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Ozone Report
2008 8-hr. av. O3 National Ambient Air Quality Standard: The annual fourth-highest daily
maximum 8-hour concentration, averaged over 3 years, measured at each monitor within an
area must not exceed 0.075 ppm.1
2014 Compliance* with 2008 Eight-Hour Ozone Standard, SA Region2
Fourth Highest
Current*
4th Highest value
Monitoring Site
3-Year
in 2014 must fall
2012 2013 2014*
Average
below this value†
Camp Bullis C58
87
83
65
78
57
Calaveras Lake C59
70
69
63
67
88
San Antonio Northwest C23
81
76
60
72
70
* 2014 as of 11:12 am CST 7/13/2014; no new 2014 fourth-highest since AIR Tech of 6/9/14
† If the three year average for 2012-2014 is to be in compliance with the 2008 standard, the 4th
highest eight-hour average daily reading for 2014 must be less than these values.
On March 13, 2014, the regulatory monitoring station at Camp Bullis recorded an 8-hour average ozone
level of 59 ppb. Combined with the appropriate fourth-highest values recorded during 2012 and 2013, if
these readings are confirmed by TCEQ, then the San Antonio region will be have exceeded or violated
the current 2008 8-hour average ozone standard for the third year in a row.
During the June 9th meeting of the AIR Technical Committee, Vice-Chairman Nick Page asked if the Air
Quality Health Alerts in the AACOG region at the end of May provided eight-hour averages above 65 ppb
at Camp Bullis. A review of data including the Daily Maximum Eight-Hour Ozone Averages page showed
the Daily Maximum Eight-Hour Ozone Averages in TCEQ Region 13 for the last few days of May:
29 30 31
48
52
63
63
47
50
59
50
64
66
56
1
2
64
35
81
63
51
53
58
54
63
91
76
59
59
68
66
50
53
54
51
55
71
63
Monitoring Site
San Antonio Northwest C23
Camp Bullis C58
Calaveras Lake C59
Elm Creek Elementary C501
Fair Oaks Ranch C502
Bulverde Elementary C503
New Braunfels Airport C504
City of Garden Ridge C505
Seguin Outdoor Learning Center C506
Heritage Middle School C622
CPS Pecan Valley C678
http://www.epa.gov/air/criteria.html
http://www.tceq.state.tx.us/cgi-bin/compliance/monops/8hr_attainment.pl
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Because these high values are in traditionally upwind sites which have usually have lower ozone values,
they didn’t do anything to move the needle on the controlling monitor, C58, nor on the design value for
C59. But the striking difference of 56 ppb between the controlling monitor C58 and C622 made me think
again. A plot of the locations of the monitors using the AQI Index-related colors for the sites revealed an
unusual distribution pattern of higher readings.
Looking at the distribution, it is reasonable to imagine a gradient of concentrations ranging between 6075 ppb that would form a yellow band connecting C501 to C23 to C506 and which, like an isopleth,
would separate the higher values shown in orange to the south and east from the lower values shown in
white to the north.
Bryan Lambeth, meteorologist with TCEQ explained that the low ozone reading at Camp Bullis C58 on
May 30 was caused by an instrument problem. The data pulled had not yet been validated and
subsequently after validation some of the data that day was invalidated because of the instrument
problem and resulted in the peak 8-hour ozone being incomplete.
He provided plots using EPA’s AirNowTech Navigator web page, one of which is included below. He
explained that Navigator also produces HYSPLIT backward-in-time air parcel trajectories, so he ran a set
of three trajectories, each for a different altitude, to track the path of the air arriving near the time of the
ozone peak at Heritage Middle School. He also added output from the NOAA ozone model for
comparison each hour. He also added, “Please note that this is a very preliminary and limited analysis
and should not be used as an official assessment.”
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He explained, “Regional incoming ozone background levels were in the 50-60 ppb range as indicated by
sites on the north and northeast side of the San Antonio area that were primarily upwind that day. Winds
were very light and with sunny conditions and warm temperatures ideal for ozone formation and
accumulation. The NOAA ozone model performed fairly well on this day in showing the ozone peak on
the southeast side of the San Antonio area. Also, on the previous day we issued an Ozone Action Day
notice for this day.”
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