|
|
 |
|
The California Air Resources Board (ARB) developed CHAPIS as an Internet-based system which provides a simplified way to look at the size and spatial distribution of air pollution emission sources in California. ARB and local air pollution agencies collect criteria and toxic emission data from air pollution sources. This information is compiled to create the California Emission Inventory. Currently, the point source criteria and toxic pollutant emissions data from the 2001 California Emission Inventory are available in CHAPIS. The emission data mapped in CHAPIS represent a "snapshot" of the point sources contained in the 2001 ARB Emission Inventory database called CEIDARS. All of the reported mobile and area-wide emissions are reflected as gridded emissions layers in CHAPIS. For the point (industrial) sources, the data are being phased in by source categories to allow review and quality assurance, and only selected data categories are included to date. An effort was made to confirm the location of the reported point sources in the CEIDARS database. However, positional accuracy for triangle marker placement for facilities varies based on the accuracy of reported coordinates, and the accuracy and completeness of the address-matching criteria used to assign location. The data currently available in CHAPIS for point sources reflect reported emissions from approximately 1,800 individual facilities. For more information regarding the data included for facilities, refer to the point (stationary) source reference in this file. |
|
The first step is to choose an
administrative boundary (i.e. a County, Air Basin,
Air District, or Zip Code), or region of interest. This can be accomplished from the CHAPIS
launch page by using either the drop-down menus, the "clickable" map of
California, or by entering a zip code into the textbox provided and pressing
the "Find Zip" button. The main CHAPIS web page returns with
additional choices and a map that shows all of the point sources within
the selected boundary (which is highlighted in yellow) as well as surrounding
areas. |
|
 |
| The
Map Panel is where the map image is displayed. The map is interactive, and
using the Map Tools you can zoom in and
out on the map, pan around the map, or identify map features.
The information displayed on the map is dependent on:
As you zoom in on the map you will reveal more detail in the form of additional data. This is due to the presence of scale-dependent map layers. Map layers that show a great amount of detail often have pre-set scales at which they become visible. This is to prevent the data from obscuring the map at small (statewide) scales. Use the Zoom In tool to increase the scale of the map until these layers are visible. The map scale is displayed with a scale bar at the bottom left-hand corner of the map, and the message area below the map indicates the width of the map in miles. |
|
|
CHAPIS has three "message areas" for displaying Tool Tips, Map Feature Labels (Hover Labels), and miscellaneous messages about the results of analyses. Tool Tips are messages about the usage of the map tools found in CHAPIS. When your mouse pointer hovers over any of the tools, the name of the tool will be displayed in the Tool Tip message area, found directly above the toolbar. When you click on a tool to select it, the Tool Tip message area displays a message about the usage of the selected tool, as shown below for the Zoom In tool. This message is always displayed in red, and persists in the Tool Tip message area to serve as a reminder of which tool is currently selected. |
 |
|
|
Hover Labels are messages that display attribute information about features on the map (in most cases it is the feature's name). This functionality is only available for a selected set of map layers - available layers are listed in a drop-down menu below the map - and works for only one layer at a time. To view Hover Labels, simply hover your mouse over a feature on the map. The name of the feature will appear in the Hover Label message area, directly above the map. If a Hover Label does not appear, it may be because:
|
|
Miscellaneous Messages
The message area on the upper right-hand side of the web page is used to display a variety of messages, including the number of results returned by the Identify tool, the distance measured by the Measure tool, and warnings about Zip Codes that could not be found. |
 |
|
|
The map displayed on this web site is composed of a number of stacked data "layers". A layer can be thought of as a collection of features with a common theme. For example, all of the State of California's major highways are contained on a single layer, as are the state's cities, major water bodies, schools and so on. You can view a list of the map's layers by clicking the button labeled "Show Layer List". Clicking this button produces a pop-up window like the one shown on the right. Each layer has an associated "check box" which indicates the layer's visibility - layers with a checkmark are currently visible on the map. Check boxes can also be used to turn a layer's visibility on or off . To check, or un-check a box, simply click the box with your mouse pointer. To submit changes you have made to layer visibility click the "Refresh Map" button found at the bottom of the window. This functionality gives you the ability to customize the map's appearance, displaying only the layers you want to see. At times the layer list will include layer names that are grayed-out. This indicates that the layer's visibility is controlled by scale-dependency. When the map scale is within the layer's upper scale threshold the layer name will no longer be grayed-out, and you will be able to control it's visibility via a check-box. |
 |
|
|
The toolbar is located directly above the map and is comprised of a number of icons, each representing a map tool. The tools have been organized by functionality into the following groupings: Navigation, Analysis, and Overview Map. For instructions on how to use the tools refer to the relevant sections below. To select a tool from the toolbar, simply click on the tool icon with your mouse pointer. Once a tool has been selected you will notice that a red box appears around it's icon; this indicates that it is the currently selected tool. |
|
|
|
|
| Directly below the map you will find two drop-down menus, the first of which contains a list of toxic and criteria pollutants. With this list, search criteria can be established to view only those sources emitting a selected pollutant. |
 |
|
Press the black arrow on the right side of the "Select a pollutant" menu to choose a pollutant to map. Before any changes take place on the map you must submit your selection by pressing the "Go" button. Industrial (point) emissions source locations are marked using a black triangle. When a pollutant is selected the point markers are replaced with a graduated symbol that reflects the amount of emissions reported for each facility. A legend is available on-screen to identify the range of emissions associated with the marker size. |
 |
|
The second drop-down menu contains a list of Standard Industrial Classification (SIC) codes. With this list, search criteria can be established to differentiate between those facilities whose SIC code matches that selected, and those that do not. When a SIC code is selected only those facilities having the selected SIC code are symbolized with a black triangle - facilities with a different SIC code are "grayed-out". Once a pollutant or a SIC code has been selected, a button labeled "Clear" will appear beside the menu. Pressing this button will clear the currently selected pollutant and/or SIC code, and refresh the map |
|
| At the bottom of the CHAPIS
web page you will find two drop-down menus, and a text box where you can enter a
zip code. These features allow you to quickly zoom to an area of interest to you. |
| The first drop-down menu contains a list of all 58 counties in the state of California, as well as the State's 15 recognized Air Basins, and 35 Air Districts. Each category is indicated by a heading. If, for instance, you are interested in the air quality of Fresno county, you could quickly zoom to the extent of the county by selecting Fresno from the COUNTIES section of the drop down-menu . Selecting a name automatically redraws the map to your chosen extent. |
| The second drop-down menu contains a list of 17 regions of interest in the state of California. Selecting a name automatically redraws the map to your chosen region. |
| The text box allows you to enter a zip code to zoom to. Once you have finished entering your zip, press the button labeled "Go To Zip". If the zip code is found, the map will be redrawn, zoomed-in to the geographic boundaries of your zip code. |
|
|
|
|
|
 |
A facilities legend is displayed to the right of the map. This legend is used only to display the symbology of industrial (point) emissions sources. This legend changes to reflect the current settings (i.e. whether a pollutant or SIC code has been selected from the drop-down menus at the top of the page). If a pollutant hasn't been selected, facilities are uniformly symbolized with a black triangle. Once a pollutant has been selected from the menu, the symbology changes to a black, graduated triangular symbol (pictured on left). |
| To view an expanded legend for all other map layers, click on the "Show Full Legend" button, found directly to the right of the facility legend. A map legend showing the symbology for all of the visible layers (pictured on right) is displayed in it's own browser window. |  |
|
|
This section provides definitions of some of the terms used in the CHAPIS application. Air BasinsCalifornia is divided geographically into air basins for the purpose of managing the air resources of the State on a regional basis. Areas within each air basin are considered to share the same air masses and are therefore expected to have similar ambient air quality. The State is currently divided into 14 land-based 6air basins, along with an Outer Continental Shelf (OCS) ocean-based air basin, which is sometimes included.
Air DistrictsThe State is divided into 35 Air Pollution Control Districts and Air Quality Management Districts, which are also called local air districts. These agencies are county or regional governing authorities that have primary responsibility for controlling air pollution from stationary sources
Cancer Potency Weighted PoundsA relative index used to normalize for the widely differing toxicities (cancer potencies) of different air toxic chemicals on a pound-for-pound basis. The pounds of emissions of each carcinogenic chemical are weighted by the relative cancer potency value for that chemical. Potency-Weighted Lbs = Emissions of Pollutant (in lbs) x Cancer Potency Value
for that Pollutant x 1700.
Criteria Air PollutantCriteria air pollutants are those pollutants, and their precursors, for which health-based threshold standards (or "criteria") have been promulgated by the federal or state air agencies. The staff at the California Air Resources Board compiles data to create the criteria pollutant emission inventory which includes information on the emissions of reactive organic gases (ROG), oxides of nitrogen (NOx), oxides of sulfur (SOx), carbon monoxide (CO), and particulate matter (PM10).
Area-wide (Dispersed) Sources of Emissions
Area-wide sources include widely dispersed sources such as the use of consumer products (hairspray, home automotive products, home cleaners, etc.) and other dispersed solvent uses, such as painting (sometimes referred to as architectural coating). Area-wide emission sources are generally estimated at a county-level of resolution, then spatially allocated to smaller grid squares using spatial allocation factors that are based on a surrogate for the activity, such as using the distribution of population to allocate consumer product usage.
Emission InventoryThe California Air Resources Board has collected information on emissions from air pollution sources since 1969. This information is periodically compiled by State and local air pollution control agencies to create an emission inventory; an important building block in the development of the State's air pollution control program. The emission inventory includes information on the emissions of criteria and toxic air pollutants. Criteria pollutants include reactive organic gases (ROG), oxides of nitrogen (NOx), oxides of sulfur (SOx), carbon monoxide (CO), and particulate matter of diameter 10 microns or less (PM10). Toxic data available within CHAPIS were collected in response to Assembly Bill (AB) 2588 (Connelly), the Air Toxics "Hot Spots" Information and Assessment Act. Criteria and toxic data are gathered on an ongoing basis and stored in the California Emission Inventory Development and Reporting System (CEIDARS).
Gridded EmissionsGridded emissions are used as a common basis for combining all source categories onto one map view. The state is divided into a set of grid squares, which are one or more kilometers on a side. Any emissions that fall into a particular grid square add to the total emissions and corresponding color used for that grid cell on the map. Traditionally, most mobile and area-wide source categories are inventoried only as county-total emission estimates. So these county totals must be spatially distributed to the smaller grid areas using spatial surrogates to apportion the emissions for each source category type. For example, the distribution of population (based on the census) is used to allocate the consumer product (household) emissions into grid cells.
Mobile Sources of Emissions -- On-Road Mobile and Off-Road Mobile SourcesMobile sources can be either on-road or off-road mobile sources. On-road mobile sources include motor vehicles that customarily carry passengers or freight, and operate on public roads, such as cars, trucks, buses, and motorcycles. Off-road mobile sources include trains, ships and boats, airplanes, cranes, construction equipment, lawn mowers, and leaf blowers.
Point (Stationary) Sources of Emissions -- Industrial and Small Commercial Facilities
The point, or stationary, sources of emissions include
businesses and manufacturing facilities operating at a fixed location. Large industrial point sources include industrial or
manufacturing facilities, such as electric power plants or refineries. The information is compiled
by each local air pollution control or air quality management district, usually through
permits, throughput surveys, or other reporting requirements. The emissions are generally
available for these sources for the site location of the industrial facility, so these
sources can be represented both as triangular symbols on the CHAPIS map and
also summarized into grid cells. Small commercial point sources include relatively
small, widespread businesses, such as gasoline stations, dry cleaners, or
autobody shops. The information is
sometimes available from the districts for individual sites that can be
represented as point sources, or more often are estimated only as county-total
emission estimates that are spatially allocated to grid cells using surrogates.
The information currently available in CHAPIS reflects
reported emission data from approximately 1,800 industrial facilities as point
sources. The point sources are being phased in over time by selected source categories, to allow
for review and quality assurance. (See “Selected Data”
for more information on which source categories are included). To best represent the geographic
location of industrial point sources, an effort was made to assess the accuracy of a facility’s
reported geographic coordinates. Where geographic coordinates were determined to be reasonably
accurate, these coordinates were used to assign geographic location. When coordinates were found to
be incomplete or inaccurate, and if facility address, city, and zip code information was determined to be
accurate and sufficiently complete, then geographic location was assigned based
on matching reported facility addresses to map address ranges.
Selected DataCHAPIS includes all of the on-road and off-road mobile sources, and all of the area-wide sources, as gridded emissions. For the point (stationary) sources, represented as triangles on the CHAPIS map, the facilities are being phased in over time by source categories to allow for review and quality assurance. To date, CHAPIS includes the following stationary source (facility) information: 1. Criteria air pollutant emissions from facilities that emit 10 or more tons per year of ROG, NOx, SOx, CO, or PM10;2. Toxic air pollutant emissions from power plants (50 megawatts or more) and refineries; and 3. Toxic air pollutant emissions from facilities that conducted health risk assessments under the Air Toxics “Hot Spots” Program and fall into the categories of (a) metal fabrication facilities, (b) aerospace/electronics facilities, and (c) chemical plants. The ARB is continuing to collaborate with the California Air Pollution Control Officers Association (CAPCOA) regarding the inclusion of additional toxics emission facilities. Over the next several months we anticipate adding information for the other facilities that conducted health risk assessments, as well as locations of gasoline stations and other small commercial categories.
Standard Industrial Classification (SIC) CodeA statistical classification standard underlying all establishment-based federal economic statistics classified by industry. The SIC two-digit summary group classification is used in CHAPIS.
Toxic Air PollutantToxic air pollutants are chemicals that have the potential to cause adverse health effects, such as cancer, birth defects, and organ damage. Toxics emission inventory data included in CHAPIS are from the 2001 database year of the CEIDARS emission inventory and reflect the most current data available. However, the emissions in the database may be derived from earlier or more recent emission inventory reporting years. The toxics data are submitted to the ARB by the air pollution control and air quality management districts as a requirement of the Air Toxics "Hot Spots" Program (sometimes referred to as AB 2588). The "Hot Spots" Program requires emission inventory updates every four years for the larger facilities if there have been substantial increases in their previously reported emissions. Toxic air contaminants are also identified and controlled through the Toxic Air Contaminant Identification and Control Program (sometimes referred to as AB 1807). |
.
