The Composition of Emissions from Sanding Corian® with Different Sandpapers.

Laboratory tests were conducted to characterize the composition of emissions from sanding Corian®, a solid-surface composite material mainly composed of alumina trihydrate (ATH) and acrylic polymer. Three sandpaper materials (ceramic, silicon carbide, and aluminum oxide) were tested to distinguish the contribution of aluminum-containing dust in the emission from Corian® and sandpaper itself. The result can help identify the main cause of the pulmonary fibrosis from exposure to aluminum-containing dust while sanding Corian®. Airborne dust samples were measured using direct-reading instruments and collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI) for estimating the normalized dust generation rate. The size-classified dust samples from MOUDI were analyzed for elemental aluminum content. Additionally, air samples were analyzed for characterizing methyl methacrylate (MMA). The results from the direct-reading instruments reveal that the size distribution of particulate from sanding Corian® differs from that of sawing Corian®, showing that the size distribution of dust is affected by the fabrication process. The normalized respirable dust generation rate indicates that more respirable dust was generated during sanding Corian® board. However, the use of aluminum oxide sandpaper does not result in a higher aluminum content in the respirable dust from sanding Corian®, suggesting that the aluminum content of the respirable dust is primarily originated from Corian® itself. The generation rates of MMA from sanding did not vary much among all types of sandpapers, and they were much lower than that of sawing, likely due to the higher temperature in the sawing process.

The Composition of Emissions from Sawing Corian®, a Solid Surface Composite Material.

We conducted detailed analyses of the composition of emissions from sawing Corian®, a solid surface composite material, in a laboratory testing system. The analyses included the aluminum content of size-selective dust samples, semivolatile organic compounds (SVOCs) in respirable dust samples, and volatile organic compounds (VOCs). The normalized respirable dust generation rate found using a Micro-Orifice Uniform Deposit Impactor was 5.9 milligrams per gram (mg g-1) suggesting that 0.59% of the mass removed from sawing Corian® becomes respirable dust. The alumina trihydrate content of the dust was consistently above 85% in most parts of the respirable size range, verifying an earlier finding that it is the dominant composition of the airborne particles of all sizes, including ultrafine particles. VOC analyses revealed that methyl methacrylate (MMA) was the most abundant compound, with a generation rate of 6.9 mg g-1 (0.69% of the mass removed from sawing Corian® became MMA vapor). The SVOC analysis only found a small amount of MMA (0.55%) in the bulk dust.

Characterization of an Aerosol Microconcentrator for Analysis Using Microscale Optical Spectroscopies.

Efficient microconcentration of aerosols to a substrate is essential for effectively coupling the collected particles to microscale optical spectroscopies such as laser-induced or spark microplasma, or micro-Raman or infrared spectroscopies. In this study, we present detailed characterization of a corona-based aerosol microconcentration technique developed previously (Diwakar and Kulkarni, 2012). The method involves two coaxial electrodes separated by a few millimeters, one held at a high electrical potential and the other grounded. The particles are collected on the collection (i.e., ground) electrode from a coaxial aerosol flow in a one-step charge-and-collect scheme using corona discharge and electrical precipitation between the two electrodes. Performance of the corona microconcentration method was determined experimentally by measuring collection efficiency, wall losses, and particle deposition density. An intrinsic spectroscopic sensitivity was experimentally determined for the aerosol microconcentrator. Using this sensitivity, we show that corona-based microconcentration is much superior to alternative methods, including filtration, focused impaction using aerodynamic lens, and spot collection using condensational growth. The method offers unique advantages for compact, hand-held aerosol analytical instrumentation.