Academic journal article Journal of Environmental Health

Formaldehyde Levels in Traditional and Portable Classrooms: A Pilot Investigation

Academic journal article Journal of Environmental Health

Formaldehyde Levels in Traditional and Portable Classrooms: A Pilot Investigation

Article excerpt

Introduction

During 1985-2008, public school enrollment increased from 39.4 million to 49.8 million in the U.S. (National Center for Educational Statistics [NCES], 2008), which led to overcrowding in some schools districts. A common response to overcrowding is to install temporary structures such as modular or portable buildings for use as classrooms. An estimated 33% (26,700 of 80,910) schools reported the use of portable classrooms (PCs) in 2005. Over 350,000 PCs are used throughout the U.S. (NCES, 2007).

Typical materials for building and furnishing PCs and new or modernized traditional school buildings may off-gas formaldehyde and other volatile organic compounds (VOCs) and result in exposures of public health concern (Hodgson, Shendell, Fisk, & Apte, 2004). Formaldehyde levels vary with type of construction materials, presence of pressed wood products, type of carpeting and flooring material, and efficiency of heating, ventilating, and air conditioning (HVAC) systems. The release of formaldehyde from pressed wood products and other sources is known to decrease over time (Meyer, 1979). Studies consistently show that highest indoor formaldehyde concentrations occur in new mobile homes and buildings, with values decreasing gradually over time (Hanrahan, Dally, Anderson, Kanarek, & Rankin, 1984; Norsted, Kozinetz, & Annegers, 1985; Sexton, Petreas, & Liu, 1989). Additionally, formaldehyde emissions from indoor sources, such as plywood and particle board, increase with temperature and relative humidity, being highest in the summer months (Meyer, 1979).

Children have greater susceptibility than adults to some environmental pollutants including formaldehyde because they breathe higher volumes of air relative to their body weights and have actively growing tissues and organs (Faustman, Silbernagel, Fenske, Burbacher, & Ponce, 2000). Acute exposure to formaldehyde can result in irritation of the throat, nose, eyes, and skin (Agency for Toxic Substances and Disease Registry [ATSDR], 2010). Several observational studies have demonstrated associations between formaldehyde and asthma outcomes, such as increased bronchial responsiveness in children with asthma, emergency treatment for asthma, increased risk of IgE-mediated sensitization, and increased diagnoses of asthma (ATSDR, 2010). Indoor exposure to formaldehyde has also been associated with chronic respiratory symptoms and decreased pulmonary function among children (Krzyzanowski, Quackenboss, & Lebowitz, 1990). Nasal irritation, eye irritation, and increased risk of asthma and allergies have been observed at airborne formaldehyde levels at 0.01-0.5 parts per million (ppm). Continuous exposure to formaldehyde also has led to increased IgE-mediated sensitization and symptoms at levels greater than 0.05 ppm, the World Health Organization's threshold, among primary schoolchildren (Wantke, Demmer, Tappler, Gotz, & Jarisch, 1996). Formaldehyde is also a human carcinogen (National Toxicology Program, 2013).

Few published studies have examined formaldehyde levels in occupied PCs, mainly from California (California Air Resources Board [CARB], 2003; Hodgson et al., 2004; Shendell et al., 2004; Shendell, Winer, Weker, & Colome, 2004a). Public health concerns about formaldehyde exposure during travel trailer and mobile home use following the Gulf Coast Hurricane Katrina in 2005 prompted this investigation (Centers for Disease Control and Prevention [CDC], 2008). Our primary objective was to describe formaldehyde levels in PCs and traditional classrooms (TCs) occupied by school-aged children, a potentially sensitive population. Secondary objectives were 1) to develop and field test a noninvasive, nonintrusive, and nondisruptive sampling protocol to measure levels of formaldehyde during school hours and overnight; and 2) to explore factors that may influence indoor air quality, such as use of HVAC systems, levels of carbon dioxide, temperature, and relative humidity. …

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