----------------- ---------- ---------- ----------------- ---------- -----------------------------------------------------------------
  **SUMMARY OF                                                         
  NETWORKS FOR                                                         
  PARTICULATE                                                          
  MATTER (PM)**                                                        

  **Numbers of                                                         
  Measurement Sites                                                    
  for Each                                                             
  Measurement of                                                       
  PM**                                                                 

  **Network**       **Total    **PM2.5    **PM2.5           **PM10**   **Location of Information and/or Data**
                    Number of  filter**   continuous^2^**              
                    Sites**                                            

  **State / Local /                                                    
  Federal                                                              
  Networks**                                                           

  NCore^1^          75         75         75                           N/A

  SLAMS^1,3^        \~3000     1573       647               1592       <http://www.epa.gov/ttn/airs/airsaqs/aqsweb/aqswebhome.htm>

  STN^3^            54         54                                      <http://www.epa.gov/ttn/airs/airsaqs/aqsweb/aqswebhome.htm>

  IMPROVE           110 plus   167                                     <http://vista.cira.colostate.edu/improve/>
                    67                                                 
                    protocol                                           
                    sites                                              

  **Tribal                                                             
  Monitoring                                                           
  Networks**                                                           

  Tribal^3^         120+       51         12                41         <http://www.epa.gov/ttn/airs/airsaqs/aqsweb/aqswebhome.htm>

  **Industry                                                           
  Networks**                                                           

  New Source        variable   1          1                 120        Contact specific industrial facilities
  Permit^3^                                                            

  ARIES/SEARCH^4^   8          8          8                 8          <http://www.atmospheric-research.com/studies/SEARCH/index.html>

  HRM Network^5^    9          9                            9          <http://hrm.radian.com/houston/how/index.htm>
  ----------------- ---------- ---------- ----------------- ---------- -----------------------------------------------------------------

Footnotes:

1.  NCore is a network proposed to replace NAMS, as a component of
SLAMS; NAMS are designated as national trends sites.

2\. Several methods are included (TEOM, light scattering, BAMS)

3\. Counts of sites for PM are based on a search of air quality
measurements in AQS that was made on 04/19/06. Monitor type, pollutant
or \"parameter\" code, and the last sampling date for a given monitoring
site were the primary search factors considered. Last sampling dates
encompassed 2004 to the present. Parameter codes unique to each
pollutant were chosen. The following monitor types were selected for
inclusion with the indicated types of networks:

SLAMS network includes: NAMS, SLAMS, other, non-regulatory, special
purpose, unknown, SLAMS speciation monitoring types

STN network includes: Trends speciation types

Tribal network includes: Tribal monitors type. Also, the number of sites
indicated for tribal monitoring is actually the number of monitors,
rather than sites. The number of sites with multiple monitors is
probably less than 80.

New Source Permit network includes: Industrial type.

4\. Counts of sites for which selected inorganic gases are measured are
based on information from SEARCH website taken 04/19/06.

5\. Counts of sites for which selected inorganic gases are measured are
based on information from the HRM website taken on 04/19/06.