the dependence of indoor pah concentrations on outdoor pahs and traffic volume in an urban...

IntroductionMethodsResults

Conclusions

The Dependence of Indoor PAH

Concentrations on Outdoor PAHs and

Traffic Volume in an Urban Residential

Environment

B. Rey de Castro, Sc.D.

WestatRockville, Maryland USA

March 25, 2010

reyDecastro@westat.com Indoor PAHs @ Gradient

Conclusions

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

Conclusions

Outline

1 Introduction

4 Conclusions

Conclusions

PAH Health Risks

PAHs among Mobile Source Air Toxics

Potential population at risk: 17.8 million residences

Toxicity: Cancer

18th Century scrotal cancer among chimney sweepsLung cancer from occupational exposures

Toxicity: Neurodevelopment

Low birthweightRespiratory deficitsChromosomal degradationDiminished cognition

Conclusions

Monitoring SiteMeasurementsImputation of Missing Values

Outline

1 Introduction

4 Conclusions

Conclusions

Monitoring Site

Conclusions

Monitoring Site

Conclusions

Monitoring Site

Conclusions

Baltimore Traffic Study Objectives

Sustained, continuous monitoring: 12 months

High temporal resolution: 10-minute intervals

Simultaneous monitoring of traffic & covarying factors

Control expected autocorrelation: time series analysis

Conclude long-term characteristics of PAH exposure

Conclusions

Measurements

EcoChem PAS 2000Selective ionization of particle-bound PAHsAlternating indoor-outdoor 5-minute samplingCombined into 10-minute observations

Traffic

Pneumatic counter5-minute counts

Weather

Rooftop weather station (30-minute)NWS airport measurements (60-minute)

All data transformed to 10-minute observational interval

Conclusions

Imputation of Missing Values

Linear regression with reference data

Predictions substituted for missing values

Add pseudorandom variate to reduce bias

Yimpute = Ypredict + N(0, σ2)

N = 52,560

July 1, 2002 to June 30, 2003

Conclusions

Exploratory AnalysisTime Series Models

Outline

1 Introduction

4 Conclusions

Conclusions

Variability over Time

Conclusions

Workday vs. Non-Workday

Conclusions

Temperature & Dew Point

Conclusions

Mixing Height & Wind Speed

Conclusions

Models With Autocorrelation

Indoor PAHTraffic, outdoor PAHs, wind speed, wind direction,temperature, dew point, season, workdayARMA[3,3] autocorrelation

Yt,in = µin+

p∑i=1

βiXi ,t+MA(1 : 3)

AR(1 : 3)× AR(144)× AR(1008)+εt,in

Outdoor PAHTraffic, wind speed, wind direction, temperature, dewpoint, season, workdayARMA[1,1] autocorrelation

Yt,out = µout+

p∑i=1

βiXi ,t+MA(1)

AR(1)× AR(144)× AR(1008)+εt,out

Conclusions

Indoor Parameters: Treemap Visualization

Conclusions

Outdoor Parameters: Treemap Visualization

Conclusions

Wind Direction: Outdoor vs. Indoor

Indoor PAHs, SW–S–SE: 0.59 – 1.16 ng/m3Outdoor PAHs, WSW–S–NE: 0.95 – 9.78 ng/m3

Conclusions

Outline

1 Introduction

4 Conclusions

Conclusions

1 Indoor PAHs depend on both traffic volume & outdoorPAHs

2 Outdoor PAHs depend on traffic volume

3 Observed diminished effect of traffic volume in afternoon

4 Season (Spring & Summer 2003) was strongest predictorof indoor & outdoor PAHs

5 Contributions from wind direction differ between indoor &outdoor PAHs

6 Meteorology & workday had significant effects

7 Autocorrelation was significant

Conclusions

Acknowledgements

Patrick N. Breysse Timothy J. BuckleyJana N. Mihalic Alison S. Geyh

Lu Wang

EPA grant

On SlideShare: http://cli.gs/BTSpahIndoorGradient

B. Rey de Castro, Sc.D.410-929-3583

Conclusions

Summary: Quantitative

Indoor PAHs

0.57 ng/m3 per 100 vehicles every 10 minutes0.16 ng/m3 per ng/m3 outdoor PAHCombination of fresh and aged PAHs

Outdoor PAHs

3.17 ng/m3 per 100 vehicles every 10 minutes

Season (Spring & Summer 2003) was strongest predictor

Indoor PAHs: 9.27 – 9.99 ng/m3Outdoor PAHs: 9.26 – 9.78 ng/m3

Workday

Indoor PAHs: 1.64 ng/m3Outdoor PAHs: 3.01 ng/m3

Conclusions

Summary: Quantitative

MeteorologyIndoor PAHs

Wind speed: -0.38 ng/m3 per m/sTemperature: -2.48 ng/m3 per 5 CDew point: 1.87 ng/m3 per 5 C

Outdoor PAHs

Wind speed: -0.79 ng/m3 per m/sTemperature: -3.45 ng/m3 per 5 CDew point: 2.77 ng/m3 per 5 C

the dependence of indoor pah concentrations on outdoor pahs and traffic volume in an urban...

bound pahs

indoorindoor pahs

ngm3outdoor pahs

autocorrelationindoor

continuous monitoring

minute sampling

minute observational

trac volume

Technology

mechanomutable properties of a paa/pah...

pah calibration instructionsuse sitelab’s pah calibration...

health effects associated with prenatal exposure to pahs...

comparison of a bioremediation process of pahs in a pah

pahs - white paper

analytic formulas for frequency and size...

airborneexposuretopolycyclicaromatichydrocarbons(pahs

research 282 - reduction of road runoff contaminants ... ·...

chemical and bioanalytical characterisation of pah...

monitoring of polycyclic aromatic hydrocarbons (pah) in ......

assessment of polycyclic aromatic hydrocarbons (pahs) in...

chapter 5.9 polycyclic aromatic hydrocarbons (pahs) ·...

greek pahs

unbiased large spectroscopic surveys of galaxies selected by...

surfactant enhanced aquifer remediation (sear) using...

optimization and modification of new analytical methods...

data sheet pah 2/4/6.3, pah 10/12.5, pah pumps pah …data...

soot particle structure: insights from molecular dynamics...

the longitudinal dependence of indoor pah concentration on...

pcbs and pahs