The effects of cracks and holes on the exhalation of radon from concrete have been investigated. It was found that the total radon exhaled from concrete blocks was the same irrespective of the diameters of holes drilled into them, and irrespective of the number of holes drilled. Furthermore, the surface area of the concrete blocks did not have any effect on the total radon exhaled

The primary objective of this study was to evaluate the effectiveness of different commercially available portable indoor air cleaning technologies in removing dust particulates from the indoor air. Suspended respirable particles are of great concern and often identified as important source of indoor air quality problems. The concentrations of particulate and gaseous pollutants encountered in the indoor environment frequently exceed those found outdoors by factor ranging from 2 to 20.