The Longitudinal Dependence of Indoor PAH Concentration on Outdoor PAH and Traffic Volume in an...

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The influence of traffic volume and ambient outdoor PAH on indoor PAH exposure was quantified at the Baltimore Traffic Study site, an unoccupied attached 2nd-floor apartment in an inner-city neighborhood "hot spot" surrounded by urban roadways that together carry over 150,000 vehicles per day. Monitoring of outdoor and indoor particle-bound PAH and traffic volume was conducted continously for 12 months at 10-minute intervals (n = 52,560). Time-series modeling accounted for complex and extensive autocorrelation. Vehicle count (0.57 [SE=0.04] ng/m3 per 100 vehicles every ten minutes) and outdoor PAH (0.16 [0.001] ng/m3 per ng/m3 outdoor PAH) are statistically significant predictors of indoor PAH, in addition to a mean background indoor exposure without indoor sources of 9.07 ng/m3. Spring 2003 (9.99 [0.67] ng/m3) and Summer 2003 (9.27 [+/-1.27] ng/m3) are associated with the greatest increases in indoor PAH, relative to Summer 2002. An additional 1.64 [0.27] ng/m3 is attributable to work days. Winds from the SW-S-NE quarter, which would have entrained PAH from Baltimore's densely trafficked central business district and a nearby interstate highway, contribute significantly to indoor PAH (0.31 - 1.16 ng/m3). Dew point, outdoor temperature, and wind speed are also statistically significant predictors. Indoor PAH's short-term autocorrelation is ARMA[3,3], where lag 3 indicates that PAH concentrations are correlated for up to 30 minutes. Significant autoregressive correlation at lags 144 and 1008 indicate autocorrelations at diurnal and weekly cycles, respectively. In a separate time series model, it was established that outdoor PAH itself depends at a statistically significant on vehicle count at a rate of 3.17 [0.11] ng/m3 per 100 vehicles every ten minutes. Conclusion: local indoor & outdoor exposure to PAH from mobile sources is substantially modified by meteorologic and temporal conditions, including atmospheric transport processes. PAH concentration also demonstrates statistically significant autocorrelation at several timescales.

Transcript of The Longitudinal Dependence of Indoor PAH Concentration on Outdoor PAH and Traffic Volume in an...

IntroductionMethodsResults

ConclusionsCoda

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

April 12, 2010

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

5 Coda

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

5 Coda

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

5 Coda

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

Monitoring Site

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

Monitoring Site

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

Monitoring Site

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

Measurements

PAHs

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Monitoring SiteMeasurementsImputation of Missing Values

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

5 Coda

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Variability over Time

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Workday vs. Non-Workday

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Temperature & Dew Point

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Mixing Height & Wind Speed

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Indoor Parameters: Treemap Visualization

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

Outdoor Parameters: Treemap Visualization

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Exploratory AnalysisTime Series Models

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

5 Coda

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Acknowledgements

Johns Hopkins Bloomberg School of Public Health

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

EPA grant

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Outline

1 Introduction

2 MethodsMonitoring SiteMeasurementsImputation of Missing Values

3 ResultsExploratory AnalysisTime Series Models

4 Conclusions

5 Coda

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Other Work

The Longitudinal Dependence of Black CarbonConcentration on Traffic Volume in an UrbanEnvironment. JAWMA, 2008

New Haven air pollution reduction and public healthindicators. Prepared under contract to the US EPA, 2008

Gastrointestinal illness associated with water exposure.Prepared under contract to the US EPA, 2007.

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Other Work

The Longitudinal Dependence of Black CarbonConcentration on Traffic Volume in an UrbanEnvironment. JAWMA, 2008

New Haven air pollution reduction and public healthindicators. Prepared under contract to the US EPA, 2008

Gastrointestinal illness associated with water exposure.Prepared under contract to the US EPA, 2007.

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Other Work

The Longitudinal Dependence of Black CarbonConcentration on Traffic Volume in an UrbanEnvironment. JAWMA, 2008

New Haven air pollution reduction and public healthindicators. Prepared under contract to the US EPA, 2008

Gastrointestinal illness associated with water exposure.Prepared under contract to the US EPA, 2007.

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Other Work

A Method for Obtaining Microenvironment ExposureWeights From a Straightforward Statistical Model ofTime-Location Data. [under review at JESEE].

Estrogenic Activity of Polychlorinated Biphenyls Presentin Human Tissue and the Environment. ES&T, 2006

The Statistical Performance of an MCF-7 Cell CultureAssay Evaluated Using Generalized Linear Mixed Modelsand a Score Test. Statistics in Medicine, 2007

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Other Work

A Method for Obtaining Microenvironment ExposureWeights From a Straightforward Statistical Model ofTime-Location Data. [under review at JESEE].

Estrogenic Activity of Polychlorinated Biphenyls Presentin Human Tissue and the Environment. ES&T, 2006

The Statistical Performance of an MCF-7 Cell CultureAssay Evaluated Using Generalized Linear Mixed Modelsand a Score Test. Statistics in Medicine, 2007

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Other Work

A Method for Obtaining Microenvironment ExposureWeights From a Straightforward Statistical Model ofTime-Location Data. [under review at JESEE].

Estrogenic Activity of Polychlorinated Biphenyls Presentin Human Tissue and the Environment. ES&T, 2006

The Statistical Performance of an MCF-7 Cell CultureAssay Evaluated Using Generalized Linear Mixed Modelsand a Score Test. Statistics in Medicine, 2007

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

Contact

B. Rey de Castro, Sc.D.Baltimore, Maryland USA

rey.decastro@comcast.net410-929-3583

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA

IntroductionMethodsResults

ConclusionsCoda

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

reyDecastro@westat.com Indoor PAHs @ US EPA