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Outdoor Air Quality - Fine Particulate Matter:
Daily Fine Particulate Matter (PM2.5) (µg/m³)
Years 2003 - 2008
Summary
The Outdoor Air Quality - Fine Particulate Matter data available on CDC WONDER are geographically aggregated daily measures of fine particulate matter in the outdoor air, spanning the years 2003-2008. PM2.5 particles are air pollutants with an aerodynamic diameter less than 2.5 micrometers. Reported measures are the daily measure of fine particulate matter in micrograms per cubic meter (PM2.5) (µg/m³), the number of observations, minimum and maximum range value, and standard deviation. Data are available by place (combined 48 contiguous states plus the District of Columbia, region, division, state, county), time (year, month, day) and specified fine particulate matter (µg/m³) value. County-level and higher data are aggregated from 10 kilometer square spatial resolution grids.
Source:
In a study funded by the NASA Applied Sciences Program / Public Health Program (fully cited below), scientists at NASA Marshall Space Flight Center / Universities Space Research Association modified the regional surfacing algorithm of Al-Hamdan et al. (2009) and used it to generate continuous spatial surfaces (grids) of daily PM2.5 for the whole conterminous U.S. for 2003-2008. Two sources of environmental data were used as input to the surfacing algorithm, US Environmental Protection Agency (EPA) Air Quality System (AQS) PM2.5 in-situ data and National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth remotely sensed data. They also identified in a Geographic Information System (GIS) the associated geographic locations of the centroids of the gridded PM2.5 dataset in terms of the counties and states they fall into to enable aggregation to different geographic levels in CDC WONDER. See also Data Source Information.
In WONDER: You can produce tables, maps, charts, and data extracts. Obtain average fine particulate matter (µg/m³), the number of observations, range, and standard deviation. Select specific criteria to produce cross-tabulated average fine particulate matter (µg/m³)measures. Data are organized into three levels of geographic detail: the 48 contiguous states, state (including multi-state regions and divisions) and county. County-level data are aggregated from 10 kilometer square spatial resolution grids. You can limit and index your data by any and all of the variables. Contents: PM2.5 Data Request
Data Source Information
Additional Information
PM2.5 Data Request
Output You can produce tables, maps, charts, and data extracts. Obtain average fine particulate matter (µg/m³), the number of observations, range, and standard deviation. Select specific criteria to produce cross-tabulated fine particulate matter measures. Data are organized into three levels of geographic detail: the 48 contiguous states, state (including multi-state regions and divisions) and county. You can limit and index your data by any and all of the variables. Variables You can limit and index your data by any and all of these variables:
- Location: Region, Division, State, County
- Year: 2003-2008
- Month: January - December, available also as specific "Month, Year" values
- Day: Available as specific "Month Day, Year" values, or as Day of Month (1-31) or as Day of Year (1-366)
- Fine Particulate Matter (µg/m³): 0 to >=65
How? The Request screen has sections to guide you through the making a data request as step-by-step process. However, to get your first taste of how the system works, you might want to simply press any Send button, and execute the default data request. The data results for your query appear on the Table screen. After you get your data results, try the Chart and Map screens. Or export your data to a file (tab-delimited line listing) for download to your computer.
For more information, see the Quick Start Guide and the following steps:'By-Variables' Select variables that serve as keys (indexes) for organizing your data. See "How do I organize my data?" for more information.
Note: To map your data, you must select at least one geographical location as a "By-Variable" for grouping your data, such as State or County.Help Click on any button labeled "Help", located to the right hand side of the screen at the top of each section. Each control's label, such as the "Location" label next to the Location entry box, is linked to the on-line help for that item. Send Sends your data request to be processed on the CDC WONDER databases. The Send buttons are located on the bottom of the Request page, and also in the upper right corner of each section, for easy access.
Step 1. Organize table layout:
Group Results By Select up to five variables that serve as keys for grouping your data. See Group Results By below for hints. Optional Measures The Average fine particulate matter (µg/m³) measures for the specified time and place are reported by default. If checked, these optional measures will also appear in the results table.
- Number of observations, how many measurements went into the average daily fine particulate matter statistic
- Range or minimum - maximum values for the average fine particulate matter statistic
- Standard deviation for this summary statistic
Title Enter any desired description to display as a title with your results.
Group Results By...Select up to five variables that serve as keys for grouping your data. For example, you could select to group (summarize, stratify, index) your data by State and by County.
How? See "How do I organize my data?" for more information.Hints:
- About charts:
You cannot make charts when your data has more than two By-Variables.- About maps:
To make a map, you must request data with a geographic location variable, such as Region, as the first "By-Variable" in the "Group Results By" box. Send your data request, then click the Map tab when you get the results.
Average Fine Particulate Matter (µg/m³)The average daily fine particulate matter summary measure is the mean value of all of the daily outdoor air fine particulate matter (PM2.5) (µg/m³) values that met the selected query criteria. For example, if results are grouped by Year and limited to the South Region for years 2003-2008, then the first row shows the value 12.35 (µg/m³) as the average fine particulate matter value for year 2003 in the South Region. This summary measure is the mean of the daily values recorded for fine particulate matter (PM2.5) (µg/m³) estimates of the 10 kilometer square spatial resolution geographic-area grids in the selected time and place.
How? This summary measures is reported by default for all queries.Notes:
- The average measurement is the mean value of all of the daily values that met the selected criteria for time and place.
- This dataset contains daily fine particulate matter (PM2.5) (µg/m³) estimates of outdoor air quality. PM2.5 particles are air pollutants with an aerodynamic diameter less than 2.5 micrometers. The values are summarized to the county-level, from 10 kilometer square spatial area grids covering the 48 contiguous United states (not including Alaska and Hawaii) plus the District of Columbia.
- Fine particulate matter estimates are recorded for 10 kilometer square spatial resolution grids in the selected area. PM2.5 estimates from each grid are assigned to the county where the grid centroid is located. WONDER shows the summary the grid-level estimates into counties and larger areas. The county locations are from the 1999-2000 Federal Information Processing (FIPS) code set.
Number of ObservationsThe number of observations is the number of daily fine particulate matter values that produced the summary measure. For example, for January 1, 2008, there were 80,650 fine particulate matter values averaged to produce the national average fine particulate matter value of 8.15 (µg/m³). The observations are the daily fine particulate matter values recorded for the 10 kilometer square spatial resolution grids in the selected time and place.
How? Select the checkbox labeled "# of Observations" under the "Optional Measures" heading in section 1. Organize table layout on the Request Form.Notes:
- The number of observations is the total number of daily fine particulate matter values recorded for the 10 kilometer square spatial resolution grids in the selected time and place.
- This dataset contains daily average fine particulate matter estimates. The values are summarized to the county-level, from 10 kilometer square spatial area grids covering the 48 contiguous United states (not including Alaska and Hawaii) plus the District of Columbia.
- MODIS fine particulate matter measurements are recorded for 10 kilometer square spatial resolution grids in the selected area. Measurements from each grid are assigned to the county where the grid centroid is located. WONDER shows the summary the grid-level estimates into counties and larger areas. The county locations are from the 1999-2000 Federal Information Processing (FIPS) code set.
RangeThe range shows the minimum and maximum measurements for the criteria that defines the cell in the table, from all of the grid-level estimates that contribute to the spatial average daily measurement. For example, when data are grouped by year and limited to the District of Columbia, for the 732 grid values of daily fine particulate matter in year 2008, the lowest value was 3.00 and the highest value was 34.50 (µg/m³).
How? Select the checkbox labeled "Range" under the "Optional Measures" heading in section 1. Organize table layout on the Request Form.Notes:
- The range shows the lowest and the highest values in the set that defines the average fine particulate matter measurement in the table cell, in the format: (minimum - maximum). Daily values are recorded for 10 kilometer square geographic-area grids in the selected time and place.
- This dataset contains daily average fine particulate matter estimates. The values are summarized to the county-level, from 10 kilometer square spatial area grids covering the 48 contiguous United states (not including Alaska and Hawaii) plus the District of Columbia.
- Fine particulate matter estimates are recorded for 10 kilometer square spatial resolution grids in the selected area. Measurements from each grid are assigned to the county where the grid centroid is located. WONDER shows the summary the grid-level measurements into counties and larger areas. The county locations are from the 1999-2000 Federal Information Processing (FIPS) code set.
Standard DeviationThe standard deviation shows the variance from the average or mean value that occurs in the grid-level values that meet the place and time criteria that define the table cell. A low standard deviation value is close to the mean, and a high standard deviation value indicates the data are spread of large range of values. For example, for the District of Columbia in 2008, for the 732 values of daily fine particulate matter, which ranged from 3.00 - 34.50 (µg/m³), the standard deviation from the average value of 12.40 (µg/m³) was 6.21 (µg/m³).
How? Select the checkbox labeled "Standard Deviation" under the "Optional Measures" heading in section 1. Organize table layout on the Request Form.Notes:
- The standard deviation shows the variance from the average or mean value that occurs in the grid-level values in the set that defines the average fine particulate matter measurement in the table cell. Daily values are recorded for 10 kilometer square geographic-area grids in the selected time and place.
- This dataset contains daily average fine particulate matter estimates. The values are summarized to the county-level, from 10 kilometer square spatial area grids covering the 48 contiguous United states (not including Alaska and Hawaii) plus the District of Columbia.
- Fine particulate matter measurements are recorded for 10 kilometer square spatial resolution grids in the selected area. Measurements from each grid are assigned to the county where the grid centroid is located. WONDER shows the summary the grid-level measurements into counties and larger areas. The county locations are from the 1999-2000 Federal Information Processing (FIPS) code set.
Select the place of interest:
- Location: the 48 contiguous United States plus District of Columbia by Region, Division, State, and County
Location
Data are available for the United States by Region, Division, State, County. Select the location(s) for the query. Any number of locations can be specified here.
How?Hints:
- Click a round button to switch between the State and County list or the Region and Division list.
- See "How do I use a Finder?" for more information.
- See Finder Tool help for more hints.
- The default is all values (the United States).
- The Advanced mode let you easily pick several items from different parts of the list. Items are not selected until you click the "Move" button in Advanced mode. You may also enter values by hand, one code per line, in the Advanced mode. Use the Finder to see the correct code format. For example, 05 is the Arkansas state code.
- The "plus" symbol, "+" indicates that you can open the item, to see more items below it.
- The results to a search are shown in blue, and indicated by ">".
Region
Regions are multi-state groups. For regional data, you can group by Region, or you can select any combination of individual regions.How?Notes:
- See Location above for instructions.
- See also Group Results By in Step 1.
- The Regions are identified by both name and codes in data extracts.
- The United States is split into 4 regions: Northeast, Midwest, South and West. The states that comprise each region are shown below.
Division
Divisions are multi-state groups, sub-sets of Regions. For division-level data, you can group by Division, or select any combination of individual divisions.How?Notes:
- See Location above for instructions.
- See also Group Results By in Step 1.
- The divisions are identified by both name and codes in data extracts. To see all of the states in each division, group the data by Division and by State.
- The United States is split into 9 divisions by the Census Bureau:
- Division 1: New England, (CENS-D1)
- Division 2: Middle Atlantic, (CENS-D2)
- Division 3: East North Central, (CENS-D3)
- Division 4: West North Central, (CENS-D4)
- Division 5: South Atlantic, (CENS-D5)
- Division 6: East South Central, (CENS-D6)
- Division 7: West South Central, (CENS-D7)
- Division 8: Mountain, (CENS-D8)
- Division 9: Pacific, (CENS-D9)
The states that comprise each division are shown below.
State FIPS Code Division 1: New England, (CENS-D1) Connecticut 09 Maine 23 Massachusetts 25 New Hampshire 33 Rhode Island 44 Vermont 50 Division 2: Middle Atlantic, (CENS-D2) New Jersey 34 New York 36 Division 3: East North Central, (CENS-D3) Illinois 17 Indiana 18 Michigan 26 Ohio 39 Wisconsin 55 Division 4: West North Central, (CENS-D4) Iowa 19 Kansas 20 Minnesota 27 Missouri 29 Nebraska 31 North Dakota 38 South Dakota 46 Division 5: South Atlantic (CENS-D5) Delaware 10 District of Columbia 11 Florida 12 Georgia 13 Maryland 24 North Carolina 37 South Carolina 45 Virginia 51 West Virginia 54 Division 6: East South Central (CENS-D6) Alabama 01 Kentucky 21 Mississippi 28 Tennessee 47 Division 7: West South Central (CENS-D7) Arkansas 05 Louisiana 22 Oklahoma 40 Texas 48 Division 8: Mountain (CENS-D8) Arizona 04 Colorado 08 Idaho 16 Montana 30 Nevada 32 New Mexico 35 Utah 49 Wyoming 56 Division 9: Pacific (CENS-D9) (Alaska)* 02 California 06 (Hawaii)* 15 Oregon 41 Washington 53 * Alaska and Hawaii are not included in these data.
State
For state level data, you can select any combination of individual states. Or group by State and leave the Location Finder selection at the default (all locations or the 48 United States and the District of Columbia).How?Notes:
- See Location above for instructions.
- See also Group Results By in Step 1.
- The states and the District of Columbia are identified by both state name and Standard Federal Information Processing (FIPS) codes in data extracts. See About FIPS Codes below.
County
County-level data are available for the United States and the District of Columbia. For county level data, you can select any combination of individual counties, or group by County. Leave the Location Finder selection at the default (all locations or the 48 United States and the District of Columbia).How?Notes:
- See Location above for instructions.
- See also Group Results By in Step 1.
- The county coded represents the spatial average of data observations from 1 kilometer square spatial resolution grids. Grids are coded to the county that includes the grid centroid.
- The counties and the District of Columbia are identified by both county name and Standard Federal Information Processing (FIPS) codes in data extracts. The county locations are from the 1999-2000 Federal Information Processing (FIPS) code set.
- About FIPS Codes: The FIPS State and county codes were established by the National Bureau of Standards, U.S. Department of Commerce in 1968. This standard set of codes provides names and codes for counties and county equivalents of the 50 States of the United States and the District of Columbia. Counties are considered to be the "first order subdivisions" of each State, regardless of their local designation (county, parish, borough, census area). Washington, D.C.; the consolidated government of Columbus City, Georgia; the independent cities of the States of Maryland, Missouri, Nevada, and Virginia; and the census areas and boroughs of Alaska are identified as county equivalents. The system is standard throughout the Federal Government. The State codes are ascending, two-digit numbers; the county codes are ascending three-digit numbers. For both the State and county codes, space has been left for new States or counties. Some changes in the FIPS codes and county boundaries have occurred since 1968. See Location Updates for information on how these changes affect the data.
- About County Changes: Comparable measures may be misleading for counties with changing boundaries. See Location Updates for information on how these changes affect the data. Due to boundary changes, data are available for some counties for a limited period of time.
The following county-level constraints apply to the data:
- Alaska: data for Alaska are not included in this NLDAS average daily air temperature collection.
- Colorado:
- Broomfield county, Colorado (FIPS code 08014) - data are not available for this entity.
- Florida:
- Dade county, Florida (FIPS code 12025) - data are shown for the Dade county code value 12025, also the location of Miami, Florida.
- Hawaii: data for Hawaii are not included in this NLDAS average daily air temperature collection.
Step 3. Select year, month and day:Select the time period for the query. Any number of dates can be specified here. Individual date fields allow you to separately limit or filter data for Year (2003-2008), Month (January - December), and Day of Month (1-31) or Day of Year (1-366). The Aggregate Date Finder lets you select specific year/month/day dates, such as January 1, 2003.How?Hints for the Aggregate Date Finder:
- Click a round button to switch between Individual Date Fields or Aggregate Dates.
- See "How do I use a Finder?" for more information on using the Aggregate Date Finder.
- See Finder Tool help for more hints.
- The default for the Aggregate Date Finder is all values (2003/01/01 - 2008/12/31).
- The Advanced mode let you easily pick several items from different parts of the list. Items are not selected until you click the "Move" button in Advanced mode. You may also enter values by hand, one code per line, in the Advanced mode. The code format is YYYY/MM/DD. For example, 2003/09/01 is September 1, 2003.
- The "plus" symbol, "+" indicates that you can open the item, to see more items below it.
- The results to a search are shown in blue, and indicated by ">".
Year
Select All Years or any number of individual years (2003 - 2008).How?
- Click a round button to indicate Individual Date Fields.
- Click your left Mouse button on any desired single option in the list box.
- Press the Ctrl key while clicking your left Mouse button to make multiple selections.
- Press the Shift key while clicking your left Mouse button and dragging the selection for a range of values.
Month
Select All Months or any number of individual months (January - December).How?
- Click a round button to indicate Individual Date Fields.
- Click a round button to indicate Day of Month Fields.
- Click your left Mouse button on any desired single option in the list box.
- Press the Ctrl key while clicking your left Mouse button to make multiple selections.
- Press the Shift key while clicking your left Mouse button and dragging the selection for a range of values.
Day of Month
Select All Days or any number of individual days (1 - 31).How?Notes:
- Click a round button to indicate Individual Date Fields.
- Click a round button to indicate Day of Month Fields.
- Click your left Mouse button on any desired single option in the list box.
- Press the Ctrl key while clicking your left Mouse button to make multiple selections.
- Press the Shift key while clicking your left Mouse button and dragging the selection for a range of values.
Data are reported as "Missing" when the selections in the Individual Date Fields are not found in the data. For example, if data are limited to Day of Month values (29, 30, 31) for All Years in the month of February, then data are only reported for February 29 in year 2004 and year 2008. If the query also shows the data grouped by "Day of Month" and shows zero-value rows, then you see "Missing" in the cells for days 30 and 31.
Step 4. Select values:Limit your data to the selected average daily fine particulate matter (PM2.5) values (µg/m³). PM2.5 particles are air pollutants with an aerodynamic diameter less than 2.5 micrometers. The average daily values in the 2003-2008 data set range from 0 to >=65 (µg/m³).How? Press the Shift key while clicking your left Mouse button and dragging the selection for a range of values.
Fine Particulate Matter (µg/m³)
Limit your data to the selected fine particulate matter values. Select All Values or any combination of the individual values in the list box.
How? See "How do I select items from the list box?".Notes:
- Note that the values in the list box are the range of average daily values available in the data.
- Values are a spatial average of the daily fine particulate matter (PM2.5) values recorded for each 10 kilometer square spatial resolution grid, aggregated at the county level.
- PM2.5 particles are air pollutants with an aerodynamic diameter less than 2.5 micrometers. The average daily values in the 2003-2008 data set range from 0 to >=65 micrograms per cubic meter (µg/m³).
- About the upper threshold:
A threshold of 65 micrograms per cubic meter (µg/m³) was included as part of the Bspline model parameters. A threshold is needed since the Bspline is a fitting technique and not an interpolating technique. When fitting a sparse dataset, the fitted values can reach very high levels near the geographic boundaries. In this data set, values above a threshold of 65 (µg/m³) are truncated, or set to a maximum value of 65, because this value was the Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) for PM2.5 (98th percentile, averaged over 3 years) at the time this algorithm was developed.
Step 5. Other options:
Export Results If checked query results are exported to a local file. More information on how to import this file into other applications can be found here.
How? See "How do I use a checkbox?"Show Totals If checked totals and sub-totals will appear in the results table.
How? See "How do I use a checkbox?"Show Zero Values If checked, rows containing zero counts are included in the results table. If unchecked, zero count rows are not included.
How? See "How do I use a checkbox?"Precision Select the precision for rate calculations. When the rate calculated for a small numerator (incidence count) is zero, you may increase the precision to reveal the rate by showing more numbers to the right of the decimal point.
How? See "How do I select items from the list box?"Data Access Timeout This value specifies the maximum time to wait for the data access for a query to complete. If the data access takes too long to complete, a message will be displayed and you can increase the timeout or simplify your request. If you can't complete a request using the maximum timeout, contact user support and we will try to run a custom data request for you.
How? See "How do I select items from the list box?"
Data Source Information
Data Sources In a study funded by the NASA Applied Sciences Program / Public Health Program (fully cited below), scientists at NASA Marshall Space Flight Center / Universities Space Research Association modified the regional surfacing algorithm of Al-Hamdan et al. (2009) and used it to generate continuous spatial surfaces (grids) of daily PM2.5 for the whole conterminous U.S. for 2003-2008. Two sources of environmental data were used as input to the surfacing algorithm, US EPA AQS PM2.5 in-situ data and NASA MODIS aerosol optical depth remotely sensed data. They also identified in a Geographic Information System (GIS) the associated geographic locations of the centroids of the gridded PM2.5 dataset in terms of the counties and states they fall into to enable aggregation to different geographic levels in CDC WONDER See also Data Source Information.
To learn more about the methods and source of these data, please reference:
- NASA MODIS Atmosphere web site
- EPA AQS web site
- Al-Hamdan et al. (2009) PM2.5 Surfacing algorithm
- See also Data Source Citations
Additional Information
Suggested Data Source Citations Daily Fine Particulate Matter (PM2.5) (µg/m³) for years 2003-2008 on CDC WONDER Online Database, released 2012.
The suggested citation including the original series for the data is shown below each table, chart or map.
Contact For data questions that are not addressed in this document, e-mail mohammad.alhamdan@nasa.gov or bill.crosson@nasa.gov Acknowledgements This work was part of a collaborative study funded by the NASA Applied Sciences Program/Public Health Program (grant# NNX09AV81G), whose team members are:
- Dr. Leslie McClure (PI), School of Public Health, University of Alabama at Birmingham
- Dr. Mohammad Al-Hamdan (Co-PI), Universities Space Research Association, NASA Marshall Space Flight Center
- Dr. William Crosson (Co-I), Universities Space Research Association, NASA Marshall Space Flight Center
- Ms. Sigrid Economou (Collaborator), Centers for Disease Control and Prevention
- Mr. Maurice Estes, Jr. (Co-I), Universities Space Research Association, NASA Marshall Space Flight Center
- Ms. Sue Estes (Co-I), Universities Space Research Association, NASA Marshall Space Flight Center
- Mr. Mark Puckett (Collaborator), Centers for Disease Control and Prevention
- Dr. Dale Quattrochi, Jr. (Co-I), Earth Science Office, NASA Marshall Space Flight Center
Other Topics: Reference the following topics:
Locations: About County Level Changes
Contact for Data Questions
Suggested Citation
Location Updates: notes about specific county-level changes in boundaries and codes
Comparable measures may be misleading for counties with changing boundaries. The data collection may lag behind some Federal Information Processing (FIPS) location code changes. Some places, such as independent cities and New York City boroughs are included as unique locations in the data. Some county and census tract area (CA) locations are not included, instead the data are associated with a neighboring county or the previous location name and FIPS code. The list below of county-level changes is organized alphabetically by state name and then county name.
- Alaska boroughs and census areas:
Data are not available for the state of Alaska, nor Alaskan boroughs and census areas.- Colorado: Broomfield county
Broomfield county, Colorado (FIPS code 08014) was created effective November 15, 2001 from parts of four counties: Adams, Boulder, Jefferson, and Weld. Data are not available for Broomfield county. Data are aggregated within the previous boundaries of adjacent Adams, Boulder, Jefferson, and Weld counties.- Florida: Dade county and Miami city
Dade county, Florida (FIPS code 12025) was renamed Miami-Dade County and its FIPS code changed to 12086, effective November 13, 1997. The previous label and code, Dade county (FIPS code 12025), are used here.- Maryland: Baltimore city and Baltimore county
The independent city of Baltimore, Maryland has been treated as a county. Data are reported separately for Baltimore city (FIPS code 24510) and Baltimore county (FIPS code 24005).- Missouri:
- St. Genevieve county, Missouri
In order to achieve alphabetical consistency, the FIPS code for St. Genevieve, Missouri was changed in 1979 from 29193 to 29186. The new code (29186) is used here.- St. Louis city and St. Louis county, Missouri
The independent city of St. Louis, Missouri has been treated as a county. Data are reported separately for St. Louis city (FIPS code 29510) and St. Louis county (FIPS code 29189).- Nevada: Carson City
The independent city of Carson City, Nevada (FIPS code 32510) has been treated as a county. Data are shown separately from the adjacent counties for Carson City, Nevada.- New York: New York City boroughs
The five boroughs of New York City have been treated as counties and maintained as separate entities.
Borough County FIPS Code Bronx Bronx 36005 Brooklyn Kings 36047 Manhattan New York 36061 Queens Queens 36081 Staten Island Richmond 36085
- Virginia independent cities:
- Alleghany, Virginia
Alleghany, Virginia (FIPS code 51005) and Clifton Forge city, Virginia (FIPS code 51560) are reported separately.- Clifton Forge city, Virginia
On July 1, 2001, Clifton Forge city, Virginia (FIPS code 51560), formerly an independent city, merged with Alleghany county (FIPS code 51005). However, data for Clifton Forge city are reported separately from Alleghany county, Virginia (FIPS code 51005) for all years.- Nansemond city, Virginia
Nansemond city, Virginia (FIPS code 51123) has been part of the independent city of Suffolk, VA (FIPS code 51800) since 1979. For all years, data for Nansemond are aggregated and reported with those for Suffolk city.- Table of Virginia independent cities and counties
The Virginia independent cities are treated as counties and appear on the data with the following FIPS codes:
