Evolution and Air Quality Benefits of
Arizona Cleaner Burning Gasoline
Essential Services Task Force
January 5, 2004
Ira Domsky
Deputy Director
Air Quality Division
Overview
Gasoline properties and automobile
emissions
History of CBG standards
Air quality benefits
Gasoline Properties and
Emissions
Pollutants of Concern




Carbon Monoxide
Hydrocarbons – evaporative and tailpipe
Oxides of Nitrogen
Hazardous Air Pollutants
 Benzene
 Butadiene
 Aldehydes
 Other products of incomplete combustion
Gasoline Properties and
Emissions
Gasoline Properties





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Octane or anti-knock index
Volatility
Distillation “curve”
Oxygen
Sulfur
Aromatic hydrocarbons
Olefins
Benzene
Gasoline Properties and
Emissions
Always regulated for driveability
(poor driveability results in high emissions)



Octane
Volatility
Distillation
Regulated specifically for emissions
control

All the rest
Evolution of CBG Standards
Common theme:

Many changes to gasoline standards
adopted in Maricopa County have been
driven by citizen lawsuits under the Clean
Air Act
Some changes were fostered by
enlightened self-interest:

Achieving attainment was good for
business as well as public health
Evolution of CBG Standards
Why gasoline standards are attractive
emission control strategies




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Emission reductions are relatively large
Automobiles account for the majority or a
plurality of pollution
No changes to engines or other technology
are necessary
Reduces emissions for all vehicle trips
Everyone who uses gasoline pays
Evolution of CBG Standards
Year
1988
1991
1992
1993
1993
1995
1996
1997
1998
2000
Change
Pollutants
CO
Oxygen content increased, new RVP standards
CO, HC
County-wide for oxygenated fuels
CO
Wintertime RVP reduction
CO
Oxygen content increased & RVP decreased again CO
Oxygenated fuels control period reduced
Gov. Symington opts-in to federal RFG program
HC/NOx
Arizona CBG standards adopted
HC/NOx
Wintertime CARB 2 adopted; Area A expanded
CO
Summertime minimum oxygen standard repealed Oxygenated fuels adopted in nonattainment area
Air Quality Benefits
Cumulative Improvements
Emissions
Reductions
(tons/day)
Percent of
Nonattainment
Area Emissions
Season
Pollutant
Winter
Carbon
Monoxide
44
6.8%
Hydrocarbons
29
8.9%
7
2.1%
Summer
Oxides of
Nitrogen
Air Quality Benefits
Carbon Monoxide Violations and Concentrations
Maricopa County, 1984 - 2002
180
140
Number of Violations
16
150
14
133
120
12
109
Standard
100
10
80
8
60
6
37
40
4
27
18
20
2
3
2
2
0
3
2
1
0
0
0
0
0
0
0
0
84
85
86
87
88
89
90
91
92
Violations
93
94
95
Second Hi
96
97
98
99
00
01
02
Concentration (ppm)
160
18
Air Quality Benefits
9
0.18
8
0.16
7
0.14
Standard
6
0.12
5
0.1
4
0.08
3
0.06
2
0.04
1
0.02
0
0
84
85
86
87
88
89
90
91
92
93
Violations
94
95
96
Second Hi
97
98
99
00
01
02
03
Concentration (ppm)
Number of Violations
1-Hour Average Ozone Violations and Concentrations
Maricopa County, 1984 - 2003
Air Quality Benefits
Visibility Trends
In the Phoenix Metropolitan Area, 1994 - 2002
100
87
Visual Range in Miles
80
64
64
49
53
39
40
68
58
55
60
64
32
31
29
31
20
18
18
18
18
1994
1995
34
33
35
19
19
21
19
2001
2002
32
20
0
1996
1997
1998
Dirtiest 20%
Average
1999
2000
Cleanest 20%