Evaluation of VOC concentrations in indoor and outdoor microenvironments at near-road schools.

A 14-week air quality study, characterizing the indoor and outdoor concentrations of 18 VOCs at four El Paso, Texas elementary schools, was conducted in Spring 2010. Three schools were in an area of high traffic density and the fourth school, considered as a background school, was situated in an area affected minimally by stationary and mobile sources of air pollution. Passive samplers were deployed for monitoring and analyzed by GC/MS.

Evaluation of Sources and Patterns of Elemental Composition of PM at Three Low-Income Neighborhood Schools and Residences in Quito, Ecuador.

Elemental characterization of fine particulate matter was undertaken at schools and residences in three low income neighborhoods in Quito, Ecuador. The three zones were located in the northern (Cotocollao), south central (El Camal), and south east (Los Chillos) neighborhoods and were classified as zones 1-3, respectively. Forty elements were quantified via ICP-MS analysis.

Assessment of indoor and outdoor PM species at schools and residences in a high-altitude Ecuadorian urban center.

An air monitoring campaign to assess children's environmental exposures in schools and residences, both indoors and outdoors, was conducted in 2010 in three low-income neighborhoods in Z1 (north), Z2 (central), and Z3 (southeast) zones of Quito, Ecuador - a major urban center of 2.2 million inhabitants situated 2850 m above sea level in a narrow mountainous basin. Z1 zone, located in northern Quito, historically experienced emissions from quarries and moderate traffic.

Residential exposure to urban traffic is associated with increased carotid intima-media thickness in children.

Chronic exposure to urban traffic pollution is documented to promote atherosclerosis in adults but little is known about its potential effects in children. Our study examined the association of long-term exposure to traffic with carotid intima-media thickness (cIMT) in 287 healthy children. Residential proximity and distance-weighted traffic density (DWTD) were used as proximity markers for traffic-related air pollution exposure.

Ultrafine particle levels at an international port of entry between the US and Mexico: exposure implications for users, workers, and neighbors.

Exposure to diesel-emitted particles has been linked to increased cancer risk and cardiopulmonary diseases. Because of their size (<100 nm), exposure to ultrafine particles (UFPs) emitted from heavy-duty diesel vehicles (HDDV) might result in greater health risks than those associated with larger particles. Seasonal UFP levels at the International Bridge of the Americas, which connects the US and Mexico and has high HDDV traffic demands, were characterized.

Associations between urban air pollution and pediatric asthma control in El Paso, Texas.

Exposure to traffic-related pollutants poses a serious health threat to residents of major urban centers around the world. In El Paso, Texas, this problem is exacerbated by the region's arid weather, frequent temperature inversions, heavy border traffic, and an aged, poorly maintained vehicle fleet. The impact of exposure to traffic pollution, particularly on children with asthma, is poorly understood.

The effect of ventilation, age, and asthmatic condition on ultrafine particle deposition in children.

Ultrafine particles (UFPs) contribute to health risks associated with air pollution, especially respiratory disease in children. Nonetheless, experimental data on UFP deposition in asthmatic children has been minimal. In this study, the effect of ventilation, developing respiratory physiology, and asthmatic condition on the deposition efficiency of ultrafine particles in children was explored.

Evaluation of land use regression models for NO2 in El Paso, Texas, USA.

Developing suitable exposure estimates for air pollution health studies is problematic due to spatial and temporal variation in concentrations and often limited monitoring data. Though land use regression models (LURs) are often used for this purpose, their applicability to later periods of time, larger geographic areas, and seasonal variation is largely untested. We evaluate a series of mixed model LURs to describe the spatial-temporal gradients of NO(2) across El Paso County, Texas based on measurements collected during cool and warm seasons in 2006-2007 (2006-7).

Principal component analysis optimization of a PM2.5 land use regression model with small monitoring network.

The use of land-use regression (LUR) techniques for modeling small-scale variations of intraurban air pollution has been increasing in the last decade. The most appealing feature of LUR techniques is the economical monitoring requirements. In this study, principal component analysis (PCA) was employed to optimize an LUR model for PM2.

Air pollution and acute respiratory response in a panel of asthmatic children along the U.S.-Mexico border.

Background: Concerns regarding the health impact of urban air pollution on asthmatic children are pronounced along the U.S.-Mexico border because of rapid population growth near busy border highways and roads.

Binational school-based monitoring of traffic-related air pollutants in El Paso, Texas (USA) and Ciudad Juárez, Chihuahua (México).

Paired indoor and outdoor concentrations of fine and coarse particulate matter (PM), PM2.5 reflectance [black carbon(BC)], and nitrogen dioxide (NO(2)) were determined for sixteen weeks in 2008 at four elementary schools (two in high and two in low traffic density zones) in a U.S.

Using a continuous time lag to determine the associations between ambient PM2.5 hourly levels and daily mortality.

The authors are interested in understanding the possible association between exposure to short-term fine particulate matter (PM2.5) peaks that have changing physical characteristics throughout the day and observable health outcomes (daily mortality). To this end, modern statistical methods are used here that allow for a continuous time lag between hourly PM2.

Temporal-spatial analysis of U.S.-Mexico border environmental fine and coarse PM air sample extract activity in human bronchial epithelial cells.

Particulate matter less than 10 microm (PM10) has been shown to be associated with aggravation of asthma and respiratory and cardiopulmonary morbidity. There is also great interest in the potential health effects of PM2.5.

Determination of PM2.5 sources using time-resolved integrated source and receptor models.

Multivariate statistical techniques are applied to particulate matter (PM) and meteorological data to identify the sources responsible for evening PM spikes at Sunland Park, NM (USA). The statistical techniques applied are principal components analysis (PCA), redundancy analysis (RDA), and absolute principal components scores analysis (APCSA), and the data evaluated are 3-h average (6-9 p.m.

An innovative methodology for analyzing digital visibility images in an urban environment.

A novel methodology combining digital imaging, conventional fixed visibility monitors, and solar radiation monitors has been developed to characterize the visual air quality of the El Paso and Ciudad Juarez urban vista. The authors have found that the digital image quality is reproducible and useful for quantitative analysis of visibility conditions. Regions of interest were selected in images along view paths of interest and values for a contrast variable of interest, typically the coefficient of variation or contrast ratio (CR) for discrete targets, were computed.

PM source identification at Sunland Park, New Mexico, using a simple heuristic meteorological and chemical analysis.

The causes for evening low-wind PM10 and PM2.5 peaks at Sunland Park, NM, were investigated by using wind sector analysis and by assessing relationships between PM loadings and meteorological parameters through canonical ordination analysis. Both PM10 and PM2.

Characterization and implication of potential fugitive dust sources in the Paso del Norte region.

A series of analyses were performed to provide chemical signatures for surface soils and to evaluate potential sources of fugitive dust in the Paso del Norte (PdN) region. Eighteen sites were selected for soil sampling based on an assessment of the soil types in the region and the main upwind source areas with a potential for wind erosion. Analyses of the soil samples provided chemical 'fingerprints' of the surface soil that are presumed responsible for much of the fugitive dust loading in the region.

Aryl hydrocarbon receptor-mediated activity of particulate organic matter from the Paso del Norte airshed along the U.S.-Mexico border.

In this study, we determined the biologic activity of dichloromethane-extracted particulate matter < 10 micro m in aerodynamic diameter (PM10) obtained from filters at three sites in the Paso del Norte airshed, which includes El Paso, Texas, USA; Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, USA. The extracts were rich in polycyclic aromatic hydrocarbons (PAHs) and had significant biologic activity, measured using two in vitro assay systems: ethoxyresorufin-(O-deethylase (EROD) induction and the aryl hydrocarbon-receptor luciferase reporter system. In most cases, both EROD (5.