Defining the Problem with HRVOC What we know

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Defining the Problem with HRVOC(What we know)

• October 6, 2003 HRVOC Work Group Meeting

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Typical Urban Area Ozone Exceedance
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Explosive rate of ozone increase at Capitol
Site 60 ppb/hr for 2 hours
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Most Abundant VOC Species Identified at BR
Capitol Site(Top 10 Represent 48 of Total VOC)
propane n-butane ethane isopentane
(2-methylbutane ) ethylene isobutane
(2-methylpropane) propylene n-pentane toluene n-he
xane
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VOC Species at BR Capitol SiteRanked by Ozone
Forming Potential(Top 10 Represent 95 of Total
Reactivity)
ethylene propylene isoprene m/p-xylene 1-butene n-
butane isopentane (2-methylbutane
) toluene o-xylene isobutane (2-methylpropane)
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Capitol Site Monitored Emissions
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Capitol Site Monitored Emissions
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Capitol Site 7.3 HRVOC Preceding Highest Ozone
Reading
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Bayou Plaquemine Site 19 HRVOC Preceding Highest
Ozone Reading
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VOC to NOx Ratios

• The ratio of VOC concentration to NOX
  concentration can provide information as to the
  effect on the ozone concentration of changes in
  precursor concentrations.
• If the VOC/NOX ratio is greater than
  approximately 6 9, the system is termed
  NOX-limited and decreases in NOX are expected to
  decrease ozone.
• If the VOC/NOX ratio is less than 6 - 9, the
  system is termed VOC limited and decreases in NOX
  are expected to increase the peak ozone
  concentration

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NOx Limited
VOC Limited
VOC/NOx lt4.0 Hydrocarbon Limited 8.0
Neutral gt12 Nox Limited
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Limited
NOx
VOC Limited