Evidence of inadequate ventilation in portable classrooms: results of a pilot

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Indoor Air

Volume 14 Issue 3 Page 154 - June 2004

doi:10.1111/j.1600-0668.2004.00235.x

Evidence of inadequate ventilation in portable classrooms: results

of a pilot study in Los Angeles County

D. G. Shendell1,2, A. M. Winer1, R. Weker3, S. D. Colome4

Abstract

The prevalence of prefabricated, portable classrooms (portables) for

United States public schools has increased; in California,

approximately one of three students learn inside portables. Limited

research has been conducted on indoor air and environmental quality

in American schools, and almost none in portables. Available reports

and conference proceedings suggest problems from insufficient

ventilation due to poor design, operation, and/or maintenance of

heating, ventilation and air conditioning (HVAC) systems; most

portables have one mechanical, wall-mounted HVAC system. A pilot

assessment was conducted in Los Angeles County, including

measurements of integrated ventilation rates based on a

perfluorocarbon tracer gas technique and continuous monitoring of

temperature (T) and relative humidity (RH). Measured ventilation

rates were low [mean school day integrated average 0.8 per hour

(range: 0.1-2.9 per hour)]. Compared with relevant standards,

results suggested adequate ventilation and associated conditioning

of indoor air for occupant comfort were not always provided to these

classrooms. Future school studies should include integrated and

continuous measurements of T, RH, and ventilation with appropriate

tracer gas methods, and other airflow measures.

Practical Implications

Adequate ventilation has the potential to mitigate concentrations of

chemical pollutants, particles, carbon dioxide, and odors in

portable and traditional classrooms, which should lead to a

reduction in reported health outcomes, e.g., symptoms of 'sick

building syndrome', allergies, asthma. Investigations of school

indoor air and environmental quality should include continuous

temperature and relative humidity data with inexpensive

instrumentation as indicators of thermal comfort, and techniques to

measure ventilation rates.