- : # l 6 ooc 4405 Ventilation and Air Quality in Indoor Ice Skating Arenas
There are thousands of indoor ice rink arenas in the United States, Canada, and Europe. The combustion byproducts from the feel-powered ice resurfacing equipment are a potential health risk to both athletes and spectators. A field survey of ten ice rink arenas in Greater Boston and Halifax, Nova Scotia, indicates that the fael type used by the resurfacer as well as the air exchange rate, the air distribution method, and the operation strategy of the ventilation system are significant contributing factors to the indoor air quality (JAQ) . Computational fluid dynamics (CFD) has been used to systematically investigate the impact of the air exchange rate, air distribution method, and ventilation control strategies on the IAQ in an arena. With CFD, it is possible to develop design and operating guidelines for ventilation systems in order to reduce contamination levels in the arenas.
Task-Specific Ventilated Robotic Enclosures for Product and Worker Protection against Biological Hazards in High-Throughput Laboratories
The changing function of the modern lab environment results in additional challenges requiring flexible task-specific solutions to minimize environmental impact, protect operator safety, and optimize overall process efficiency. In particular, the need to identify new drag components in the pharmaceutical industry has resulted in the use of advanced concepts of combinatorial chemistry requiring employment of automated analysis/discovery processes utilizing sophisticated computer and high-throughput robotic technology. It is well documented that handling solid and liquid toxic compounds results in aerosol generation (Sansone & Losikoff, 1977), requiring these operations to be performed in wellventilated hoods. Likewise, many automated laboratory practices produce aerosols and particulates (e.g., weighing, pipetting, transferring, handling, autoclaving, and incubating). While robotic operations do not require continuous operator presence in front of the robotic equipment, routine equipment access and regular maintenance result in a significant risk of worker exposure. The need to contain these automated operations within vented enclosures is further reinforced by the documented cases of air and surface contamination during robotic handling of compounds of unknown toxicity. For instance, a recent study (Cooper, 2003) was conducted to investigate the potential for air and surface contamination with compounds of unknown toxicity during robotic operations. It indicated that there were detectable model compound levels present in air samples taken near the balance when the robot malfunctioned and dropped a vial, spilling its components. Thus, this clearly emphasized the need for robotic systems to be contained within appropriate vented enclosures to minimize the potential for inhalation exposure. Conventional containment solutions (i.e., chemical hoods, biosafety cabinets, and/or glove boxes) are ill-suited for the task of robotic containment due to increased turbulence levels and airflow obstructions produced by the robot geometry, thus requiring enclosure design to permit adequate contaminant removal and provide efficient operator and sample protection. Computational fluid dynamics (CFD) (i.e., computer modeling of air and gas flows) provides unique insight into the detailed flow field characteristics of the entire ventilation process. It allows for studying the airflow patterns within the enclosure/robot system by providing directional velocity distribution within the enclosure and around the robotic equipment, hence pointing out the areas of potential concentration build-up and crosscontamination. Subsequent computer modeling iterations can be used to optimize enclosure geometry and operation to ensure smooth airflow movement within the robot work area. In addition, the exhaust characteristics of the enclosure can be modified to address the capture velocity at access openings Applied Biosafety, 9(4) pp. 188-199 © ABSA 2004 Article
Toxicological data on NOx: an overview.
This overview is based on experimental and epidemiological studies of NOx toxicity during the past decade. Approximately 130 published studies are cited and about one-fourth of these are discussed briefly under one of the following headings: acute and subacute studies, chronic low-level studies, human studies, and special studies. The latter section examines a selection of comparatively unique investigations, including several devoted to the pulmonary uptake and retention of NO2, and several examining the potential tumorigenicity of NO2. For each major section of the overview, a critical evaluation is attempted in terms of the impact of the appropriate studies on the extant NOx toxicological data base and on the current and planned air quality standards for NOx.