EXPOSURE ASSESSMENT

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EXPOSURE ASSESSMENT

• S Kaur, M Nieuwenhuijsen, R Colvile

Department of Environmental Science Technology
Imperial College London, UK
DAPPLE Science Meeting 30th November 2004
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Aims Objectives

• Characterise and evaluate human exposure levels
  at and around a street canyon intersection to CO
  and fine particulate matter
• Assess variations in exposure between and within
  i) modes of transport, ii) routes and iii)
  timings
• Examine the relationship between human exposure
  to PM2.5 and CO at and around a street canyon
  intersection in relation to fixed site monitored
  concentrations
• Identify and quantify the main determinants of
  human exposure at and around a street canyon
  intersection
• Consider the policy implications arising from the
  research

DAPPLE Science Meeting 30th November 2004
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2003 Field Measurements
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Results Data Capture

• 481 samples collected, 394 acceptable samples

Overall Exposure to Pollutant N AM A SD Min. Max.
PM2.5 (µg/m3) 197 33.6 14.5 5.3 77.5
Ultrafine Particle Counts (pt/cm3) 86 88101 31291 36474 178601
CO (ppm) 111 1.0 0.7 0.0 2.9
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Results Timings
    PM2.5 (µg/m)   Ultrafine Particle Counts (pt/cm3) Ultrafine Particle Counts (pt/cm3) Ultrafine Particle Counts (pt/cm3)   CO (ppm)  
Timing 1 2 3 1 2 3 1 2 3
Timing (8.30am) (12.00pm) (3.15pm) (8.30am) (12.00pm) (3.15pm) (8.30am) (12.00pm) (3.15pm)
N 61 63 61 31 28 27 37 38 36
AM 34.6 28.8 35.6 106270 79188 76483 1.5 0.7 0.8
ASD 14.1 12.3 14.8 34075 25487 23818 0.7 0.5 0.5
Min. 12.5 6.0 5.3 52530 36679 36474 0.2 0.0 0.0
Max. 66.5 55.9 77.5 178601 128979 127326 2.9 2.0 1.8
DAPPLE Science Meeting 30th November 2004
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Results Modes of Transport
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Results Routes
    N AM A SD Min. Max.
PM2.5 (µg/m3) PM2.5 (µg/m3)
Marylebone Road Circuit 100 35.3 14.0 6.0 77.5
Gloucester Place Backstreets 97 31.8 14.7 5.3 71.8
Ultrafine Particle Count (pt/cm3) Ultrafine Particle Count (pt/cm3)
Marylebone Road Circuit 48 101142 29186 47300 178601
Gloucester Place Backstreets 38 71628 25844 36474 158685
Carbon Monoxide (ppm) Carbon Monoxide (ppm)
Marylebone Road Circuit 61 1.3 0.6 0.4 2.9
  Gloucester Place Backstreets 50 0.6 0.5 0.0 2.0
DAPPLE Science Meeting 30th November 2004
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Correlations between Pollutants
DAPPLE Science Meeting 30th November 2004
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Ambient Monitoring
DAPPLE Science Meeting 30th November 2004
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Results Other
DAPPLE Science Meeting 30th November 2004
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Data Analysed/Available (2003)
DAPPLE Science Meeting 30th November 2004
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Aims Objectives

• Characterise and evaluate human exposure levels
  at and around a street canyon intersection to CO
  and fine particulate matter?
• Assess variations in exposure between and within
  i) modes of transport, ii) routes and iii)
  timings ?
• Examine the relationship between human exposure
  to PM2.5 and CO at and around a street canyon
  intersection in relation to fixed site monitored
  concentrations ?
• Identify and quantify the main determinants of
  human exposure at and around a street canyon
  intersection
• Consider the policy implications arising from the
  research

DAPPLE Science Meeting 30th November 2004
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2004 Field Measurements
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2004 Field Data Status
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Analysis of Determinants of Exp.

• Identify and quantify the determinants of
  exposure
• Regression the model assumes personal exposure
  is a function of independent variables (e.g. wind
  speed, wind direction, traffic densityetc) with
  a normally distributed random error
• Dependent on meteorological and traffic data
  availability
• Start with 2003 data

DAPPLE Science Meeting 30th November 2004
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Timeline

• Nov 2004 Descriptive work for 2003 data
  complete
• Dec 2004 Start data collection for regression
  analysis from other groups
• Jan 2005 Descriptive work for 2004 data
  complete
• Mar/Apr ? 2005 Basic analysis of determinants
  of exposure for 2003 data complete
• ????? Detailed analysis of determinants for 2003
  data
• ????? Analysis of determinants for 2004 data

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Collaborators

• Health Safety Laboratory, Sheffield (2003
  2004) exposure visualisation
• UCL testing GPS and CO sensors
• NERI requested fieldwork completed, awaiting
  funding

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Bus Measurements

• Top graph example of timeseries ultrafine
  particle count at a bus stop (westbound,
  downstream of DAPPLE site on number 18 route)
  including peaks associated with arrival and
  departure of buses
• Lower graph average timeseries ultrafine
  particle count measured on multiple journeys
  between Edgware Road and Regents Park stations on
  number 18 route, including the section through
  the DAPPLE site.
• Use of data to model exposure
• Combine concentration at bus stop with total
  waiting time and number of people waiting
• Combine concentration on bus with journey time
  and bus occupancy
• Note that most people experience the more
  polluted, delayed journeys! Clean buses have
  nobody on them!

DAPPLE Science Meeting 30th November 2004