Exposure to Traffic-related Particles and Endotoxin during Infancy Is Associated with Wheezing at Age 3 Years

Abstract

Rationale: Murine models demonstrate a synergistic production of reactive oxygen species on coexposure to diesel exhaust particles and endotoxin. Objectives: It was hypothesized that coexposure to traffic-related particles and endotoxin would have an additive effect on persistent wheezing during early childhood. Methods: Persistent wheezing at age 36 months was assessed in the Cincinnati Childhood Allergy and Air Pollution Study, a high-risk birth cohort. A time-weighted average exposure to traffic-related particles was determined by applying a land-use regression model to the homes, day cares, and other locations where children spent time from birth through age 36 months. Indoor levels of endotoxin were measured from dust samples collected before age 12 months. The relationship between dichotomized (,/>75th percentile) trafficrelated particle and endotoxin exposure and persistent wheezing, controlling for potential covariates, was examined. Measurements and Main Results: Persistent wheezing at age 36 months was significantly associated with exposure to increased levels of traffic-related particles before age 12 months (OR 5 1.75; 95% confidence interval, 1.07-2.87). Coexposure to endotoxin had a synergistic effect with traffic exposure on persistent wheeze (OR 5 5.85; 95% confidence interval, 1.89-18.13) after adjustment for significant covariates. Conclusions:The association between traffic-related particle exposure and persistent wheezing at age 36 months is modified by exposure to endotoxin. This finding supports prior toxicological studies demonstrating a synergistic production of reactive oxygen species after coexposure to diesel exhaust particles and endotoxin. The effect of early versus later exposure to traffic-related particles, however, remains to be studied because of the high correlation between exposure throughout the first 3 years of life.

Fungi diversity in PM<sub>2. 5</sub> and PM<sub>1</sub> at the summit of Mt. Tai: abundance, size distribution, and seasonal variation

“…11248 C. Xu et al: Fungi Diversity in PM 2.5 and PM 1 at the summit of Mt. Tai ris et al, 2002;Yadav et al, 2004;Bowers et al, 2012Bowers et al, , 2013Cao et al, 2014;Ryan et al, 2009). Despite their importance, the abundance, diversity, and community structure of fungi associated with PM have received limited attention in terms of research.…”

Seasonal and Diurnal Variations of Fluorescent Bioaerosol Concentration and Size Distribution in the Urban Environment

“…Potential health risks of bioaerosols are especially high in urban environments due to their dense populations. Ryan et al (2009) reported that a combination of bioaerosols and traffic-related emission exposure was associated with wheezing at age 3 years. Bowers et al (2011) reported that the major bacteria sources in the urban environments are soil, leaf surfaces and dog feces.…”

Traffic Particles in Ambient Air of a Major US Urban Area: Has Anything Changed over a Decade?

“…Among them, there is the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) -a prospective birth cohort investigation (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) designed to determine if exposure to high levels of diesel exhaust particles (DEP) during early childhood increases the risk for developing allergic diseases. Resulting from the CCAAPS, wheezing, night cough and allergic rhinitis in infants residing in proximity to major roads and stop-and-go traffic was linked to exposure to elemental carbon attributable to traffic, which served as a marker for diesel exhaust particles (DEP) (Ryan et al, 2005(Ryan et al, , 2007(Ryan et al, , 2009Sucharew et al, 2010). Similar to other studies, CCAAPS relied on the aerosol exposure data measured in the tested metropolitan area over a specific period of time (beginning with the pilot study in 2001 and extending into a full-scale sampling in [2002][2003][2004][2005].…”

“…While OC is produced by all combustion sources, EC is primarily generated by traffic sources, largely by diesel-powered vehicles (Birch and Cary, 1996). As such, EC is frequently used as a surrogate for traffic generated aerosols (Holguin, 2008;Ryan et al, 2009;Hochstetler et al, 2011). The EC concentration and its contribution to PM 2.5 are greater in areas near highways and both increase with increased truck traffic (Kinney et al, 2000;Lena et al, 2002;Martuzevicius et al, 2004).…”