Aethalometer Work Update

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Aethalometer Work Update

• Traffic Analysis
• Wood Smoke Sites
• Univ of Washington Diesel Exposure Lab

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Objectives

• To introduce our network and project objectives
• To communicate analysis that has been
  accomplished by PSCAA
• Traffic Analysis
• Wood Smoke Sites
• Univ of Washington Diesel Exposure Lab
• To encourage other agencies to try continuous
  Black Carbon Technologies
• To acknowledge Aethalometer strengths and
  weaknesses to further understand instrument
  capabilities

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Aethalometer

• Magee Scientific Dual Channel Aethalometer
• BC Channel 880 nm
• UV Channel 370 nm
• Dr. Tony Hansen is the Principal Scientist
• PM 2.5 Head at 5 LPM

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Network Big Picture
Network Scope 110 Miles

• Almost Pure Wood Smoke Darrington Site
• Sep 2004
• Marysville Wood Smoke North Site
• Jan 2005
• Lake Forest Park Wood Smoke North Site
• Dec 2003
• Freeway Site
• Jan 2003
• Industrial Site
• Oct 2002
• Urban Background Site
• Jan 2003
• Wood Smoke South Site
• Dec 2003

Blue Sites denote Speciation Network
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Monitoring Strategy

• Olive Street Freeway Site
• 225,000 vehicles per day
• Mostly Light Duty Vehicles
• Seattle Duwamish Industrial Site
• 58,000 vehicles per day
• Port of Seattle Truck Arterial
• Seattle Beacon Hill Urban Background Site
• 30,000 vehicles per day
• Neighborhood Light Duty Vehicles

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Site Comparison Traffic Indications
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Site Comparison Traffic Indications
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Site Comparison Traffic Indications
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Traffic Data Introduction

• Traffic Data collected by WA DOT on Interstate 5
  near our Freeway (Olive Street Aethalometer) site
• Hourly Traffic Counts using a standard separation
  between Light Duty Vehicles and Heavy Duty Trucks
• We compared this data to our Aethalometer BC data
  for a period of 2 weeks during a July Stagnation
  Period

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Incorporating Speciation Data
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Site Comparisons Using Speciation Data
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Indicators

• BC ? EC ? DPM
• Harvard Research showed that the Aeth BC
  measurement is directly related and equivalent
  to the filter based EC measurement.
• Thumbrule 1.4(EC) BC measurement.
• UV ? OC ? WoodSmoke PM

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Looking at the UV Channel

• From Dr. Tony Hansens Operators Manual and from
  George Allens Research at NESCAUM
• UV BC Delta or DC
• UVPM is Qualitative, but not Quantitative.
• Absorption Cross Section of compounds that absorb
  light in the UV channel (370 nm) is highly
  variable. So this parameter DC has no physical
  engineering units.
• In the following case, we will look at 2 sites
• 1 Site where we dont expect to find a
  WoodSmoke indication
• 1 Site where we DO expect to find a WoodSmoke
  indication

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UV Channel Observations
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DC (UV-BC) Statistics Time Resolved
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DC - 30 Day Running Average
WoodSmoke Season
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DC 30 Day Running Average
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Two Ways to look at UV Channel

• DC Parameter Defined as UV BC.
• A Positive Number represents a situation when
  Wood Smoke is Present
• Using a regression of the data gathered in the
  Aethalometer, with the UV on the Y axis, and BC
  on the X axis, you get the slope of the curve.
  Defined as UV/BC.
• Numbers Greater than 1 represent Wood Smoke is
  present.
• Numbers Less than 1 represent when Diesel is
  present.

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South Tacoma Urban WoodSmoke
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Darrington Rural WoodSmoke
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Duwamish Industrial/Arterial
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Univ Washington Diesel Exposure Lab
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Summary Slide

• Dual Channel Aethalometer
• Monitoring Strategy
• Temporal Patterns and Traffic Data
• Temporal Patterns and WoodSmoke Data
• Comparisons to Speciation Data
• DC Parameter
• Using the Slope of the BC/UV correlation curve
• Acknowledgements
• Dr. Tony Hansen, George Allen, WA DOE NW, Heidi
  Curtiss, Darrington High School, Univ. Washington
  Diesel Exposure Lab