U.S. Environmental Protection Agency - Region 9

FACT SHEET

FINAL FINDING OF ATTAINMENT FOR
THE PHOENIX METROPOLITAN
OZONE NONATTAINMENT AREA

May 15, 2001

Today's Action

! We are finalizing our finding that the Phoenix metropolitan area has met the health-based
1-hour air quality standard for ground-level ozone (smog) as required by the Clean Air
Act.

! We are also suspending several air quality planning requirements in the Phoenix area that
are unnecessary for areas meeting the 1-hour ozone standard. These include: 1) the
requirement to reduce emissions of ozone precursors by at least 3 percent per year from
1997 through 1999; 2) a demonstration that the 1-hour ozone standard would be met by
November 15, 1999; and 3) adopted contingency measures that would be implemented if
the area did not attain or meet the required rate of emission reductions.

! We are not redesignating the Phoenix area to attainment. Before we can formally

redesignate the area to attainment, the State needs to develop an air quality maintenance
plan that demonstrates the Phoenix area will maintain the 1-hour ozone standard for 10
years. We will work with the State of Arizona and local air quality agencies towards
developing the maintenance plan so the area can be redesignated to attainment as soon as
possible.

Phoenix's Air Quality

! Our finding is based on air monitoring data collected in the Phoenix area from 1997

through 1999. During this three-year period, the Phoenix area did not experience a single
day with ozone levels above the 1-hour ozone standard. The 1-hour ozone standard is
0.12 parts per million (ppm) not to be exceeded more than an average of one day per year
over a three-year period.

! The clean record continued in 2000.


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! The clean air is the direct result of Arizona's commitment to adopt controls that reduce
ozone levels. The key controls adopted by Arizona to improve air quality in the Phoenix
area include cleaner burning gasoline, Arizona's premier vehicle emissions inspection
program, and numerous pollution reduction measures for industrial and commercial
sources. Arizona will need to continue to implement these controls in order to maintain
clean air.

! In 1997, EPA established a revised ozone standard of 0.08 ppm averaged over an 8 hour
period. While the Phoenix area is currently showing attainment of the 1-hour ozone
standard, it continues to violate the 8-hour standard and will need to take additional steps
in the future to ensure attainment of the 8-hour ozone standard.

Background: Ozone's Impact on Public Health

! Exposure to ambient ozone concentrations, even at relatively low levels, can cause
respiratory symptoms such as a reduction in lung function, chest pain, and cough.
Repeated exposure can make people more susceptible to respiratory infection and lung
inflammation, and can aggravate pre-existing respiratory diseases.

! Children are most at risk from exposure to ozone because they are active outside, playing
and exercising, during the summertime when ozone levels are at their highest. The
elderly and those with respiratory diseases such as asthma are also at high risk.

! Long-term exposure to ozone can cause irreversible changes in lung structure, which can
lead to chronic respiratory illnesses such as emphysema, chronic bronchitis, and
premature aging of the lungs.

Further Information

! The published finding and additional information regarding this action can be found on
our website at: http://www.epa.gov/region09/air.

! For more information, please call Colleen McKaughan, Associate Director, Air Division,
U.S. EPA Region 9 at (520) 498-0118 or Doris Lo, Air Quality Planner, Air Division,
U.S. EPA Region 9 at (415) 744-1287.

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