Smog Alerts (Stage 1)

OZONE, 1976-2010

Number of Basin-Days Exceeding Health Standard Levelsa)

Year

Old Federal Standard*

(1-hour average

> 0.12 ppm)

1997 Federal Standard*

(8-hour average

 > 0.08 ppm)

2008 Federal Standard*

(8-hour average

 > 0.075 ppm

Health Advisory

(1-hour average

³ 0.15 ppm)

Stage 1 Episode

(1-hour average

³ 0.20 ppm)

Basin

Maximum

1-hour average
(ppm)

Basin Maximum 8-hour Average

(ppm)

1976

194

206

213

166

102

0.38

0.268

1977

208

223

232

184

121

0.39

0.284

1978

187

200

219

173

116

0.43

0.321

1979

191

204

234

169

120

0.45

0.312

1980

167

186

210

152

101

0.41

0.288

1981

180

198

227

159

99

0.37

0.266

1982

149

168

194

121

63

0.40

0.266

1983

152

169

191

138

84

0.39

0.245

1984

173

194

213

146

97

0.34

0.249

1985

158

188

210

136

83

0.39

0.288

1986

164

194

220

140

79

0.35

0.251

1987

160

182

200

130

66

0.33

0.210

1988

178

197

217

144

77

0.35

0.258

1989

157

186

220

120

54

0.34

0.253

1990

130

163

191

107

41

0.33

0.194

1991

130

162

186

100

47

0.32

0.204

1992

143

176

201

109

41

0.30

0.219

1993

124

170

193

92

24

0.28

0.195

1994

118

152

174

96

23

0.30

0.209

1995

98

122

151

59

14

0.26

0.204

1996

90

127

154

53

7

0.24

0.175

1997

68

138

174

28

1

0.21

0.165

1998

62

119

147

43

12

0.24

0.206

1999

41

120

152

12

0

0.17

0.143

2000

40

106

137

17

0

0.184

0.159

2001

36

93

132

15

0

0.190

0.146

2002

49

99

135

18

0

0.167

0.148

2003

68

120

141

36

1

0.216

0.200

2004

28

90

126

4

0

0.163

0.148

2005

30

84

117

11

0

0.182

0.145

2006

35

86

116

9

0

0.175

0.142

2007

18

79

108

6

0

0.171

0.137

2008

28

80

120

9

0

0.176

0.131

2009

15

81

113

6

0

0.176

0.128

2010

7

68

109

0

0

0.143

0.123

ppm = parts per million parts of air, by volume.
*  The federal 8-hour ozone standard was revised from 0.08 ppm to 0.075 ppm, effective May 27, 2008.
a) Basin-days represents the number of days a standard was exceeded anywhere in the South Coast Air Basin.

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