Evaluation of VOC concentrations in indoor and outdoor microenvironments at near-road schools. (December 2017)

• Record Type: Journal Article
• Authors: Raysoni, Amit U.; Stock, Thomas H.; Sarnat, Jeremy A.; Chavez, Mayra C.; Sarnat, Stefanie Ebelt; Montoya, Teresa; Holguin, Fernando; Li, Wen-Whai
• Is Part Of: Environmental pollution. Volume 231:Part 1(2017)
• Page Start: 681
• Page End: 693
• Publication Date: 2017-12
• Subjects: Air quality monitoring -- VOCs -- BTEX -- Schools -- Passive samplers; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2017.08.065
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: 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. Differences in the concentration profiles of the BTEX species between the high and low traffic density schools confirmed the pre-defined exposure patterns. Toluene was the predominant compound within the BTEX group and the 96-hr average outdoor concentrations varied from 1.16 to 4.25 μg/m 3 across the four schools. Outdoor BTEX species were strongly correlated with each other (0.63 < r < 1.00, p < 0.05) suggesting a common source: vehicular traffic emissions. As expected, the strength of the associations between these compounds was more intense at each of the three high-exposure schools in contrast to the low-exposure school. This was further corroborated by the results obtained from the BTEX inter-species ratios (toluene: benzene and m, p - xylenes: ethylbenzene). Certain episodic events during the study period resulted in very elevated concentrations of some VOCs such as n -pentane. Indoor concentration of compounds with known indoor sources such as α –pinene, d -limonene, p -dichlorobenzene, and chloroform were generally higher than their corresponding outdoor concentrations. Cleaning agents, furniture polishes, materials used in arts and crafts activities, hot-water usage, and deodorizing cakes used in urinal pots were the likely major sources for these high indoor concentrations. Finally, retrospective assessment of average ambient BTEX concentrations over the last twenty years suggest a gradual decrement in this border region. Graphical abstract: Highlights: Concurrent indoor and outdoor monitoring of 18 VOCs at four schools in El Paso. Strong correlations between BTEX species suggest traffic emissions as a major source. Toluene is the predominant compound in the BTEX group. Cleaning and deodorizing agents are major indoor sources of α –pinene, d -limonene. Abstract : This study characterizes the indoor and outdoor concentrations of Volatile Organic Compounds (VOCs) at four schools in El Paso, Texas, USA. Three schools were in a high traffic density (high exposure) zone and one school was located in a low traffic density zone (background school). VOC concentrations varied across the four schools, in both the microenvironments due to traffic emissions and other indoor sources.