State Health Department Confirms Summertime Ozone Readings, Standard Violation
Nonattainment
Designation Expected From U.S. Environmental Protection Agency
September 20, 2007—Denver—The Colorado Department
of Public Health and Environment today confirmed that an
intensive review of ozone data collected by air quality
monitors through Aug. 31 this summer is complete and that a
violation of the federal health-based standard for ozone has
occurred at a Jefferson County monitor. “We’ve looked at
the numbers, the monitors and other related information, and
have concluded that the data are valid,” said Paul
Tourangeau, director of the Colorado Department of Public
Health and Environment’s Air Pollution Control Division. “We
will be transmitting the data to the EPA shortly and
anticipate that the Denver region will be formally
designated by the EPA as a ‘nonattainment’ area for ozone.”
Tourangeau continued: “The validation of the data is
important because it confirms our understanding of what the
status of the area will be in relationship to the federal
health-based standard. It compels us to move forward rapidly
to develop plans for further reductions in ozone
concentrations.”
A violation is not official until the EPA has reviewed all
relevant data and made a formal determination. The EPA is
expected to make its decision in November 2007. The
current federal health-based standard for ground-level ozone
is 0.08 parts per million (ppm) measured over eight hours.
The EPA determines compliance by reviewing three consecutive
years of data to arrive at an average that can be compared
to the standard. Data from each monitor are considered
separately. A violation at any one of the state’s 12
Denver-metropolitan area and North Front Range monitors
results in a nonattainment designation for the entire
region. Specifically, the fourth-highest reading each
calendar year is averaged with the fourth-highest readings
from the two previous calendar years for each monitor and
compared to the standard. Because of a rounding factor that
is included in the calculation, an average of 0.084 ppm or
lower is necessary to stay in compliance with the standard.
At the Rocky Flats area monitor, the three-year average
(2005-2007) currently is 0.085 ppm. All other monitors,
although periodically recording eight-hour concentrations at
or above the standard, remain in compliance based on their
three-year averages. In June, the U.S. Environmental
Protection Agency (EPA) proposed to lower the ground-level
ozone standard to a level ranging from 0.070 to 0.075 ppm
measured over eight hours, and the agency reports that it
will finalize a new federal standard next spring. However,
a nonattainment designation under
the existing standard is expected.
“The department anticipates that the EPA will designate a
nine-county region (Adams, Arapahoe, Boulder, Broomfield,
Denver, Douglas, Jefferson, Larimer and Weld counties) as
out of compliance with the existing eight-hour ozone
standard,” said Tourangeau. The department’s Air Pollution
Control Division, along with the Regional Air Quality
Council, the North Front Range Metropolitan Planning
Organization, other agencies in the region and stakeholders,
already has begun work to further reduce ozone
concentrations to attain the standard. A plan will be
submitted to the Colorado Air Quality Control Commission for
approval by the end of 2008, with legislative review
expected after that. Once all state approval processes have
been completed, the plan ultimately will be submitted by the
governor to the EPA for final approval. Ozone is an
important public health issue. Increased ground-level ozone
concentrations can compromise public health, especially
among sensitive populations like active children, the
elderly and those with pre-existing respiratory conditions
like asthma, at levels below the federal standard.
The Colorado Department of Public Health and Environment and
the Colorado Air Quality Control Commission have adopted
various emissions reduction strategies to achieve the
federal health-based ozone standards. --30-- |
