CHAPIS Emissions Maps
More About the Data
Mobile, Stationary, and Area-wide Sources
The information displayed in CHAPIS comes from three major areas:
mobile sources,
stationary sources, and
area-wide sources.
The mobile sources include information on cars and trucks
(on-road mobile)
as well as other mobile sources, like off-road equipment, construction equipment, ships,
trains, and airports. The information for
cars and trucks is compiled by the Air Resources Board (ARB) using
information from ARB testing and research, the
Department of Motor Vehicles (DMV), the California Councils Of
Government (COGs), and Caltrans. Various models,
including EMFAC2002 and Travel Demand
Models, are used to estimate emissions annually of cars and
trucks. County-total estimates are spatially allocated to smaller grid
cells using the Direct Travel Impact Model
(DTIM). For other (off-road) mobile sources, the ARB's OFFROAD model is
used to estimate emissions. County-totals
are spatially allocated to smaller grid cells using spatial surrogate
distributions, such as light commercial zoning.
The stationary sources include information on businesses and
manufacturing facilities and is compiled by each local
air district. These sources are shown as black triangles in CHAPIS, and
are also included as one of the source
types in the Gridded Emission combinations. Larger industrial or
commercial facilities can be viewed separately
from the small commercial facilities (which include county-wide,
aggregated estimates for facilities like gas stations
and dry cleaners) in the Gridded Emissions checklists.
The area-wide sources include consumer products, paints, and other
products containing solvents. These sources
are estimated annually by the Air Resources Board and/or the local air
districts. County-totals are spatially distributed
using surrogate distributions (such as population for consumer
products).
To view the information on mobile sources and area-wide sources, use
the "Gridded Emissions" button in
CHAPIS. The totals from all source types can be combined, or they can
be turned on and off separately, for example
to view just the contribution of cars and trucks (on-road mobile
sources) to the emissions in each grid cell.
More Information on Stationary Sources
For stationary sources (industrial and commercial facilities), two
broad types of pollutants are inventoried in
California. The first type includes the traditional, smog-forming
pollutants (called "criteria pollutants"),
and includes reactive organic gases (ROG), nitrogen oxides (NOx),
sulfur oxides (SOx), particulate matter (PM10),
and carbon monoxide (CO). These emissions are estimated annually by the
local air districts for major stationary-source
facilities in their area. Currently, CHAPIS includes criteria pollutant
data for facilities that emit 10 or more
tons per year of any criteria pollutants. The second type of pollutant
includes the toxic air pollutants, that
can cause or contribute to adverse health effects, such as cancer,
chronic organ damage, or reproductive harm.
Most of the stationary source toxics information in CHAPIS is collected
under a state law for the Air Toxics
"Hot Spots" program, enacted
in 1987. The "Hot Spots" program is intended
to identify facilities whose toxic air pollution emissions may pose
local impacts. The "Hot Spots" legislation
requires facilities (stationary sources) to report to their local air
district information about the toxic air
pollution released from routine operations of the facility. Currently,
CHAPIS includes toxics data for petroleum
refineries, power plants over 50 megawatts, as well as metal
fabrication facilities, aerospace/electronics manufacturing
facilities, and chemical plants that conducted risk assessments under
the "'Hot Spots" program. There
will be on-going additions to the toxics data in the future.
After receiving the air toxics inventory information, the local air
district prioritizes the facility into
"low", "medium", or "high" priority, and the highest priority
facilities must conduct
a health risk
assessment. The prioritization scores themselves are not an
accurate measurement of risk; rather, they are used to determine whether a
facility must conduct a more refined risk assessment.
This risk assessment is then reviewed by the State of California Office
of Environmental Health Hazard Assessment
(OEHHA), and approved by
the local air district. If the risk from that facility is significant,
the operator of that facility must notify the public of the
risk posed by that facility. For example, the facility may place ads in local
newspapers, or conduct a community meeting to discuss
the risks posed by that facility. If the risk exceeds a
risk threshold, that facility
is also required to reduce those risks below a level of significance
set by each local air district. This notification
requirement has proven effective in voluntary reductions of thousands
of pounds of toxic emissions from facilities
throughout the state.
Every four years, facilities are required to submit an update of their
emissions (an emission inventory) to the local
air district. Often the facility has not changed their business
significantly in the past four years and simply
states that there is "no change". Please contact the local
air district for the most recent
emission and risk data. For a detailed discussion of the "Hot Spots"
program, please click here. Use the district
links at the bottom to read more about your local air district's toxics
program and/or link to the local air district's "Hot Spots" annual
report.
To date, CHAPIS includes the following stationary source (facility)
information:
1. Criteria pollutant emissions, from facilities that emit 10 or more
tons per year of reactive organic gases (ROG),
nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide (CO), or
particulate matter of 10 microns or less (PM10).
2. Toxic pollutant emissions from Power Plants (50 megawatts or
greater) and Refineries.
3. Toxic pollutant emissions from facilities that conducted health risk
assessments under California's Air Toxics
"Hot Spots" program in the categories of chemical manufacturing, metal
fabrication, and aerospace/electronics
manufacturing.
CHAPIS uses the facility data reported in ARB's
CEIDARS database for the
year 2001. The latest snapshot of CEIDARS for CHAPIS was May 19, 2004.
The initial release includes facilities emitting the bulk of the
criteria pollutant (smog-forming) emissions and
many of the larger or important sources of toxic air pollutants.
However, overall at this time, there is a much
lower number of facilities with toxic air pollutant information in
CHAPIS than for criteria pollutants. It is a
major objective of CHAPIS to include all of the largest air pollution
sources and those with the highest documented
air pollution risk. CHAPIS will be updated on a periodic basis and
additional facilities will be added to CHAPIS
as more data become available.
Future Additions:
We are continuing to collaborate with the local air districts through
the California Air Pollution Control Officers
Association (CAPCOA) regarding the on-going inclusion of additional
toxics emission facilities. In a few months
we anticipate adding information for the following types of facilities:
(a) Other facilities with "Hot Spots" risk assessments
(b) Gas stations
(c) Plating industry
(d) Dry cleaners
Community Health | Emission Inventory
This page last reviewed May 13, 2008
