EXPOSURE ASSESSMENT

PAG MEETING, 14/07/2003SURREY UNIVERSITY

DDispersion

EEmissions

MMovement

Buildings

Synoptic Meteorology

Vehicle-Induced

Turbulence

Road

Design

Determinants of exposure

- apply to determinants of temporal variability in exposure averaged over a population,

as well as variation of time-averaged exposure across population

Exposure Volunteers!

Typical Timings

Exposure Routes

Route 1 : Marylebone Road, heavily trafficked

Route 2 : back streets with crossings of Marylebone Road

Digital Data © Geoinformation Group (2002)

Equipment

CO T15 Langan - Measures carbon monoxide every 10 seconds

Casella Ultraflow Pump + Filter - average PM2.5 conc.

TSI P-Trak - Measures ultrafine particles every second

Modes of Transport:People Power - Walking & Cycling

Mechanical Transport – Car, Bus & Taxi

Walking & CyclingRoutes 1 & 2, 06/05/03 a.m. (40-minute journeys)

Peaks crossing Marylebone Rd, otherwise in general 25% less pollution in backstreets

People walking along Marylebone Rd experience peak particulate pollution approx 50% less than those cycling

DDispersion

EEmissions

MMovement

Buildings

Synoptic Meteorology

Vehicle-Induced

Turbulence

Road

Design

Measurements to understand determinants of exposure in more detail

• Speciated measurements (PM2.5 and VOCs)• Spatial variability over a common averaging time, including indoor/outdoor ratios• Time-series at a fixed point• Measurement of sensitivity to parameters that can be controlled•Visualisation of relationship between exposure and activity

Elemental carbon

• Each PM2.5 filter, in addition to weighing for total mass, has reflectance measured

• Paired samples for reflectance and laboratory analysis exposed at variety of representative fixed locations, with Quartz filters sent for laboratory analysis for elemental carbon

• Awaiting results from lab, but quality check has discovered correction factor to apply to mass on PTFE filters

• Elemental carbon shows more spatial variability than total mass

Indoor (WCC) / Outdoor

Variations in indoor and outdoor particulates and VOCs between:• WCC rooms on different levels; and • with different aspects2 MSc projects

Summary of preliminary VOC measurements (BRE)

• Outdoor spatial variability greater than limited measurement of temporal variability

• Different speciation indoors to outdoors, especially in one room obviously strongly dominated by indoor sources

• Is indoor temporal variability greater than street canyon temporal variability?

• What are the implications of this for using outdoor background measurements as a surrogate for exposure?

1st Deployment: 5-VOC Concentrations Indoor & Outdoor Locations

3.23.8

2.6 2.7 2.71.8

9.2

1.2 1.5

0.3 0.5

3.1

0.3 0.3 0.61.7 2.0

6.3

4.75.6

4.95.7

11.5

5.4

3.3

18.8

27.2

<0.1<0.1<0.1<0.1<0.1<0.1 <0.1

64.4

<1.4<1.4

<1.41.4

1.4

0

10

20

30

40

50

60

70

R1-1A R1-1B R2-2A R2-2B R3-3A R2-2 3GF 5

INDOOR OUTDOOR

Locations

VO

C C

on

ce

ntr

ati

on

s (

g

m-3)

Hexanal m,p-Xylene n-Propylbenzene Styrene Toluene

2.5

0.3

5.6

<0.1

<1.6

0246810

R2-2B 6A R2-2 3GF

INDOOR OUTDOOR

3.0

1.02.0

5.8

<0.1

0246810

R2-2B 6A R2-2 3GF

INDOOR OUTDOOR

Stationary Exp – Waiting at Crossing22 May 03

Adults waiting on the pavement are exposed to over 50% less particulate matter than if waiting in the central reservation – cyclical nature with traffic lights.

Children would be receiving a higher dose due to their proximity to the pollution source.

VisualisationHealth & Safety Lab, Sheffield

Video camera deployed with PTraks which can be incorporated via newvizcd visualisation software