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FIELD EVALUATION OF NANOFILM DETECTORS FOR MEASURING ACIDIC PARTICLES IN INDOOR AND OUTDOOR AIR
Impact/Purpose:
Over the last several decades, evidence has accumulated suggesting that exposure to airborne particulate matter (PM), which includes particles of varying composition and sizes (coarse, fine, and ultrafine), may affect the human cardiovascular and respiratory systems. Although ultrafine particles constitute a small percentage of the total PM mass in the size category regulated by the EPA through the National Ambient Air Quality Standards (PM < 2.5 µm in aerodynamic diameter), they are present in high number concentrations.
Much research has been conducted to learn how each component of PM contributes to its health effects in order to help inform decisions on ambient PM standards and pollution control strategies. Such research, especially in population studies, has been hampered by the lack of portable instruments that can measure the personal exposure levels of specific PM components. Dr. Beverly Cohen and colleagues at New York University Medical Center propose to test a new iron-coated nanofilm for collecting and measuring ambient concentrations of acidic ultrafine PM. Cohen and colleagues hypothesize that because small particles are more likely than larger particles to deposit in the lower respiratory tract, and particle acidity is known to damage lung tissues, acidic ultrafine particles may be especially toxic.
Description:
Dr. Beverly Cohen and her colleagues at New York University School of Medicine will test the performance of iron nanofilms to collect and measure sulfuric acid particles of different sizes under a variety of temperature and humidity conditions. The iron nanofilm detector is a thin iron-coated silicon chip. Particles would react with the iron, creating an elevated site or bump on the film surface, which can be visualized using an atomic force microscope. The investigators will test the performance of iron nanofilms preexposed to laboratory-generated sulfuric acid particles of different sizes under a variety of storage conditions. They will also conduct a field study, using two types of air samplers for ambient monitoring, an electrostatic aerosol sampler and an ultrafine diffusion monitor.