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Near-Roadway Exposure and Health

Chad BaileyU. S. EPA

Office of Transportation and Air QualityPresentation for Air Toxics Workshop II

Houston, Texas, June 12, 2007

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Key Points

• A significant fraction of the U.S. population lives very close to “major roads”

• Concentrations of PM2.5, ultrafines, PAH, and toxics are significantly higher near traffic

• In >>100 studies since late 1990s, living in proximity to heavy traffic is associated with significant increases in:– Cardiovascular effects– Prevalence of respiratory conditions and symptoms– Adverse birth outcomes (LBW, etc.)

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Cumulative Population Fraction within X Meters of "Major Roads""Major Road" Definitions Shown in Legend

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Distance (m) from "Major Road" as Defined in Legend

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HAPEM6 - "Major Road" - CensusDefinition - No Cutoff

Garshick et al. (2003) - "MajorRoad" - No Cutoff

Garshick et al. (2003) - >=10kAADT Cutoff

McConnell et al. (2006) - Freeway,highway, or arterial

American Housing Survey(Housing Units) -- 4 Lane Highway,Airport, or RailroadRyan et al. (2007) - "Major Road" -No Cutoff

Ryan et al. (2007) - Bus Routes

American Housing Survey results pertain to housing units, not population.

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Health Effects

Note: this is just a snapshot; please ask if you’d like a copy of

the whole bibliography

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Near-Roadway Health Effects

• Residence or school near major roadways has been associated with:– Cardiovascular morbidity– Respiratory symptoms and conditions (e.g.

asthma)

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Cardiovascular Effects

• Tonne et al. (2006) – Worcester, MA– Acute myocardial infarction associated with

increased traffic near home and closer proximity to a major roadway

• Hoffman et al. (2006) – Germany– 85% increase in prevalence of coronary

heart disease among residents living within roads with >30k AADT

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Children’s Respiratory Health

• Cohort Studies– Southern California Children’s Health Study

• McConnell et al. (2005) reported that residence within 75 m of a major road was associated with increased risk of lifetime asthma, current asthma, and wheeze. Higher risks among those children with no family history.

• Gauderman et al. (2006) reported that children growing up within 500 m of a freeway had deficits in lung growth between ages 10 and 18 years

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Adverse Birth Outcomes – Specific Air Toxics (PAHs)

• Columbia Mothers and Newborns Study– Perera et al. (2003)

• Measured PAH exposures in pregnant women in New York City associated with low birth weight and reduced head circumference

– Miller et al. (2005)• Follow-up in birth cohort to Perera et al.• Maternal exposure to PAH during pregnancy associated with increase

risk of wheeze and “probable asthma” by age 2 in homes with ETS– Bocskay et al. (2004)

• Maternal exposure to PAH during pregnancy associated with elevated concentrations of “stable chromosomal aberrations” in umbilical cord blood lymphocytes

• Predictive of long-term cancer mortality in other studies– Perera et al. (2006)

• Prenatal PAH exposure associated with lower mental development scores at age 3

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Air Quality & Exposure

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Near-roadway PM distribution

• I-405 Freeway (Los Angeles)– Other studies in

Cincinnati, OH, Raleigh, NC, New York, NY, Europe, Australia

• High numbers of particles near roadway indicate fresh emissions

Distance (m) from I-405

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EPA Funded the Development of a RIOPA GIS Database

• Weisel, C.P. Assessment of the Contribution to Personal Exposures of Air Toxics from Mobile Sources. Final Report to EPA Office of Transportation and Air Quality, 2004.

• Kwon, J. Development of a RIOPA Database and Evaluation of the Effect of Proximity on the Potential Residential Exposure to VOCs from Ambient Sources. PhD Dissertation, Rutgers University, New Brunswick, NJ, 2005.

• Kwon, J.; Weisel, C.P.; Turpin, B.J.; et al. (2006) Source proximity and outdoor-residential VOC concentrations: results from the RIOPA study. Environ Sci Technol 40: 4074-4082.

• Liu, W.; Zhang, J.; Kwon, J.; et al. (2007) Concentrations and source characteristics of airborne carbonyl compounds measured outside urban residences. J Air & Waste Manage Assoc 56: 1196-1204.

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Criteria and Hazardous Air Pollutant Trends – RIOPA(EPA Final Report – Elizabeth, NJ Results)

Coronene vs. Urban InterstatePM2.5 v. Urban Interstate, Truck Loading, Local Rd.

Benzene v. Urban Arterial, Gas Station MTBE v. Urban Interstate, Gas Station

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Air Toxics Near RoadwaysHighway Tollbooth

Baltimore, MD

y = 5E-05x + 0.2869

R2 = 0.42

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Annual Average Daily Traffic on Nearest Major Collector (FRC5)

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Fresno, CA

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Key Questions

• How do all these microscale effects add up?

• Are they relevant for large segments of the general population

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NYC Land Use RegressionRoss et al. (2007) Atmos Environ 41: 2255–2269

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Stopping Point

• Millions of Americans live near major roadways

• Concentrations of criteria and hazardous air pollutants are elevated near roadways

• In urban areas, nearby traffic and other sources are major drivers of ambient concentrations of air pollution

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What Analytical Tools Are Available?

What tools are available to assess these concerns?

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Emissions• Exhaust/Evaporative/Tire & Brake Wear

– MOBILE6.2: emission factor model (g/mi)– HC, CO, NOx, toxics, PM10, PM2.5– Requires local information on fleet composition (MPO

or on-site collection), fuel properties, I&M, road types, average speeds

– Can be run for individual road links or for entire modeling domain

– Key limitation: PM emission factors (ONLY) not sensitive to speed

• Nonroad engines– NONROAD model and documentation– Emission Factors for Locomotives (EPA420-F-97-051)

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Emissions

• Road dust– AP-42, Chapter 13– Alternate local methods if approved by

EPA

• MOVES– EPA’s next-generation emission factor

model– Improved local detail, due to modal basis

of emission prediction (e.g. idle, accel)

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Dispersion Models

• Roadway Sources– Line source dispersion models

• CALINE3/4, CAL3QHC, UCD2001

– Fast numerical models• QUIC

• Terminals, Rail Yards, other semi-stationary sources– AERMOD: EPA’s multisource model

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Dispersion Model Outputs

R. Baldauf, 2007

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How do EPA emission standards affect these concerns?

• EPA’s recent mobile source rules will dramatically reduce the emissions of criteria and toxic pollutants over the next decade

• This is expected to reduce exposures to many pollutants

• However, other exposure agents (e.g. road and tire dust) may continue to grow over time– Near-roadway epidemiology studies do not use

exposure indicators with source-specificity

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Conclusions

• A significant fraction of the U.S. population lives near major roadways

• Numerous air pollutant levels are elevated near major roadways and other transportation infrastructure

• Living (working/studying) near traffic is associated with a range of adverse health outcomes

• The extent to which emission standards solve the problems is still an open question