Hazardous Air Pollutants Ambient Air Monitoring Data Review

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Hazardous Air Pollutants Ambient Air Monitoring
Data Review

• Air Toxics What We Know, What We Dont Know, and
  What We Need to Know
•    October 17-18, 2005 University of Houston
  Hilton Houston, Texas

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Houston Regional Monitoring Network

• Houston Regional Monitoring (HRM)
• A voluntary industry consortium
• Operates an ambient air quality-monitoring
  network in the Houston ship channel area
• Continuous criteria pollutant data collected for
  past 24 years,
• Periodic (24 hour composite samples, every 6th
  day) VOC data collected for past 18 years
• Data gathered and reported to date are effective
  in assessing long-term trends for specific
  pollutants

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Houston Area Air Monitors

• Houston ranks 1 in the number of air monitors in
  the nation
• There are 48 ozone monitors in the
  Houston-Galveston-Brazoria (HGB) area operated by
  the TCEQ, City, Harris County, HRM, and other
  independent sources
• There are 32 monitors that measure hazardous air
  pollutants (HAPs) in HGB

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Sampling and Analytical Methodology

• HRM routinely samples for 157 VOCs at seven sites
  in Houston Ship Channel
• 24-hour time averaged canister VOC samples are
  collected once every 6th day
• Samples are analyzed by EPA TO-15
• Samples are analyzed by gas chromatography/mass
  spectroscopy
• To date over 9,000 samples have been collected
  and reported

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HGB HAP Monitors
Legend TCEQ EISM sites HRM sites
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Benzene marginally exceeds the annual ESL at a
single site in the HRM Network
ESL Based on Odor
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How does Houstons air compare to that of other
cities for selected compounds?
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How Are 1,3-Butadiene Levels Trending in the
Houston Ship Channel?
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Annual Median 1,3-Butadiene Concentration at HRM
Sites
Annual Medians have declined below 1 ppb-V since
2002
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Annualized 1,3 Butadiene Reduction Trend Over
10-Year Period (1995-2004)
Annualized trend based on linear regression
model
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Comparison of HRM and TCEQ Annual Mean
1,3-Butadiene Concentrations in Houston Compared
to Trends from Other US Cities (1-01-01-03
through 12-31-03) EPA AIRData
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Observations and Conclusions

• Houston industry working in concert with the TCEQ
  has been active in collecting long-term (high
  quality) measurements to assess community
  exposure
• There are over 30 HAP monitors currently
  operating in the Greater Houston Metropolitan
  area making this area the most heavily monitored
  area for hazardous air pollutants in the US
• It is expected that emissions of HRVOC and
  associated HAPs will continue to decline in
  Houston as new rules are phased in to meet the
  8-hour Ozone standard
• Long-term measurements of air toxics are expected
  to continue in order to address questions with
  regard to community health
• HRM will continue to do its part to provide high
  quality data to better understand air quality
  issues in the region
• Houstons air quality has dramatically improved
  and will continue to improve

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