September 20, 2005: Summary files have been generated from the EPA's national emissions inventory (NEI) database for criteria air pollutants for the years 1990 and 1996 through 2001. The files are in ASCII text format and have been compressed. Each year includes data files and a readme file that explains the file structure.

January 20, 2016:  Summary files have been added from 2002 and 2005 NEI for both criteria and hazardous air pollutants.  The files are in both Excel and Access format and have been compressed.

For years prior to 1990 and for the years 1991 through 1995, the NEI database contains trend level data.  This data is available in the annual air pollutant emissions trends report for 1970 through 2014.

Emissions Summary files:

• 1990
• 1996
• 1997
• 1998
• 1999
• 2000
• 2001
• 2002
• 2005