that will reduce toxic emissions and the associated
risk. The business must submit for APCD review a Risk Reduction Plan that
includes measures which will be implemented to reduce the health risk from
their facility emissions.
Small businesses that are part of an industry-wide inventory, such as gas
stations, dry cleaners and auto body shops, complete a questionnaire every
year as part of the annual report required by their permit.
Businesses that prepare a Toxic Emissions Inventory Plan and Report submit
updated information every four years. The update requirements depend upon the
risk attributable to the business and the business operations. Businesses that
pose a significant health risk must submit an updated Plan and Report every
four years. Lower risk facilities must only complete an update summary form.
Based upon review of this form, the APCD will notify those facilities that
are expected to have a considerable change in their toxics emission inventory
of the need to submit an updated plan and report.
Risk refers to the increased potential for negative health effects posed by exposure of
individuals to toxic emissions. The risk posed by a particular toxic air
contaminant can be a cancer
risk or a non-cancer risk, or both. Non-cancer risk can be acute, meaning effects can be
felt in a relatively short time after exposure to the substance, or chronic, meaning
effects are cumulative from exposure over an extended period of time. Risk assessments are
done to estimate the increased risk posed by toxic emissions. Toxic substances
can enter the
body through multiple pathways, including inhalation (breathing), dermal
contact (touching), and ingestion (eating and drinking). The health risk
assessment is crafted to account for these pathways. For more information see
Risk Facilities/Explanation of Risk.
For facilities that emit significant amounts of air toxics, something known as
a risk "isopleth" or "footprint" is developed. This is a map that
shows the area of elevated risk around the facility. It is developed taking into account
prevailing winds and weather conditions in the area. In some cases the risk
be so small that no one is actually living in the affected area.
Risk assessment results for cancer-causing air toxics are given in terms of the
probability that an individual will contract cancer (usually expressed as so many chances
in a million). For non-cancer risk, a "Hazard Index" is used. A Hazard Index
presents the ratio of the predicted exposure level of a toxic pollutant to the level
of exposure considered acceptable by health professionals. If the Hazard Index is more than 1.0, it is considered a significant risk
facility (see below). Typically for non-cancer risk the "endpoint" is also
identified. This is the part of the body most affected by the particular
Background risk is the risk level found throughout an area. This risk is not caused by
a particular facility, and may be partly due to air pollution from vehicle traffic. The
estimated background cancer risks due to air pollution for some selected areas of Santa
Barbara County are as follows:
|Downtown Santa Barbara:
||524 cancer cases per million
||98 cancer cases per million
||47 cancer cases per million
||40 cancer cases per million
For more information, see
Risk Facilities/Putting Risk into Perspective.
For cancer risk, if a facilitys toxic air emissions result in a cancer
risk of equal to or greater than 10 in a million, it is considered a significant risk
facility. For non-cancer risk, if a facilitys toxic air emissions result
in a Hazard Index equal to or greater than 1.0, it is considered a significant risk
facility. Significant risk facilities are required to reduce their risk, and to notify
people living in the risk footprint about the elevated risk. See Significant
The sources that currently exceed the significant risk thresholds of cancer,
chronic non-cancer, and acute non-cancer may be found at the following link
County's Significant Risk Facilities.