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Transportation System Impacts on Bicyclists' Air Pollution Risks: Considerations for System Design...

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  • PSU Friday Transportation Seminar13 February, 2015

    Transportation System Impacts on Bicyclists' Air Pollution Risks

    Alex BigazziMiguel Figliozzi James PankowWentai Luo

    Considerations for System Design and Use

  • Framework

    2

    Vehicle Emissions

    Air Quality

    Traveler ExposureInhalation

    Uptake Health Effects

    Bicyclists' Pollution Uptake

  • Background

    3Bicyclists' Pollution Uptake

  • Bicyclists Exposures

    4

    0 5 10 15 20

    Ultrafine PM

    Fine PM

    Coarse PM

    Black Carbon

    CO

    VOC

    NO2

    # studies measuring on-road bicyclists exposure concentrations

    Pollutant 42 studies

    Bicyclists' Pollution Uptake

  • Modal Comparisons of Exposure

    Is this actionable information?

    Context-dependent results Bicyclists lower if separated

    5Bicyclists' Pollution Uptake

    vsvs

  • High-Traffic/Low-Traffic Routes

    6Bicyclists' Pollution Uptake

    -50%

    0%

    50%

    100%

    150%

    200%

    250%

    CO VOC UFP PM2.5 PM10 BC

    Expo

    sure

    Inc

    reas

    e on

    H

    igh-

    Traf

    fic R

    oute

    s

    N=6 N=11 N=8 N=6 N=3 N=5

  • Ventilation and Exercise

    7Bicyclists' Pollution Uptake

    50 100 150 200 250 Watts

    Vent

    ilatio

    n (

    liter

    /min

    ) 75

    50

    25

  • Ventilation & Bicycle Studies

    8

    57 studies assessbicyclists exposure

    Ignored38

    Constant16

    Assumed/Modeled

    15Measured

    1

    Variable3

    Modeled 2

    Measured1

    Ven

    tila

    tio

    n:

    Urban Bicyclists' Pollution Uptake

  • Bicyclist Uptake Studies

    2 studies of biomarkers:

    VOC: blood & urine Urban bikers > rural bikers

    BC: induced sputum Bicyclists > transit riders

    9Bicyclists' Pollution Uptake

  • Research Questions

    1. How does uptake vary with roadway and travel conditions?

    2. Can transport strategies reduce bicyclist uptake?

    10Bicyclists' Pollution Uptake

  • Data & Methods

    11Bicyclists' Pollution Uptake

  • Breath BiomarkersExhaled breath is a good proxy for

    blood concentrations of VOC

    12Bicyclists' Pollution Uptake

    alphaszenszor.com

    VOC in blood

  • Sampling Equipment

    13Bicyclists' Pollution Uptake

  • 1) Local roads

    Pre Breath

    Post Breath

    On-Road Sampling Segments

    20-30 minutes, 3-5 milesExposure & breath VOC

    Paired subjects

    14Bicyclists' Pollution Uptake

    Pre Breath

    Post Breath

    2) Major arterials

  • Exposure Data coverage

    15Bicyclists' Pollution Uptake

    74 breath samples

    3 subjects

    9 days

    ~40 hours of data

  • Model Development

    Exposure concentrations

    Ventilation

    Breath concentrations~ exposure + ventilation~ weather + roadway + travel conditions

    16Bicyclists' Pollution Uptake

  • Results

    17Bicyclists' Pollution Uptake

  • Results: VOC Exposure Models

    +2% per 1,000 ADT

    +20-30% in stop-and-go riding

    Off-street path +300% in industrial

    corridor

    18Bicyclists' Pollution Uptake

  • 19

    Industrial Corridor

    Bicyclists' Pollution Uptake

  • 20

    Parallel Path Comparison

    Bicyclists' Pollution Uptake

    E Burnside St. SE Ankeney St.

    N Williams Ave. NE Rodney Ave.

    Naito Pkwy. Riverside Path

  • Results: Ventilation Models

    4-8% increase in ventilation per 10 W

    Mean lag ~50 sec

    21Bicyclists' Pollution Uptake

    0 50 100 150

    0.0

    0.2

    0.4

    0.6

    0.8

    Seconds workload lagged

    Cum

    ulat

    ive im

    pact

    on ve

    ntila

    tion

    (%

    SubjecABCPooled

    %

    vent

    ilatio

    n pe

    r W

    Seconds lag

  • Breath and Exposure Concentrations

    0 1 2 3

    Breath

    Exposure

    Concentration (normalized to Park)

    Toluene

    Major arterials

    Local roads

    22Bicyclists' Pollution Uptake

  • Results: Breath Biomarkers

    8 aromatic hydrocarbons were biomarkers of traffic exposure

    Issues Background concentrations Endogenous production High water solubility

    23Bicyclists' Pollution Uptake

  • Explained variance in breath BTEX

    24Bicyclists' Pollution Uptake

    0%

    10%

    20%

    30%

    40%

    50%

    Measured variables Modeled variables

    Exposure

    Ventilation

    Exposure variability

    Weather variables

    Road & traffic

    variables

  • Applications

    25Bicyclists' Pollution Uptake

  • Steady-state biking work

    26Bicyclists' Pollution Uptake

    0

    50

    100

    150

    200

    250

    0 2 3 5 6 8 9 11 13 14 16

    Wor

    kloa

    d (W

    )

    Speed (mph)

    Rolling Resistance Drag 1% Grade

  • Inhalation and Speed

    27Bicyclists' Pollution Uptake

    0

    50

    100

    150

    200

    250

    300

    0 4 8 12 16

    Ven

    tila

    tion

    (l/

    km)

    Speed (mph)

    0% Grade2% Grade

  • Minimum-Inhalation Speed

    28Bicyclists' Pollution Uptake

    0

    5

    10

    15

    0% 2% 4% 6% 8% 10%

    Min

    imu

    m-v

    enti

    lati

    on

    spee

    d (m

    ph)

    Grade

  • Inhalation and Stops

    29Urban Bicyclists' Pollution Uptake

    0

    100

    200

    300

    400

    500

    600

    6 8 10 12 14 16 18

    Cru

    ise-

    equ

    ival

    ent

    exce

    ss

    ven

    tila

    tio

    n (

    ft)

    Cruise speed (mph)

  • Route Choice

    Detour 1 block to a bikeway vs. 1.6 blocks on a major arterial 4.3 blocks on a minor arterial

    30Bicyclists' Pollution Uptake

    ?

  • Comparison with Preferences

    31Bicyclists' Pollution Uptake

    Will bicyclists naturally minimize inhaled dose over a trip?

    Bike boulevard

    or

    neighborhood greenway

    Bike lane

    Minor arterial (no bike lane)

    Major arterial (no bike lane)

    Slightly over-avoid

    Balance on collectors (6-10k ADT) Under-avoid arterials

    Greatly over-avoid

    vs.

    vs.

    vs.

  • Exercise and Uptake

    Inhalation rate: 2-5x higher

    PM uptake: 2-5x higher

    VOC uptake: 1.5-2x higher Limited by blood/air equilibrium

    32Bicyclists' Pollution Uptake

  • Conclusions

    33Bicyclists' Pollution Uptake

  • Findings

    Determining factors

    ADT Stop-and-go riding Industrial

    corridors Speed & grade Exposure &

    ventilation

    Mitigation

    Low-volume streets

    Travel speed choice

    Reducing stops Separated

    facilities

    34Urban Bicyclists' Pollution Uptake

  • Take-Away Principles 1. Bicyclist Exposure

    a) Many different pollutantsb) Traffic, weather, and land-use all important c) Benefits of separation from traffic

    2. Bicyclist Inhalationa) Varies greatly with workload (speed, grade)b) Breath response spread out over 1-2 min

    3. Bicyclist Uptakea) For particles, highly sensitive to breathingb) For some gases, more sensitive to duration

    35Bicyclists' Pollution Uptake

  • Bikeway Design ConsiderationsBike lane High-traffic streets

    Some lateral separation Dedicated lane reduces duration in

    congestion

    Bike boulevard

    Low-traffic streets Additional benefits from traffic calming Fewer stops reduces uptake

    Cycle track Lateral separation Fewer stops reduces uptake

    Off-street path

    Low exposure (nearby industry?) Fewer stops reduces uptake

    36Bicyclists' Pollution Uptake

  • Next Steps

    Abstraction for HIA & CBA Additional biomarkers Characterizations of urban bicyclists Similar study for pedestrians Crowd-source pollution data

    37Bicyclists' Pollution Uptake

  • Crowd-Sourced Pollution Data

    38Urban Bicyclists' Pollution Uptake

  • Questions?

    [email protected]

    39Bicyclists' Pollution Uptake

    Acknowledgments Dissertation committee: Miguel

    Figliozzi, Jim Pankow, Robert Bertini, Jennifer Dill

    NITC research project with support from City of Portland and Metro

    NSF and OTREC fellowships

  • Bonus Slides!

    40Bicyclists' Pollution Uptake

  • ADT

    41Bicyclists' Pollution Uptake

  • Parallel Paths

    Burnside > Ankeny 51% TVOC, 201% CO, 9% PM2.5

    Williams > Rodney 329% TVOC, 221% CO

    Naito > McCall path 112% TVOC, 30% CO, 4% PM2.5

    42Bicyclists' Pollution Uptake

  • Explained Variance

    43Urban Bicyclists' Pollution Uptake

    0%

    10%

    20%

    30%

    40%

    50%

    60%

    BTEX Exposure Exposure variability Ventilation

    Road & traffic variables Weather variables

  • Inhalation and Grade

    44Bicyclists' Pollution Uptake

    0

    50

    100

    150

    200

    250

    300

    -2% -1% 0% 1% 2% 3% 4% 5%

    Ven

    tila

    tion

    (l/

    km)

    Grade

    11 kph18 kph

  • Minimum-ventilation envelope

    45Urban Bicyclists' Pollution Uptake

    0

    5

    10

    15

    20

    25

    30

    0% 2% 4% 6% 8% 10%

    Min

    -ven

    tila

    tio

    n v

    enti

    lati

    on

    (l

    pm

    )

    Grade

  • Results: Uptake Models

    Elasticity of breath to exposure ~0.5 Breath ~ Exposure No significant difference by subject

    Ventilation effect small but significant for some compounds Elasticity of 0.1-0.2

    46Bicyclists' Pollution Uptake

    Transportation System Impacts on Bicyclists' Air Pollution RisksFrameworkBackgroundBicyclists ExposuresModal Comparisons of ExposureHigh-Traffic/Low-Traffic RoutesVentilation and ExerciseVentilation & Bicycle StudiesBicyclist Uptake StudiesResearch QuestionsData & MethodsBreath BiomarkersSampling EquipmentOn-Road Sampling SegmentsExposure Data coverageModel DevelopmentResultsResults: VOC Exposure ModelsIndustrial CorridorParallel Path ComparisonResults: Ventilation ModelsBreath and Exposure ConcentrationsResults: Breath BiomarkersExplained variance in breath BTEXApplicationsSteady-state biking workInhalation and SpeedMinimum-Inhalation SpeedInhalation and StopsRoute ChoiceComparison with PreferencesExercise and UptakeConclusionsFindingsTake-Away Principles Bikeway Design ConsiderationsNext StepsCrowd-Sourced Pollution DataQuestions?Bonus Slides!ADTParallel PathsExplained VarianceInhalation and GradeMinimum-ventilation envelopeResults: Uptake Models

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PSU Friday Transportation Seminar 13 February, 2015 Transportation System Impacts on Bicyclists' Air Pollution Risks Alex Bigazzi Miguel Figliozzi James Pankow Wentai Luo Considerations for System Design and Use
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