“…(43) An improved method for evaluating the penetration of protective clothing materials by toxic particles was presented. (44) Other investigators reported finding elevated levels of many hazardous air pollutants, using diffusive samplers, inside residential buildings, as compared to the corresponding outside concentration^. (^') Monitoring for respirable fibers in commercial buildings, with phase contrast microscopy and scanning electron microscopy with energy-dispersive X-ray microanalysis, indicated that fiber levels ranged up to 0.032 fibedcc, with almost all fibers being organic in content, as opposed to man-made vitreous fibers.…”