The Heinz Center's State of the Nation's Ecosystems
ecosystem: Urban and Suburban Areas
indicator Name: Air Quality (High Ozone Levels)
page # in printed report: 188
location on page: Upper left
data source: U.S. Environmental Protection Agency. Coverage includes Alaska and Hawaii. Data from before 1990 exist, but they are not directly comparable. Only monitoring stations located in urban/suburban areas were included in the analysis.
notes: please see technical notes for further details on accessing these data from their original source; this data table comes from a specific graphic in The State of the Nation's Ecosystems report (www.heinzctr.org/ecosystems)

units: % of All Urban and Suburban Air Monitoring Stations
Year At Least 25 Days per Year At Least 10 Days per Year At Least 4 Days per Year At Least 1 Day per Year
1990 7.7 20.9 45.3 76.0
1991 9.7 33.1 53.2 76.9
1992 6.2 12.8 29.9 67.6
1993 5.6 18.4 36.3 70.6
1994 5.3 18.3 42.9 73.3
1995 7.1 29.7 60.4 78.6
1996 5.0 13.8 42.8 74.4
1997 3.1 15.2 41.6 69.3
1998 5.3 29.4 58.2 80.5
1999 3.7 28.7 57.3 79.8
2000 3.4 10.6 29.8 65.5
2001 3.4 12.1 35.6 68.1
2002 4.3 34.4 53.6 72.8
2003 4.1 8.3 28.7 66.6
2004 1.3 6.0 11.4 34.4

Close Window