Baton Rouge VOC, NOx, Ozone Data Analysis Overview

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Baton Rouge VOC, NOx, OzoneData Analysis
Overview

• October 22, 2003
• Mark Sather, U.S. EPA Region 6, Air Quality
  Analysis Section
• E-mail sather.mark_at_epa.gov
• Phone [phone]

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• In both Baton Rouge and Houston significant
  decreases in ambient VOC concentrations and O3
  concentrations occurred between the late 1980s
  and early 1990s
• Ambient NOx concentrations have not significantly
  declined from 1985-2002

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• Both Stationary Sources and Mobile Sources are
  major contributors to ambient VOC and NOx
  concentrations in Baton Rouge as seen by sector
  analysis.
• NW sector higher VOC SE sector higher NOx

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Recent Speciated VOC Trends in Baton Rouge and
Houston

• For ethylene, propylene, and 1-butene, all
  important HRVOC, concentrations at the Baton
  Rouge Capitol site have recently risen to
  concentrations recorded at the Houston Clinton
  Drive site.
• Ethane, toluene, and benzene concentrations
  similar between the two sites.
• Both sites show recent decreases in
  concentrations for m/p xylene and m-ethyltoluene.

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Baton Rouge 1-hour Ozone Exceedance Days Breakdown

• From 1995-2003 about 25 of 1-hour ozone
  exceedance days exhibit a rapid rise of ozone
  during the exceedance hour.
• This is a similar percentage to what has been
  seen historically in Lake Charles, Longview,
  Beaumont
• El Paso40, Houston50, DFW0

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Summary

• Baton Rouge experienced its greatest decline in
  ozone concentrations from the late 1980s to the
  early 1990s, concurrent with major decrease in
  ambient VOC concentrations.
• From 1995-2003 about 25 of 1-hour ozone
  exceedances exhibited rapid rise (gt40 ppb) of
  ozone just before the exceedance hour 2 rapid
  rise days apiece in 2002 and 2003.
• Overall VOC concentrations have not decreased
  from the mid 1990s to 2002, and NOx
  concentrations have been steady from 1985-2002.
• Overall VOC concentrations at the Capitol site
  are a little lower than the similarly located
  Clinton Drive site in Houston, but some HRVOC
  like ethylene and propylene have recently risen
  at the Capitol site to concentrations seen in
  Houston.
• The Capitol site is a very good site to measure
  peak VOC/NOx from both stationary and mobile
  sources in central and north Baton Rouge future
  PAMS rule changes will result in more
  measurements being taken at the Capitol site.
• Other 2 PAMS sites mainly measure north and south
  boundary conditions for Baton Rouge area if
  additional precursor monitoring is undertaken in
  the future, areas for consideration could be in
  Ascension and Iberville parishes close to the
  significant cluster of stationary sources.