Childhood Asthma and Exposure to Traffic and Nitrogen Dioxide

Gauderman, W. James; Avol, Edward L.; Lurmann, Fred; Küenzli, Nino; Gilliland, Frank D.; Peters, John; McConnell, Rob

doi:10.1097/01.ede.0000181308.51440.75

Cited by 452 publications

(365 citation statements)

References 35 publications

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“…The 5-km radius was used previously, and reasonable agreement was observed between CALINE4-modeled and measured 2-week average NO 2 concentrations at 260 residences in southern California (R 2 ϭ 0.3-0.9). 22 The CALINE4 model is a gaussian line source dispersion model designed to estimate local pollutant concentrations from motor vehicle emissions based on traffic volumes, roadway geometry, vehicle emission rates, and meteorologic conditions (wind speed and direction, atmospheric stability, and mixing heights). 23 Wind patterns affect the general direction and dispersion of pollutants, leading to different exposures for individuals on the upwind vs downwind side of traffic sources.…”

Section: Exposure Evaluationmentioning

confidence: 99%

Repeated hospital encounters for asthma in children and exposure to traffic-related air pollution near the home

Delfino

Chang

et al. 2009

Annals of Allergy, Asthma & Immunology

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Background: Aggregate hospital encounters for asthma (admissions or emergency department visits) have been associated with daily regional air pollution. There are fewer data on relationships between repeated hospital encounters and traffic-related air pollution near the home.Objective: To estimate the association of local traffic-generated air pollution with repeated hospital encounters for asthma in children.Methods: Hospital records for 2,768 children aged 0 to 18 years (697 of whom had Ն2 encounters) were obtained for a catchment area of 2 hospitals in northern Orange County, California. Residential addresses were geocoded. A line source dispersion model was used to estimate individual seasonal exposures to local traffic-generated pollutants (nitrogen oxides and carbon monoxide) longitudinally beginning with the first hospital encounter. Recurrent proportional hazards analysis was used to estimate risk of exposure to air pollution adjusting for sex, age, health insurance, census-derived poverty, race/ethnicity, residence distance to hospital, and season. The adjustment variables and census-derived median household income were tested for effect modification.Results: Adjusted hazard ratios for interquartile range increases in nitrogen oxides (4.00 ppb) and carbon monoxide (0.056 ppm) were 1.10 (95% confidence interval, 1.03-1.16) and 1.07 (1.01-1.14), respectively. Associations were strongest for girls and infants but were not significantly different from other groups. Stronger associations in children from higher-income block groups (P Ͻ .09 for trend) may have been due to more accurate data.Conclusions: Associations for repeated hospital encounters suggest that locally generated air pollution near the home affects asthma severity in children. Risk may begin during infancy and continue in later childhood, when asthma diagnoses are clearer.

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Section: Exposure Evaluationmentioning

confidence: 99%

Repeated hospital encounters for asthma in children and exposure to traffic-related air pollution near the home

Delfino

Chang

et al. 2009

Annals of Allergy, Asthma & Immunology

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“…1 The underlying mechanisms for both cardiovascular and respiratory illnesses suggest that peak exposures in especially dense traffic areas (or resulting from unusual short-term weather events such as inversions) may act together with long-term somewhat lower level exposures to contribute to underlying vulnerability and then more severe events such as asthma attacks or myocardial infarction, especially among individuals with pre-existing health conditions. 17,50 Some traffic count data are available on an hourly basis from a smaller number of reporting stations. Assessment of health effects associated with peak traffic levels could be examined for individuals with localized exposures during those periods.…”

Section: Rationale For Using Surrogate Methods For Characterizing Tramentioning

confidence: 99%

“…Many studies have focused on measuring and/or modeling the individual pollutants or classes of pollutants in traffic emissions including nitrogen dioxide (NO 2 ), carbon monoxide (CO), fine particulate matter less than or equal to 2.5 μm in aerodynamic diameter (PM 2.5 ), ultrafine particulates less than or equal to 0.1 μm in aerodynamic diameter (UFP), the elemental carbon content of PM, black carbon (BC), or volatile organic compounds such as benzene and toluene, attempting to identify the specific causal agent associated with adverse health effects. [16][17][18][19] These studies have been conducted by positioning equipment on a residence or school building, in mobile vans, on carts that follow individuals through the course of their day, or in packs worn by study participants. [20][21][22] Air monitors have also been positioned at locations across a larger study area and data combined with statistical interpolation models, land-use regression models, dispersion models, meteorological-emission models, or some hybrid of these to estimate exposure concentrations for individuals in the study.…”

Section: Introductionmentioning

confidence: 99%

Characterizing Urban Traffic Exposures Using Transportation Planning Tools: An Illustrated Methodology for Health Researchers

et al. 2010

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Exposure to elevated levels of vehicular traffic has been associated with adverse cardiovascular and respiratory health effects in a range of populations, including children, the elderly, and individuals with pre-existing heart conditions, diabetes, obesity, and genetic susceptibilities. As these relationships become clearer, public health officials will need to have access to methods to identify areas of concern in terms of elevated traffic levels and susceptible populations. This paper briefly reviews current approaches for characterizing traffic exposure and then presents a detailed method that can be employed by public health officials and other researchers in performing screening assessments to define areas of potential concern within a particular locale and, with appropriate caveats, in epidemiologic studies examining traffic-related health impacts at the intra-urban scale. The method is based on two exposure parameters extensively used in numerous epidemiologic studies of traffic and health-proximity to high traffic roadways and overall traffic density. The method is demonstrated with publically available information on susceptible populations, traffic volumes, and Traffic Analysis Zones, a transportation planning tool long used by Metropolitan Planning Agencies and planners across the USA but presented here as a new application which can be used to spatially assess possible traffic-related impacts on susceptible populations. Recommendations are provided for the appropriate use of this methodology, along with its limitations.

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“…For example, Weiland et al (1994) use this term in conjunction with self-described truck-traffic frequencies and ''main'' vs. ''side'' streets, whereas in California (Gunier et al, 2003;Gauderman et al, 2005) and in the Veterans Cohort Study (Lipfert et al, 2006a, b), more explicit continuous measures based on annual traffic counts within a specified land area were used.…”

Section: Traffic Exposure Metricsmentioning

confidence: 99%

“…The minimum distance to ''major'' roadways was 6 m in the study of Schikowski et al (2005), for which the ''high''-exposure group (18.5%) was defined as within 100 m. Thus, given the exponential decay of pollutant concentrations downwind of roadways, it is clear that actual residential exposures may vary substantially, even within ''high''-exposure subsets. A few studies have used proximity to roadways as a continuous rather than a categorical predictor variable (see Gauderman et al, 2005, for example). However, it is not always clear whether ''distance from a roadway'' is defined on the basis of the roadway centerline or its edge, which may be an important consideration when modeling situations of close proximity.…”

Section: Exposure Measurements and Distributionsmentioning

confidence: 99%

On exposure and response relationships for health effects associated with exposure to vehicular traffic

Lipfert

Wyzga

2008

J Expo Sci Environ Epidemiol

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This work examines various metrics and models that have been used to estimate long-term health effects of exposure to vehicular traffic. Such health impacts may include effects of air pollution due to emissions of combustion products and from vehicle or roadway wear, of noise, stress, or from socioeconomic effects associated with preferred residential locations. Both categorical and continuous exposure metrics are considered, typically for distances between residences and roadways, or for traffic density or intensity. It appears that continuous measures of exposure tend to yield lower risk estimates that are also more precise than categorical measures based on arbitrary criteria. The selection of appropriate exposure increments to characterize relative risks is also important in comparing pollutants and other agents. Confounding and surrogate variables are also important issues, since studies of traffic proximity or density cannot identify the specific agents related to traffic exposures that might be responsible for the various health endpoints that have been implicated. Studies based on ambient air quality measurements are necessarily restricted to species for which data are available, some of which may be serving as markers for the actual agents of harm. Studies based on modeled air quality are limited by the accuracy of mobile source emission inventories, which may not include poorly maintained (high emitting) vehicles. Additional exposure modeling errors may result from precision limitations of geocoding methods. Studies of the health effects of traffic are progressing from establishing the existence of relationships to describing them in more detail, but effective remedies or control strategies have generally not yet been proposed in the context of these epidemiological studies. Resolution of these dose-response uncertainties is important for the development of effective public health strategies for the future.

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Childhood Asthma and Exposure to Traffic and Nitrogen Dioxide

Abstract: These results indicate that respiratory health in children is adversely affected by local exposures to outdoor NO2 or other freeway-related pollutants.

Cited by 452 publications

References 35 publications

Repeated hospital encounters for asthma in children and exposure to traffic-related air pollution near the home

Repeated hospital encounters for asthma in children and exposure to traffic-related air pollution near the home

Characterizing Urban Traffic Exposures Using Transportation Planning Tools: An Illustrated Methodology for Health Researchers

On exposure and response relationships for health effects associated with exposure to vehicular traffic

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