PAMS Photochemical Assessment Monitoring Station TOXICS DATA ANALYSIS with a focus on transport June

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PAMS (Photochemical Assessment Monitoring
Station) TOXICS DATA ANALYSIS with a focus on
transportJune 14, 2005 MATI Meeting

• Tom Downs
• Chief Meteorologist
• Maine DEP Bureau of Air Quality
• tom.downs_at_maine.gov

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TYPE I -upwind / background site TYPE 2 max
emissions site TYPE 3 - maximum ozone site TYPE
4 - extreme downwind site
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PERIOD OF DATA

• PAMS SEASON ONLY June 1 to August 31
• 1997-2004 TOP OF CADILLAC
• 1994-2004 CAPE ELIZABETH
• 1995-2003 NEWBURY, MA
• 1994-2003 LYNN, MA

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Of 54 VOC compounds monitored at PAMS sites,
what is the relative ranking of toxics (primarily
mobile source) compounds by weight (ppbc)?
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1994-2004 AVERAGE CONCENTRATION TRENDS--WITHOUT
METEOROLOGY FACTORED IN
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MAAG
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DOES THE DIURNAL TREND INDICATE TRANSPORT?
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TRANSPORT SIGNAL (peak later in the day than
sites to the south)
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Is there a noticeable concentration gradient?
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Where do the highest Concentrations of Benzene
and Toluene come from?
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An indication of transport is the relative age
of the air mass.Benzene/Toluene ratio or any
other less reactive/more reactive compound ratio
can give you an indication of the relative age of
the air reaching a monitoring site
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CONCLUSION

• Only Benzene had concentrations anywhere near the
  Maine Ambient Air guidelines
• Local and long range transport are factors
  contributing to benzene concentrations at
  Cadillac and Cape Elizabeth