Asbestos Fiber Release Associated with Room Humidifiers

Abstract

Abstract A study was carried out to determine if portable room humidifiers (nebulizing or evaporative types) could aerosolize asbestos fibers from contaminated water. Deionized water seeded with chrysotile fibers obtained from a commercial source (23×106 fibers/L) was added to the humidifiers, which were run for 1 hour in a previously purged, 17-m3, unventilated room. Approximately 3000 L of air from each trial were collected by Gilian Aircon 520 high volume samplers. Simultaneous total particle counts were obtained using a Climet particle counter. Samples were examined by both phase contrast microscopy (PCM) and transmission electron (TEM) microscopy. The evaporative humidifiers did not emit asbestos fibers (≥5 μm in length) detectable by either PCM or TEM. From the nebulizing humidifiers, TEM (but not PCM) detected an average of 5.3 fibers (≥5 μm) per 10 grid squares corresponding to approximately 0.01 fiber/cc of air (range 0.0077-0.0140). Results provide evidence that asbestos fibers can be emitted by...