The document discusses various applications of air quality data including regulatory exceptions, hemispheric transport projects, and atmospheric composition portals. It also describes the Air Quality Community of Practice's contributions to the GEOSS Common Infrastructure through developing an air quality community catalog and data finder to help users discover and access air quality data and metadata registered in the GEOSS clearinghouse and registry.

1. Air quality: Many Observations, Many Applications

2. AQ Regulatory Application: Exceptional Events

3. Hemispheric Transport Application: HTAP Project

4. Atmospheric Composition Portal: ACC Project

5. 2009 AQ CoP and the GEOSS Infrastructure Users GEOSS Common Infrastructure Air Quality Community Catalog SEDAC DataFed Giovanni EDAC NGC ESA 100+ data web service metadata registrations AIP-2 Workspace: https://sites.google.com/site/geosspilot2/air-quality-and-health-working-group AQ Community Data Finder AQ User Apps GEO Portsals AQ CoP Contributions to GEOSS GCI through AIP II: Air quality Community Catalog Developed Discovery Metadata for Air Quality AQ Community Data Finder GEOSS Clearinghouse GEOSS Registry

6. Example use of the GEOSS Common Infrastructure GUI Finder of AQ Data in the GEOSS Clearinghouse GEOSS Common Infrastructure GEOSS Registry GEOSS Clearing-house Search for AQ data Return AQ metadata filtered AQ metadata available to other applications through RSS, atom, etc. http://webapps.datafed.net/AQ_uFIND.aspx