by Annette Prosterman, AACOG Natural Resources / Transportation Coordinator
July 15 marked the midway point
in the Ozone Season; that time of year stretching from April through September
when the area’s most prevalent form of air pollution, ozone, tends to
spike. At the midway milestone, the San Antonio-New Braunfels Metropolitan
Statistical Area (MSA) is in compliance with federal standards. This,
however, is a tenuous status, first because the season is only half over and
second because those standards are about to change.
“According to the current
standards of the Environmental Protection Agency set in 2008,” explains Brenda
Williams, Interim Director of Natural Resources at the Alamo Area Council of
Governments (AACOG), “our status is based on a three year average of the fourth
highest eight-hour daily ozone reading per year at the areas three regulatory
monitors. To remain within the federal standards, that three year average
at each monitor must be lower than 76 parts per billion.”
Table 1 below lists (as of July 15th) the fourth highest
daily maximum eight-hour ozone concentrations measured at the area's three
regulatory monitoring sites during the 2015 Ozone Season, along with the dates
in which those measurements were read:
Table 1: Highest
readings of 2015 at Regulatory Monitor Sites (as of 07-15-15)
|
Regulatory
Monitoring Site
|
Highest Reading
|
ppb
|
2nd Highest
|
ppb
|
3rd Highest
|
ppb
|
4th Highest
|
ppb
|
|
San Antonio NW C23
|
05/02
|
77
|
05/01
|
74
|
04/30
|
67
|
06/01
|
66
|
|
Camp Bullis C58
|
05/01
|
78
|
05/02
|
75
|
06/01
|
72
|
04/30
|
67
|
|
Calaveras Lake C59
|
05/01
|
68
|
05/02
|
66
|
04/30
|
63
|
04/27
|
60
|
While the readings listed in
Table 1 are yet to be confirmed by the Texas Commission on Environmental
Quality (TCEQ), the table shows that (as of 07/15/15) the fourth highest,
eight-hour average reading at the three regulatory monitors in the region,
San Antonio Northwest, Camp Bullis, and Calaveras Lake, were 66
ppb, 67 ppb, and 60 ppb, respectively. When those fourth
highest readings are averaged with the fourth highest readings from 2013 and
2014, as demonstrated in Table 2, below, the three year averages were 70
ppb at San Antonio Northwest, 74 ppb at Camp Bullis, and 64 ppb at
Calaveras Lake.
Table 2: 4th Highest
Readings and Average over 3 Years (as of 07-15-15)
|
Regulatory Monitoring Site
|
2013
|
2014
|
2015
|
Current 3-Year
Ave.
|
|
San Antonio Northwest C23
|
76
|
69
|
66
|
70
|
|
Camp Bullis C58
|
83
|
72
|
67
|
74
|
|
Calaveras Lake C59
|
69
|
63
|
60
|
64
|
If the current ozone season were
now over, the three-year average at none of the regulatory monitors would be
exceeding the standard of 75 ppb for ground level ozone. That’s good news,
because unlike the ozone in the Earth’s upper atmosphere that protects us from
the sun’s ultraviolet rays, ozone at ground level is a health hazard that can
cause respiratory irritation and pain, trigger or even cause asthma, and reduce
lung capacity and function. As Ms. Williams points out, however, “several
months still remain in the ozone season, with the worst peaks in ozone
typically occurring in September. It will be a challenge to remain in
compliance with the current standards through the end of the season.”
In addition, the EPA has stated
that it will lower the acceptable threshold for ozone to
somewhere between 65 and 70 ppb later in this
year, in the interests of better protecting public health and the environment.[1]
It is expected that next year’s attainment status for the MSA (which would be
an average of the fourth highest eight hour average readings of 2014, 2015, and
2016), will be based on that new standard.
Failure to meet air quality
standards will likely result in steps that local governments would be required
to implement in order to reduce pollution and regain our clean air status. For
example, new or expanding manufacturers may be required to secure pollution
reductions to offset their proposed growth, and transportation planners may be
required to prove that adding capacity to the roadway system would not increase
pollution from cars and trucks to qualify for federal highway funds for roadway
improvements.
Ground-level ozone forms in
intense sunlight when nitrogen oxides (such as those found in gasoline exhaust
and other emissions from fossil fuel combustion), combine with volatile organic
compounds (such as those found in gasoline vapors and solvent fumes). It builds
up in the air we breathe when winds are light or the air is still.
The City of San Antonio, the
Alamo Area Metropolitan Planning Organization, and other area governmental
entities represented on AACOG’s Air Improvement Resources (AIR) Committee are
teaming up to make reductions in ground-level ozone. “Keeping our levels of air
pollution down is a challenge that requires a shared commitment from regional
agencies and businesses, as well as individuals,” Ms. Williams comments.
