The second release of collection 3 OMI/Aura Level-2 NO2 data product OMNO2 is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omno2_v003.shtml ) to public and science community from the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC).
      
      The Nitrogen Dioxide Product 'OMNO2' contains slant column NO2 (total amount along the optical path from the sun into the atmosphere, and then toward the satellite), the total vertical column NO2, the estimated tropospheric contribution to the total NO2 column, NO2 column hidden by any clouds in the OMI field of view, and other ancillary data.
      
      Nitrogen dioxide is an important chemical species in both the stratosphere, where it plays a key role in ozone chemistry, and in the troposphere, where it is a precursor to ozone production. In the troposphere, it is produced in various combustion processes and in lightning and is an indicator of poor air quality.
      
      (The shortname for this Level-2 OMI total column NO2 product is OMNO2) 
	    
	    The algorithm leads for this product are NASA OMI scientist Dr. Nickolay A. Krotkov and KNMI Scientist Dr.Pepijn J. Veefkind. 
      
      OMNO2 files are stored in EOS Hierarchical Data Format (HDF-EOS5). Each file contains data from the day lit portion of an orbit (~53 minutes). There are approximately 14 orbits per day. The maximum file size for the OMNO2 data product is about 15 Mbytes.
                  
      Data Category &Parameters:
      
      The OMNO2 data file contains one swath which consists of two groups:
      
      Data fields:
      Slant Column NO2 (total amount along the optical path from the sun into the 
      atmosphere and then toward the satellite), The Total Vertical Column NO2, and 
      the Estimated Tropospheric Contribution to the Total Column NO2, and Other 
      Ancillary Data including Data Quality Flags, Measures of Precision, Quality 
      Assurance (QA) information.
      
      Geolocation Fields:
      Latitude, Longitude, Time, Relative Azimuth, Solar Zenith andAzimuth,       
      Viewing Zenith and Azimuth angles, Spacecraft Altitude, Latitude, 
      Longitude, Terrain Height, Ground Pixel Quality Flags.