Evidence of inadequate ventilation in portable classrooms: results of a pilot study in Los Angeles County

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.     

Evaluation of drainage system around a lined pilot cavern for underground cryogenic LNG storage

A lined pilot cavern for underground cryogenic LNG (liquefied natural gas) storage was constructed in granite in Daejeon, Korea in 2003 and commissioned in 2004. As the hydrostatic pressure of groundwater and thermal stress due to the formation of ice lenses may damage the containment system, rock drainage around the pilot cavern is needed to maintain the stability of the containment system. Once the drainage works were completed, the level of groundwater around the pilot cavern was controlled using drainage holes to form an ice ring as a second barrier to prevent the leakage of LNG from the cavern. In order to establish the drainage system for the pilot cavern, 15 boreholes were drilled into the rock. Fractures in the rock mass around the pilot cavern were characterized to determine the most appropriate orientation for the drainage holes. The major joints acting as conduits for inflow water were designed for efficient drainage. After the 15 drainage holes were drilled and their efficiency tested during the dry season in April 2003, it was found that there was a problem with the inflow of water through the main joint along the right-hand wall of the cavern, indicating the system was less efficient on the right-hand side. Hence, three more boreholes were drilled in the correct direction on the right-hand wall of the cavern. A second drainage test was conducted during the rainy season in August. This showed some seepage into the bottom of the pilot cavern. In order to reduce this seepage, two more additional drainage holes were drilled and grouted below the concrete invert. Although the drainage system was very efficient, weak points in the system were found by testing and changes were made to the system to improve its efficiency.     

Window blind occlusion: a pilot study

Estimations of daylight factors, used to calculate energy savings, typically do not consider occupants' use of window blinds. The data indicate that such estimations should include some assessment of window blind usage, because over half of the window area is usually occluded in some way by blinds. It appears that many occupants purposely use window blinds to prevent sunlight from penetrating their working space.     

Public awareness of renewable energy: a pilot study

The paper briefly describes the proposals for tidal power generators for the river Severn UK and goes on to document the results of a pilot study carried out during 1982 to assess the attitude of local residents to the proposals and to various renewable energy conversion techniques. The research used interviews and group discussions as a means of determining attitudes to a series of photographs of appropriate equipment and situations. The photographs used are reproduced as part of the paper.     

Zinc protoporphyrin levels in children in Haifa: a pilot study

Zinc protoporphyrin (ZPP) levels of greater than or equal to 40 micrograms dl-1 were found in blood samples of 32 (12.1%) out of 264 children living in Kiryat Yam, Haifa Bay (a sea-level neighborhood with much vehicular traffic, located 4.5 km from an industrial zone in the bay area), 22 (8.8%) out of 251 children living in Neve Shaanan (located on a mountainside, 3.5 km from an industrial zone and exposed to visible smoke pollution), and 14 (6.5%) out of 214 children from Mt Carmel (Ahuza), which is furthest from industry and where visible signs of pollution are seldom seen. Zinc protoporphyrin levels, low in non-anemic infants, were slightly higher in 1st graders from all three neighborhoods; higher levels were found in both 3rd and 6th graders from Kiryat Yam, but only in 6th graders from Neve Shaanan. The ZPP levels remained unchanged in older, Mt. Carmel children. Zinc protoporphyrin concentrations of greater than or equal to 40 micrograms dl-1 varied inversely with two indices of socio-economic status (parental ethnic origin and father's educational level). Blood lead levels of greater than or equal to 20 micrograms dl of blood were found in eight (13%) out of 62 children with ZPP levels greater than or equal to 40 micrograms dl-1, but in none (0%) of 14 children with ZPP levels greater than or equal to 40 micrograms dl-1. Three (60%) out of five children with ZPP levels greater than or equal to 50 micrograms dl-1 had Pb levels of greater than or equal to 20 micrograms dl-1. In Kiryat Yam, Pb(B) was higher in 31 children with ZPP greater than or equal to 40 micrograms dl-1 compared with 13 with ZPP less than 40 micrograms dl-1. The data on age-associated increases in ZPP in children suggest the possibility of an effect on red blood cell porphyrin metabolism, in some cases from cumulative low level lead exposures, and in others from iron deficiency, especially in poorer socio-economic groups. The findings call for further studies, both in the populations studied here, and elsewhere, to determine the role of lead toxicity and iron deficiency in children of all age groups, and the need for preventive action.     

Mercury in some commercial fish from Kuwait: a pilot study

We investigated the total mercury content in the muscles, liver and gonads of eight commercial fish from Kuwait. Mercury concentrations in the muscle of all the fish were below the action level of 1 microgram g-1 (wet weight) set by the United States Food and Drug Administration. However, large specimens of Epinephelus tauvina (Hamoor) and Lutjanus Coccineus (Hamrah) showed concentrations which were close to the action level. The relationship between mercury concentration and fish age and length was in the form of an exponential correlation (Y = aXb), in which concentration increases with an increase in fish age or length. Correlation coefficients obtained ranged between 0.65 and 0.86.     

Office worker preferences of electrochromic windows: a pilot study

Electrochromic (EC) windows for building applications are a major issue within the built environment scientist community. A building envelope equipped with electro-optical glasses makes it possible to improve both its energy performance and the visual environment of the occupants. EC windows act as active components which can modulate the solar light flux input in order to attain energy saving. They also provide a better visual environment and a sensible cut of glare phenomena.     

Italian multicentre study on microbial environmental contamination in dental clinics: a pilot study

The dental practice is associated with a high risk of infections, both for patients and healthcare operators, and the environment may play an important role in the transmission of infectious diseases. A microbiological environmental investigation was carried out in six dental clinics as a pilot study for a larger multicentre study that will be performed by the Italian SItI (Society of Hygiene, Preventive Medicine and Public Health) working group "Hygiene in Dentistry". Microbial contamination of water, air and surfaces was assessed in each clinic during the five working days of the week, before and during treatments. Air and surfaces were also examined at the end of the daily activity. A wide variation was found in microbial environmental contamination, both within the participating clinics and relative to the different sampling times. Microbial water contamination in Dental Unit Water Systems (DUWS) reached values of up to 26 × 10⁴ cfu/mL (colony forming units per millilitre). P. aeruginosa was found in 33% of the sampled DUWS and Legionella spp. in 50%. A significant decrease in the Total Viable Count (TVC) was recorded during the activity. Microbial air contamination showed the highest levels during dental treatments and tended to decrease at the end of the working activity (p < 0.05). Microbial buildup on surfaces increased significantly during the working hours. As these findings point out, research on microbial environmental contamination and the related risk factors in dental clinics should be expanded and should also be based on larger collections of data, in order to provide the essential knowledge aimed at targeted preventive interventions.     

Investigating a single sensor ability in the characterisation of drinkable water: a pilot study

Physical and chemical characterization of Bottled water is certified on the bottle‐label, which reports the analysis performed by a qualified laboratory. All these data can be suitable treated via multidimensional evaluation and the value of certain parameters against a specific threshold, can address some of these water samples to the treatment of specific medical issues or more in general for dietary options. These thresholds are often referred only to two or three of the listed parameters. In this work, a single voltammetric sensor has been used to characterize 14 different species of bottled water, after a calibration procedure with saline matrices. The sensor has the capability to discriminate among water samples with different dry residue and it is also able to predict the parameters reported on the bottle‐label with an acceptable resolution. Considering the portability of the device and its satisfactory repeatability, the sensor could perform a water quality characterisation, synthesizing bottle‐water characteristic in a reproducible and characteristic profile. The device, when fully integrated and calibrated, can support bottled water monitoring in different steps of the production‐distribution‐utilization chain by means of real‐time measurements.     

Failure analysis of a geomembrane lined reservoir embankment

This paper presents case study and failure analysis of an embankment enclosing a raw water reservoir at a coal-based thermal power plant. The embankments and the base of the reservoir were all lined with geomembrane. Major breaches occurred in the embankment separating two compartments of the reservoir (i.e., the partition embankment) approximately one year after the filling of one of the reservoirs. Seepage and slope stability analyses were carried out to detect the causes of failure. The post–failure field observations and results of stability analyses indicated that the use of a single layer geomembrane as the sole component of barrier layer was inadequate. Pipe drains provided at the base of the reservoir to intercept rising groundwater level acted as a flow pathway for water seeping from tears and punctures in geomembrane liner at the base of the reservoir. The design of internal drainage system for both the partition embankment and peripheral embankment (i.e., the embankments other than the partition embankment surrounding the reservoir) was insufficient. The remedial measures which could be adopted for geosynthetic lined reservoir and embankment were evaluated and presented in the paper. The study highlights the need to provide a secondary liner in form of clay or geosynthetic clay liner whenever a geomembrane is used as a barrier layer. In cases where use of single layer of geomembrane is unavoidable, seepage and safety analysis should be carried out with the assumption that it may leak. This is important when an adequate quality control in laying the geomembrane is lacking or the embankment facilities would continue to be operated at full head even after the design life of the geomembrane is exceeded.     

Monitoring and modelling of manually-controlled Venetian blinds in private offices: a pilot study

This study presents results from a window blind usage survey and field study that was conducted in California, USA during a period spanning from the vernal equinox to the winter solstice. A total of 113 office building occupants participated in the survey. Twenty-five occupants participated in the field study. In this study, 83 measurements of physical environmental conditions were cross-linked with participants' window blind controlling preferences. A total of 13 predictive window blind control bivariate and multivariate logistic models were derived. As hypothesised, the probability of a window blind closing event increased as the magnitude of physical environmental and confounding factors increased (p < 0.01). The main predictors were window/background luminance level and vertical solar radiation at the window. The confounding factors included MRT, direct solar penetration and participants' self-reported sensitivity to brightness. The results showed that the models correctly predict between 72–89% of the observed window blind control behaviour. This research extends the knowledge of how and why building occupants manually control window blinds in private offices, and provides results that can be directly implemented in energy simulation programs.     

Estimation of daily inhalation rate in preschool children using a tri-axial accelerometer: a pilot study

The activity of 5- to 6-year-old Japanese children (n = 29) was monitored for 3 consecutive days, including one weekend day, using an ActivTracer tri-axial accelerometer. The daily inhalation rate and time spent in sedentary, light, or moderate to vigorous levels of physical activity (MVPA) were estimated from the accelerometer measurements based on previously developed regression equations. The 3-day mean daily inhalation rate (STPD) was estimated at 8.3 ± 1.4 m³ day⁻¹ in 10 subjects who completed 3 days of monitoring. The time spent in sedentary, light, or MVPA each day was 320, 415, and 81 min day⁻¹, respectively. Analysis of between-day reliability indicated that 3 days of monitoring with the ActivTracer tri-axial accelerometer provided an acceptable estimate of daily inhalation rate (intra-class correlation coefficient [ICC] = 0.892), but low to moderate reliability for the time spent in different levels of activities (ICC = 0.43 to 0.58). We observed a significant difference in the daily inhalation rate between weekdays and the weekend day, possibly due to differences in time spent in MVPA. This finding suggests that a weekend day should be included to obtain more reliable estimates of daily inhalation rate using an accelerometer.     

The natural (baseline) quality of groundwater: a UK pilot study

Knowledge of the natural baseline quality of groundwaters is an essential prerequisite for understanding pollution and for imposing regulatory limits. The natural baseline of groundwaters may show a range of concentrations depending on aquifer mineralogy, facies changes, flow paths and residence time. The geochemical controls on natural concentrations are discussed and an approach to defining baseline concentrations using geochemical and statistical tools is proposed. The approach is illustrated using a flowline from the Chalk aquifer in Berkshire, UK where aerobic and anaerobic sections of the aquifer are separately considered. The baseline concentrations for some elements are close to atmospheric values whereas others evolve through time-dependent water-rock interaction. Certain solutes (K, NH(4)(+)), often considered contaminants, reach naturally high concentrations due to geochemical controls; transition metal concentrations are generally low, although their concentrations may be modified by redox controls. It is recommended that the baseline approach be incorporated into future management strategies, notably monitoring.     

Small-scale spatial variability of particle concentrations and traffic levels in Montreal: a pilot study

Little is known about the particulate exposure of populations living along major urban roads. The objective of this pilot study was to explore the small-scale spatial and temporal variability of the absorption coefficient of PM2.5 filters, as a surrogate for elemental carbon, in relation to levels of PM2.5, at residential sites with varying traffic densities in a large Canadian city. Concurrent 24-h measurements were performed at four residential sites during 7 weeks. A gradient existed across all four sites for the absorption coefficient of the filters (and NO2 levels). In contrast, the levels of PM2.5 were quite similar at all sites. The difference in the filter absorption coefficient of PM2.5 filters, between an urban background and a residential traffic site (with about 30000 vehicles/day), expressed as a percentage of the background site, was 40%. These results indicate that spatial variability in PM2.5 absorption coefficient can be observed with traffic intensity on a small scale within a North American city and suggests that regression modelling approaches similar to those used in European studies could be used to estimate exposure of the general population to traffic-related particles on a local scale in North America.     

Quantification of annular flow in lined pipelines

This paper attempts to quantify the amount of flow within the annular space that could exist between a polymeric liner and a deteriorated host pipe. Inadequate fit of the liner within sewer line segments is likely to cause annular flow that will result in a higher flow rate within the wastewater collection system. The results of full-scale field tests performed by the authors on 12 pipelines lined with four different deformed/reformed or fold-and-form (DR/FF) and cured-in-place-pipe (CIPP) liner products indicated that gaps of different sizes existed in all of the tested pipelines. These gaps have resulted in variable annular flow in the tested pipelines. Based on the results of the full-scale tests, a mathematical relationship was established between the annular flow in a lined pipeline and the annular space. The relationship between the annular flow rate and the average annular gap size depends on the difference in head between the entry and exit points along the pipeline. In turn, the average annular gap size depends on many factors including tolerances and imperfections in the host pipe and liner, conditions of the host pipe and the quality of liner installation. A third-order polynomial equation was found to best describe the relationship between the annular flow and average gap size under high differential heads (up to 3.0 m or 10 ft); whereas, a logarithmic relationship fits best under low differential heads for wider range of annular gap sizes (up to 17.8 mm or 0.70 in.). Based on the results of the full-scale tests, this is believed to be more representative of typical liner installations.     

Wastewater disinfection with PAA and UV combined treatment: a pilot plant study

This study is part of a larger research project on Advanced Treatments for wastewater reuse in agriculture. Because of Italy's strict microbiological limits on unrestricted wastewater reuse in agriculture (2 MPN/100ml Total Coliforms), a very high degree of disinfection is necessary.The objective of this study is to proceed in validating, with a pilot plant experimentation, previous laboratory results on the disinfection efficacy of the synergic combined treatment between ultraviolet irradiation (UV) and peracetic acid (PAA). The research has been carried out through a 5 month on-site experimental study in a pilot plant, considering four different solutions: PAA addition, UV irradiation, addition of PAA upstream the UV device (PAA+UV) and addition of PAA downstream the UV device (UV+PAA). In the investigated experimental conditions (2-8 ppm of PAA with 10-30 min contact time; 100-300 mJ/cm(2) UV), it has been impossible to meet the microbiological limits through an exclusive use of UV irradiation or PAA. The disinfection efficacy enhances by using the UV+PAA treatment, but a much higher efficacy gain occurs by using the PAA+UV treatment. In this latter case, the higher efficiency is recognized as being brought about by the formation of free radicals due to the photolysis of the PAA when in presence of the UV rays. A preliminary cost analysis has been carried out in order to highlight the more economically advantageous solution which guarantees compliance to the strict limits.     

Methanol exposure to car occupants from windshield washing fluid: a pilot study

Automobile occupants might be exposed to considerable amounts of methanol from previously unreported source, namely via the inhalation of vapors of winter-grade, methanol-based, windshield washing fluid that drains to the intake air ducts of the car. Air samples were collected in passenger cars during simulated operating conditions and analyzed for methanol via headspace gas chromatography-mass spectrometry, electron impact, selected ion monitoring. The method was linear in the 2-2000 ppm range. Concentrations exceeding 1000 ppm were recorded. PRACTICAL IMPLICATIONS: Using a winter-grade, methanol-based, windshield washing fluid for windshield cleaning in a passenger car can result in a methanol concentration in the air of the passenger cabin in excess of 1000 ppm. In view of the widespread use of this product, more studies are necessary to elucidate, in depth, the concentrations of methanol vapors which could be encountered in various weather and driving conditions as well as the concomitant contributing influences of car design. These studies are necessary to properly assess the hazards associated with use of the fluid and possible mitigation approaches which might include substitution of methanol by less toxic formulations.     

Evaluation and application of controlling parameters for seismic events in hard-rock mines

A method is proposed for quantitative assessment and interpretation of the seismic hazard of planned excavation in a hard-rock mine. The quantitative assessment is derived from three-dimensional, elastic, boundary element modelling of the host rock mass. Parameters obtained from the modelling are associated with historical observations of seismicity in the mine to generate probabilistic relations between seismic event occurrence and event strength. The parameters used in the event spatial occurrence relations and the event strength estimates are the Factor of Safety against seismic failure for different types of seismic events, which are inferred from back analysis of field observations, and the Modelled Ground Work. The estimates of these parameters are related to the controlling quantities for a seismic event, which are a local state of stress sufficient to cause rock mass failure, and an unstable local concentration of strain energy, i.e. energy in excess of that which can be dissipated non-violently in rock mass failure. Application of the method is illustrated by reference to several case studies of mine seismicity.     

Evaluating emergency management capability of a water utility: A pilot study using exercise metrics

There is a societal expectation that we will still have access to essential services in the immediate aftermath of a disaster. This necessitates that utility organisations are resilient and therefore prepared for unexpected threats. One important type of preparedness activity is exercising. This research note presents findings from a pilot study in which performance evaluation metrics were developed for an emergency management exercise conducted by a water utility. Initial findings suggest that metrics and benchmarks can be successfully applied in this domain with positive implications for planning and policy across the utilities sector.     

Heterotrophic activity compromises autotrophic nitrogen removal in membrane-aerated biofilms: results of a modeling study

A 1-d multi-population biofilm model was constructed to study the effect of heterotrophic activity on completely autotrophic ammonium (NH4+) removal in membrane-aerated (counter-diffusion) versus conventional biofilm systems (co-diffusion). Growth of heterotrophic bacteria (HB) was supported either solely by biomass decay products or by organic carbon (as chemical oxygen demand (COD)) in the influent. Three scenarios were considered: influence of HB growing on biomass decay products on steady-state performance (total nitrogen (TN) removal efficiency); influence of the influent COD/N ratio on steady-state performance (supplying COD in the influent); and impact of dynamic changes in the influent COD/N ratio on TN removal efficiency. The results revealed that the TN removal efficiency in the counter-diffusion biofilm was significantly different when HB were included in the simulations at NH4+ surface loads of LNH4>2.7 g - N m(-2) d(-1). Influent COD significantly altered the microbial community composition in the counter-diffusion biofilm and anaerobic NH4+ oxidation could not be sustained at COD/N>2. The co-diffusion system, however, was less affected and more than 50% of the TN removal originated from anaerobic NH4+ oxidation at those ratios. Perturbation experiments showed that step increases to influent COD/N ratios of 2 or higher over a period of 50 d or longer caused a loss of anaerobic NH4+ oxidation capacity which could not be regained within a reasonable time frame (>1000 d) in the counter-diffusion system. In contrast, simulating a 1-d sloughing event only caused a disturbance of 200 d although a maximum biofilm loss of 90-95% occurred. These results clearly indicate the importance of heterotrophic activity in autotrophic N removal biofilms, especially in counter-diffusion systems where they may compromise N removal capacity.