HYGROSCOPICITY OF INDOOR AEROSOLS AND ITS INFLUENCE ON THE DEPOSITIONOF INHALED RADON DECAY PRODUCTS

Consumer spray products, combustion products, and cooking aerosols are the significant sources of airborne particles to the indoor atmospher e. These particles serve as carriers of radon decay products to the lu ngs. When inhaled, some particles will extract water from the air at t he high relative humidity (RH similar to 99.5%) in the respiratory tra ct and grow in size. Since the deposition of particles in different co mpartments of the lungs, and hence the inhaled dose, depends on the si ze of the particles, it will be different for the particles that grow from those that do not. The study of the hygroscopic growth of these i ndoor aerosol particles was performed using a tandem differential mobi lity analyzer. Dry monodisperse particles of known initial size were s elected by the first differential mobility analyzer (DMA) and then exp osed to high RH (99-99.5%) in a growth chamber using a wetted water re actor. The size of these particles was measured by the second DMA. It was observed that some products do not grow at all, whereas others exh ibit moderate to high growth. A comparative study of the deposition of the inhaled growing and non-growing particles, and its influence on t he Lung dosimetry, is presented. Copyright (C) 1996 Elsevier Science L td.