Association between traffic volume and health care use for asthma among residents at a U.S.-Canadian border crossing point

Monitoring of air pollution levels related to Charilaos Trikoupis Bridge

Charilaos Trikoupis bridge is the longest cable bridge in Europe that connects Western Greece with the rest of the country. In this study, six air pollution monitoring campaigns (including major regulated air pollutants) were carried out from 2013 to 2015 at both sides of the bridge, located in the urban areas of Rio and Antirrio respectively. Pollution data were statistically analyzed and air quality was characterized using US and European air quality indices. From the overall campaign, it was found that air pollution levels were below the respective regulatory thresholds, but once at the site of Antirrio (26.4 and 52.2μg/m³ for PM_2.5 and ΡΜ₁₀, respectively) during the 2nd winter period. Daily average PM₁₀ and PM_2.5 levels from two monitoring sites were well correlated to gaseous pollutant (CO, NO, NO₂, NO_x and SO₂) levels, meteorological parameters and factor scores from Positive Matrix Factorization during the 3-year period. Moreover, the elemental composition of PM₁₀ and PM_2.5 was used for source apportionment. That analysis revealed that major emission sources were sulfates, mineral dust, biomass burning, sea salt, traffic and shipping emissions for PM₁₀ and PM_2.5, for both Rio and Antirrio. Seasonal variation indicates that sulfates, mineral dust and traffic emissions increased during the warm season of the year, while biomass burning become the dominant during the cold season. Overall, the contribution of the Charilaos Trikoupis bridge to the vicinity air pollution is very low. This is the result of the relatively low daily traffic volume (~10,000 vehicles per day), the respective traffic fleet composition (~81% of the traffic fleet are private vehicles) and the speed limit (80km/h) which does not favor traffic emissions. In addition, the strong and frequent winds further contribute to the rapid dispersion of the emitted pollutants.

Spatiotemporal patterns of childhood asthma hospitalization and utilization in Memphis Metropolitan Area from 2005 to 2015

OBJECTIVE

To identify the key risk factors and explain the spatiotemporal patterns of childhood asthma in the Memphis metropolitan area (MMA) over an 11-year period (2005-2015). We hypothesize that in the MMA region this burden is more prevalent among urban children living south, downtown, and north of Memphis than in other areas.

METHODS

We used a large-scale longitudinal electronic health record database from an integrated healthcare system, Geographic information systems (GIS), and statistical and space-time models to study the spatiotemporal distributions of childhood asthma at census tract level.

RESULTS

We found statistically significant spatiotemporal clusters of childhood asthma in the south, west, and north of Memphis city after adjusting for key covariates. The results further show a significant increase in temporal gradient in frequency of emergency department (ED) visits and inpatient hospitalizations from 2009 to 2013, and an upward trajectory from 4 per 1,000 children in 2005 to 16 per 1,000 children in 2015. The multivariate logistic regression identified age, race, insurance, admit source, encounter type, and frequency of visits as significant risk factors for childhood asthma (p < 0.05). We observed a greater asthma burden and healthcare utilization for African American (AA) patients living in a high-risk area than those living in a low-risk area in comparison to the white patients: AA vs. white [odds ratio (OR) = 3.03, 95% confidence interval (CI): 2.75-3.34]; and Hispanic vs. white (OR = 1.62, 95% CI: 1.21-2.17).

CONCLUSIONS

These findings provide a strong basis for developing geographically tailored population health strategies at the neighborhood level for young children with chronic respiratory conditions.

On-Roadway In-Cabin Exposure to Particulate Matter: Measurement Results Using Both Continuous and Time-Integrated Sampling Approaches

The Atlanta Commuters Exposure (ACE) Study was designed to measure in-cabin exposure to roadway particulate pollution and acute health response in a panel of adults with and without asthma following a 2-h scripted route along major highways in Atlanta. This article focuses on methods and results of both continuous and integrated approaches used to measure the concentration of PM_2.5 mass, particle number concentration (PNC), black carbon (BC) mass, and particle-bound PAHs, in-cabin noise, PM elemental composition, elemental carbon, organic carbon, water-soluble organic carbon (WSOC) content, and speciation of a broad range of organic compounds including alkanes, hopanes, and PAHs. Speciated PM data indicates that in-cabin particles derive from three non-co-varying processes: the resuspension of road dust containing crustal elements and previously-deposited brake pad residue with a contribution of normal fuel combustion, incomplete combustion processes producing PAHs and carbon particles, and particles ablated from brake pads that have not previously deposited to the roadside environment. Most in-cabin pollutants were elevated during the warm season with the notable exception of PNC. PNC was not found to be correlated with most other pollutants. In-cabin concentrations were marginally higher when windows were open.

Proximity to major roadways is a risk factor for airway hyper-responsiveness in adults

BACKGROUND

Proximity to major roads is reported to be associated with asthma and airway hyper-responsiveness in children. Similar studies using objective measurements in adults are not available in Canada.

OBJECTIVE

To test the hypothesis that adult asthmatic patients who live close to major roads and highways in an urban environment are at a risk of moderate to severe airway hyper-responsiveness.

METHODS

Airway responsiveness was determined using methacholine bronchial provocation (PC(20)) tests in a cohort of 2625 patients who attended an outpatient clinic in Hamilton, Ontario. Patient addresses were geocoded in a geographic information system to determine proximity to major roads and highways. Multivariate linear and multinomial regression analyses were used to assess whether proximity to roads was a risk factor for airway hyper-responsiveness as measured by PC(20) methacholine.

RESULTS

Patients who lived within 200 m of a major road had increased odds (OR 1.38 [95% CI 1.04 to 1.85]) of having moderate airway hyperresponsiveness (0.25 mg⁄mL <PC(20) <2.0 mg/mL) compared with having a normal response (PC(20) >16 mg/mL). Spatial analysis also revealed that the majority of patients with severe airway hyper-responsiveness lived within the urban core of the city while those with moderate to mild hyper-responsiveness were also dispersed in rural areas.

CONCLUSIONS

In an adult population of patients attending an outpatient respiratory clinic in Hamilton, living close to major roadways was associated with an increased risk of moderate airway hyper-responsiveness. This correlation suggests that exposure to traffic emissions may provoke the pathology of airway hyper-responsiveness leading to variable airflow obstruction.

Effect of maternal exposure to ozone on reproductive outcome and immune, inflammatory, and allergic responses in the offspring

There is growing concern that exposure to air pollutants during pregnancy affects health outcomes in the offspring due to alterations in the development of immune and other homeostatic processes. To assess the risks of maternal inhalation exposure to ozone (O(3)), timed pregnant BALB/c mice were exposed to different concentrations of O(3) (0, 0.4, 0.8, and 1.2 ppm) for 4 h/day for 10 days during gestation (GD9-GD18), and pulmonary inflammation and immune responses were assessed in the offspring at 6 weeks-of-age. Maternal O(3) exposure reduced the number of productive dams by 25% at the highest O(3) concentration (1.2 ppm) and decreased the rate of weight gain in the offspring. Delayed-type hypersensitivity responses to bovine serum albumin were suppressed in the female offspring by maternal exposure to the two highest concentrations of O(3), whereas humoral immune responses to sheep red blood cells were not altered in either sex. Maternal exposure to 1.2 ppm O(3) increased lactate dehydrogenase (LDH) activity in bronchoalveolar lavage fluid (BALF) of the offspring but did not affect the number of inflammatory cells or levels of total protein, IFN-γ, IL-17, and IL-4 cytokines in BALF, or CD4(+), CD8(+), CD25(+), and TCRβ(+)CD1d(+) T-cells in the spleen. Offspring born from air-exposed dams sensitized early in life (postnatal day [PND] 3) to ovalbumin (OVA) antigen and then challenged as adults developed eosinophilia, elevated levels of LDH activity and total protein in BALF, and increased pulmonary responsiveness to methacholine, compared with animals sensitized at PND42. Maternal O(3) exposure in the 1.2 ppm O(3) group decreased BALF eosinophilia and serum OVA-specific IgE in the female offspring sensitized early in life but did not affect development of allergic airway inflammation by offspring sensitized late in life. In summary, maternal exposure to O(3) affected reproductive outcome and produced modest decreases in immune function and indicators of allergic lung disease in surviving offspring.

Exposure to traffic: lung function and health status in adults with asthma

BACKGROUND

Exposure to traffic has been associated with asthma outcomes in children, but its effect on asthma in adults has not been well studied.

OBJECTIVE

To test the hypothesis that lung function and health status are associated with traffic exposures.

METHODS

We measured FEV(1) % predicted, general health status using the Physical Component Scale of the 12-item Short Form (SF-12 PCS), and quality of life (QoL) using the Marks Asthma Quality of Life questionnaire in a cohort of adults with asthma or rhinitis (n = 176; 145 with asthma). We assessed exposures to traffic by geocoding subjects' residential addresses and assigning distance to roadways. Associations between distance to nearest roadway and distance to nearest major roadway and FEV(1) % predicted or SF-12 PCS were studied by using linear regression.

RESULTS

FEV(1) % predicted was positively associated with distance from both nearest roadway (P = .01) and nearest major roadway (P = .02). SF-12 PCS and QoL were not significantly associated with either traffic variable. Adjustment for income, smoking, and obesity did not substantively change the associations of the traffic variables with FEV(1) % predicted (P = .04 for nearest roadway and P = .02 for nearest major roadway) and did not cause associations with either SF-12 PCS or QoL to become significant.

CONCLUSIONS

Traffic exposure was associated with decreased lung function in adults with asthma.

Traffic, outdoor air pollution, and asthma

The epidemiology of asthma and outdoor air pollution has shown that respiratory health effects can vary in relation to different emission sources, types of pollutants, underlying nutritional status, medication use, and genetic polymorphisms. Using sophisticated exposure assessment methods in conjunction with clinical tests and biomarkers that provide mechanistic information, the study of outdoor epidemiology and asthma has evolved into a complex multidisciplinary field. This article presents an overview of the mechanisms by which outdoor air pollution and traffic-related emissions lead to changes in respiratory health and lung function in subjects with asthma.

Increased transcription of immune and metabolic pathways in naive and allergic mice exposed to diesel exhaust

Diesel exhaust (DE) has been shown to enhance allergic sensitization in animals following high-dose instillation or chronic inhalation exposure scenarios. The purpose of this study was to determine if short-term exposures to diluted DE enhance allergic immune responses to antigen, and identify possible mechanisms using microarray technology. BALB/c mice were exposed to filtered air or diluted DE to yield particle concentrations of 500 or 2000 mug/m(3) 4 h/day on days 0-4. Mice were immunized intranasally with ovalbumin (OVA) antigen or saline on days 0-2, challenged on day 18 with OVA or saline, and all mice were challenged with OVA on day 28. Mice were necropsied either 4 h after the last DE exposure on day 4, or 18, 48, and 96 h after the last challenge. Immunological endpoints included OVA-specific serum IgE, biochemical and cellular profiles of bronchoalveolar lavage (BAL), and cytokine production in the BAL. OVA-immunized mice exposed to both concentrations of DE had increased eosinophils, neutrophils, lymphocytes, and interleukin-6 (high dose only) post-challenge compared with OVA control, whereas DE/saline exposure yielded increases in neutrophils at the high dose only. Transcriptional microarray analysis 4 h after the last DE exposure demonstrated distinct gene expression profiles for the high-dose DE/OVA and DE/saline groups. DE/OVA induced oxidative stress and metabolism pathways, whereas DE in the absence of immunization modulated cell cycle control, growth and differentiation, G-proteins, and cell adhesion pathways. This study shows for the first time early changes in gene expression induced by the combination of DE inhalation and mucosal immunization, which resulted in stronger development of allergic eosinophilia.

Traffic-related Exposures, Airway Function, Inflammation, and Respiratory Symptoms in Children

RATIONALE

Traffic-related emissions have been associated with respiratory symptoms in some studies. However, there is limited information on how traffic-related emissions relate to lung function and airway inflammation.

OBJECTIVES

To determine the differential association of traffic-related exposures with exhaled nitric oxide (NO) and lung volumes and symptoms in children with and without asthma.

METHODS

We performed a longitudinal study of 200 children from ages 6 to 12 years of whom half had physician-diagnosed asthma. Two-week NO(2) and 48-hour average levels of elemental carbon and particulate matter of less than 2.5 microm (PM(2.5)) were measured at participating schools. Road and traffic densities were determined at schools and at each participant's house.

MEASUREMENTS AND MAIN RESULTS

In children with asthma, an interquartile increase in road density within the 50-, 100-, and 200-m home buffer areas was associated with increased exhaled NO (50 m: 28%; P = 0.03; 95% confidence interval [CI], 3-60; 100 m: 27%; P = 0.005; 95% CI, 8-49; 200 m: 17%, P = 0.09, 95% CI, -2 to 40), and reduced FEV(1) (50 m: -0.091 L; P = 0.038; 95% CI, -0.174 to -0.007; 100 m: -0.072 L, P = -0.028, 95% CI, -0.134 to -0.009; 200 m: -0.106 L, P = 0.002, 95% CI, -0.171 to -0.041]). Exposure to NO(2) at schools was marginally associated with reduced FEV(1) (-0.020; P = 0.060; 95% CI, -0.042 to 0.001). We did not observe significant associations with PM(2.5) or elemental carbon on exhaled NO. We did not observe significant reductions in lung volumes or changes in exhaled NO among healthy children.

CONCLUSIONS

Vehicular traffic exposures are associated with increased levels of exhaled NO and reduced lung volumes in children with asthma.

Concentrations of vehicle-related air pollutants in an urban parking garage

There is growing evidence that traffic-related air pollution poses a public health threat, yet the dynamics of human exposure are not well understood. The urban parking garage is a microenvironment that is of concern but has not been characterized. Using time-resolved measurement methods, we evaluated air toxics levels within an urban parking garage and assessed the influence of vehicle activity and type on their levels. Carbon monoxide (CO) and particle-bound polycyclic aromatic hydrocarbons (pPAH) were measured with direct-reading instruments. Volatile organic compounds (VOCs) were measured in 30 min intervals using a sorbent tube loaded sequential sampler. Vehicle volume and type were evaluated by video recording. Sampling was conducted from June 24 to July 17, 2002. We observed garage traffic median volumes of 71 counts/h on weekdays and 6 counts/h on weekends. The 12-fold reduction in traffic volume from weekday to weekend corresponded with a decrease in median air pollution that varied from a minimum 2- (CO) to a maximum 7 (pPAH)-fold. The actual 30-min median weekday and weekend values were: CO--2.6/1.2 ppm; pPAH--19/2.6 ng/m(3); 1,3-butadiene-0.5/0.2 microg/m(3), MTBE-7.4/0.4 microg/m(3); and benzene-2.7/0.3 microg/m(3). The influence of traffic was quantified using longitudinal models. The pollutant coefficients provide an indication of the average air pollution vehicle source contribution and ranged from 0.31 (CO) to 1.08 (pPAH) percent increase/vehicle count. For some pollutants, a slightly higher (0.5-0.6%) coefficient was observed for light-trucks relative to cars. This study has public health relevance in providing a unique assessment of air pollution levels and source contribution for the urban parking garage.

Geographic variations of childhood asthma hospitalization and outpatient visits and proximity to ambient pollution sources at a U.S.-Canada border crossing

BACKGROUND

Childhood asthma is a significant public health problem in the United States and evidence is accumulating regarding the contribution from traffic and ambient air pollution. This study is a companion piece of a related Buffalo asthma study in adults recently published in the July 2004 issue of American Journal of Public Health. This study focuses on children under 18 years of age diagnosed with asthma during a three-year period (2000-2002). In order to determine the effects of particulate air pollution on public health, we conducted an ecologic study of childhood asthma and point-source respirable particulate air pollution in patients diagnosed with asthma (n = 6,425). Patients diagnosed with gastroenteritis (n = 5,132) were used as controls.

RESULTS

Although the results of this study show spatial patterns similar to the ones observed in the adult study, a multiple-comparison test shows that EPA-designated focus sites located in Buffalo's east side are statistically (p < 0.008) more linked to childhood asthma than sites located elsewhere.

CONCLUSION

Findings of this study can be useful in geographic targeting and in the design of optimal and preventive measures.

Geographic clustering of adult asthma hospitalization and residential exposure to pollution at a United States-Canada border crossing

OBJECTIVES

We conducted a case-control study of adulthood asthma and point-source respirable particulate air pollution with asthma-diagnosed case patients (n = 3717) and gastroenteritis-diagnosed control patients (n = 4129) to determine effects of particulate air pollution on public health.

METHODS

We used hospitalization data from Buffalo, NY, neighborhoods for a 5-year period (1996 through 2000), geographic information systems techniques, the Diggle method, and statistical analysis to compare the locations of case patients and control patients in terms of proximity to different known pollution sources in the study area.

RESULTS

We found a clustering of asthma cases in close proximity to the Peace Bridge Complex and the freeways and a dose-response relationship indicating a decreased risk of asthma prevalence the farther an individual resides from the source of exposure.

CONCLUSIONS

These findings provide a basis for the development of new hypotheses relating to the spatial distribution of asthma prevalence and morbidity in this community.