----------------- ---------- --------- ------------ ------------ ------------ ------------------ ----------- ---------- ---------- ---------- -----------------------------------------------------------------
  **SUMMARY OF                                                                                                                                  
  NETWORKS FOR                                                                                                                                  
  INORGANIC GASES**                                                                                                                             

  **Numbers of                                                                                                                                  
  Measurement Sites                                                                                                                             
  for Each                                                                                                                                      
  Inorganic Gas**                                                                                                                               

  **Network**       **Total    **Ozone   **Nitrogen   **Nitrogen   **Nitrogen   **Total            **Ammonia   **Nitric   **Sulfur   **Carbon   **Location of Information and/or Data**
                    Number of  (O3)**    Oxides       Oxide (NO)** Dioxide      ReactiveNitrogen   (NH3)**     Acid       Dioxide    Monoxide   
                    Sites**              (NOx)**                   (NO2)**      (NOy)**                        (HNO3)**   (SO2)**    (CO)**     

  **State / Local /                                                                                                                             
  Federal                                                                                                                                       
  Networks**                                                                                                                                    

  NCore^1,6^        75         75                     75           75           75                 75          75         75         75         <http://www.epa.gov/ttn/amtic/monstratdoc.html>

  SLAMS^2^          \~3000     1783      306          373          613          75                 29                     819        714        <http://www.epa.gov/ttn/airs/airsaqs/aqsweb/aqswebhome.htm>

  PAMS^2^           75         50        60           61           54           3                                                    1          <http://www.epa.gov/ttn/airs/airsaqs/aqsweb/aqswebhome.htm>

  CASTNet^3,7^      80+        88                                                                              88         88                    <http://www.epa.gov/castnet/>

  GPMP^2^           33         35                                                                                         4          1          <http://www2.nature.nps.gov/air/Monitoring/network.cfm#data>

  **Tribal                                                                                                                                      
  Monitoring                                                                                                                                    
  Networks**                                                                                                                                    

  Tribal^2^         120+       21        6            10           13           4                  1                      16         6          <http://www.epa.gov/ttn/airs/airsaqs/aqsweb/aqswebhome.htm>

  **Industry                                                                                                                                    
  Networks**                                                                                                                                    

  New Source        variable   8         18           20           24                                                     66         8          Contact specific industrial facilities
  Permit^2^                                                                                                                                     

  ARIES/SEARCH^4^   8          8         8            8            8            8                  2           8          8          8          <http://www.atmospheric-research.com/studies/SEARCH/index.html>

  HRM Network^5^    9          9                                   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\. Counts of sites for which selected inorganic gases are measured 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:

a\. SLAMS network includes: NAMS, SLAMS, other, non-regulatory, special
purpose, and unknown monitoring types

b\. PAMS network includes: PAMS and unofficial PAMS monitoring types

c\. GPMP network includes: Non-EPA federal monitoring type

d\. 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.

e\. New Source Permit network includes: Industrial type.

3\. Counts of sites for which selected inorganic gases are measured are
based on a \"Quick Report\" for 2004 from the CASTNet website made on
04/19/06; measurements of pollutants, other than O3, are based on Filter
Pack providing weekly integrated averages.

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

6\. Monitoring for NO2, NH3 and HNO3 under NCore is pending the
availability of suitable methods.

7\. HNO3 values under CASTNet include some volatile fraction from
particle nitrates.