An indoor radon survey has been carried in 120 schools situated in four districts of the Punjab province, namely Attock, Chakwal, Jhelum, and Rawalpindi. In each season, a total of 360 CR-39-based radon detectors were installed in the selected schools. After exposure the detectors were etched in 6M NaOH at 80°C solution for 16 h and tracks densities, which are related to the radon concentration, were measured. Indoor radon concentration varied from 18 ± 7 to 168 ± 5 Bq·m^-3 with an average value of 52 ± 9 Bq·m^-3. High indoor radon concentration values were found in the summer season, whereas lower values were recorded in autumn season. The mean annual radon effective dose equivalent was estimated to be 0.49 mSv per year. Present indoor radon concentration values are higher than that of the world average value of 40 Bq·m^-3, but lower than the action level recommended by the ICRP.

The type of flooring in hospitals has long been scrutinized in terms of its potential role in nosocomial (hospital-acquired) infections. This study was conducted for the purpose of detecting potential pathogens on tiled carpets, nontiled carpets, and vinyl flooring, all used in a Midwestern community hospital. A swab sampling protocol conducted over a 5-month period, coupled with denaturing gradient gel electrophoresis-16S rDNA molecular analysis, allowed for greater than 93% of the major components in the flooring samples to be identified at the genus and species level. This study evaluates the impact of floor finish materials as potential sources of microbial-related hospital-acquired infections.

Two independent modifications were made to one of two identical side-by-side filter banks for a large air-handler: (1) new filter holders, intended to provide a better seal and (2) ultraviolet germicidal irradiation (UVGI) lamps, intended to control microbiological growth. Total system efficiency testing with optical particle counters was performed to determine the effectiveness of the new filter holders. The efficacy of the UVGI lamps was determined through biological surface and air sampling. Results indicated that the side with the new filter holders was about 3.4% more efficient per year during the 22-month sampling period, whereas the coil chamber with the UVGI lamps had less biological contamination than the corresponding control chamber for over 75% of the sampling days.

A detailed evaluation of 122 air samples collected in and around Libby, Montana and previously analyzed by EPA has been performed. Photographic records of each analyzed particle were collected and archived in a searchable database. The results of the study indicate that the EPA’s failure to follow generally accepted procedures overestimated the concentration of regulated asbestos fibers by 10 times and by 3 times for all asbestiform fibers. These results are applicable to the analysis of naturally occurring asbestos in all parts of the country. The results demonstrate the need for detailed morphological and chemical analyses to reliably determine potential exposures and associated risks when evaluating mixed asbestos/non-asbestos environments.

Amphibole asbestos fibers and non-asbestos amphibole particles have been shown to have different size characteristics, in addition to their morphological differences. There is a tendency, however, among laboratories and some regulators to ignore the morphological differences and to simply rely on a minimal aspect ratio to determine whether a particle is an asbestos fiber. This study, part of a larger evaluation of amphibole minerals, was undertaken to provide supporting size data that can be used to identify populations of asbestos and non-asbestos amphibole minerals. The asbestos samples average 0.27 µm in width with 90% thinner than 0.5 µm. In contrast, the non-asbestos amphiboles average 0.97 µm wide with 75% wider than 0.53 µm. The average aspect ratios were 76 : 1 for asbestos and 16 : 1 for the non-asbestos samples. These data confirm the historical distinctions of asbestos and non-asbestos amphibole minerals.

Advanced naturally ventilated systems based on integration of basic natural ventilation strategies such as cross-ventilation and stack effect have been considered to be a key element of sustainable design. In this respect, there is a pressing need to explore the potential of such systems to achieve the recommended occupant comfort targets throughout their lifetime without relying on mechanical means. This study focuses on use of a windcatcher system in typical classrooms which are usually characterized by high and intermittent internal heat gains. The aims of this paper are 3-fold. First, to describe a series of field measurements that investigated the ventilation rates, indoor air quality, and thermal comfort in a newly constructed school located at an urban site in London. Secondly, to investigate the effect of changing climate and occupancy patterns on thermal comfort in selected classrooms, while taking into account adaptive potential of this specific ventilation strategy. Thirdly, to assess performance of the ventilation system using the newly introduced performance-based ventilation standards for school buildings. The results suggest that satisfactory occupant comfort levels could be achieved until the 2050s by a combination of advanced ventilation control settings and informed occupant behavior.

The UK is undertaking a large-scale rebuilding of its school stock. The scale of the operation has meant that designers with little knowledge of school design are frequently involved. One negative consequence of this can be poor acoustic design and therefore a poor indoor environment. This paper is in part pedagogical, and presents a series of new key relationships in the acoustics of school spaces with an emphasis on dining rooms – an area with which architects have been found to have difficulties. Hopefully, this work will allow architects and building services engineers to appreciate better various salient points and to understand fully the flexibility they have to design novel spaces that can provide a high quality educational experience. Several novel equations are derived that acousticians, building services engineers, and architects may feel useful during the early stages of the design process. Three case studies are also given.

Six occupied single-family dwellings in Ottawa, Canada were subjected to weekly or bi-weekly professional cleaning using a HEPA filter-equipped vacuum cleaner and following a strict cleaning protocol based on floor area and type of floor. Sieved weights of dust were collected from each cleaning. Statistically significant reductions of fine dust loading occurred only after four sequential cleanings. As dust loading of the floor was reduced, exposure to dust mite allergens, endotoxins, and fungal glucans in dust decreased. During the first cleaning (when loadings were highest), airborne particles were collected using a MOUDI sampler (0.18–18 µm size fractions). The fungal polysaccharide β-(1, 3)-D-glucan was present in approximately equal proportions in each size fraction. This demonstrates that the majority of the fungal exposure was not to intact spores, but to fungal fragments much smaller than spores that have greater efficiency of deeper penetration into the lungs. This study also shows the importance of ensuring that cleaning interventions are effective before they can be related to health outcomes.

Hong Kong is one of the most densely populated cities in the world. Its buildings are largely high-rise blocks constructed close to each other and, hence outdoor obstructions play significant roles in daylighting designs. The light reflected from the ground and surrounding buildings can be important sources of interior lighting and detailed computations are required. We currently propose a calculation procedure in terms of a number of regression equations to determine the daylight illuminance on vertical surfaces. This paper presents the work to assess this approach via full-scale measurements under real sky conditions. The mean surface reflectance for external obstructions was estimated using lighting simulation techniques. It was shown that daylight illuminance obtained by the proposed method were in reasonably good agreement with measured readings. The simple nature of the proposed approach offers building professionals and students a reliable and convenient alternative to predict daylight illuminance particularly when different daylighting schemes and concepts are being considered.