Improvement in contamination control for a LCD color filter coater was studied by using a mini-environmental design. Different operating conditions of the door and the exhaust of the mini-environment were studied. Measurements of particle concentration flow field, and VOC concentration were performed. Both the particle contamination to the coating process and the VOC contamination to the outside cleanroom environment were considered in this study. lt was found that a minienvironment could be designed to significantly reduce the particle concentration.
Five classrooms, air-conditioned or naturally ventilated, at five different schools were chosen for comparison of indoorand outdoor air quality. Temperature, relative humidity (RH), carbon dioxide (C02), sulphur dioxide (S02), nitric oxide (NO), nitrogen dioxide (N02), particulate matter with diameter less than 10 μm (PM10), formaldehyde (HCHO), and total bacteria counts were monitored at indoor and outdoor locations simultaneously. Respirable particulate matter was found to be the worst among parameters measured in this study.
Forced air furnaces are a common Canadian heating system. Traditionally, filters placed in thecirculating air ductwork were designed to protect the furnace and fans. Over the last severalyears, there has been increased emphasis on improving the filtration efficiency with the goal ofreducing occupant exposure to respirable particulate. The current research project rotatedseveral filters through six houses in southern Ontario during the heating season.
Recent research suggests that fine-particulate air pollution increases the incidence of lung disease and pre-mature death. Single fibre filter theory is used to predict the theoretical particulate collection efficiency of air permeable walls (dynamic insulation). The relationship between particle diameter and filtration efficiency for dynamic insulation, as a function of flow rate, is examined and compared to that for a conventional filter.
A semi-empirical two-compartment constant parameter model is used to predict airborne and surface du t concentrations. The model parameters are air in- and exfiltration internal particle sources, surface deposition caused by settling. Brownian and turbulent diffusion and thermophoresis track-in of dust particle and resuspension. Model predictions are calculated for some typical scenarios, and the soiling rate of a vertical surface is calculated for a range of friction velocities and electric field strengths.
Airborne particulate matter is an important form of pollution, which has generated increasing concern in recent years. As well as contributing to poor visibility and surface soiling, airborne particulate matter can have adverse effects on human health. Construction and other civil engineering sites have been perennial sources of nuisance dust (that is, dust deposited on surfaces and generating complaint). However, there is currently no formal advice or Code of Practice for regulating the emission of particles from construction activity.
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