P.O. Box 669, Billings, MT 59103-0669    e-mail: bhcc@msubillings.edu

  

   
   

Air Quality: Particulate Averages (UG/M3)
  

   
YEAR DOWNTOWN
1991 23
1992 27
1993 27
1994 28
1995 21
1996 21
1997 18.5
1998* 26
1999* 22
2000* 19
*Lockwood Park

Trend:   UNCLEAR


Source:
  Yellowstone County Air Pollution Control 406-256-6841

Caveats and Definitions
Particulate matter is defined as any material, except water in uncombined form, that is or has been airborne, and exists as a liquid or a solid at standard conditions. In late 1997, the downtown particulate monitor was moved to Lockwood Park.