To investigate the potential soiling hazard to works of art posed by the deposition of airborne particles, time resolved measurements were made of the size distribution and chemical composition of particles inside and outside of three southern California museums. The measured indoor aerosol characteristics agree well with predictions of a mathematical model of indoor aerosol dynamics based on measured outdor aerosol characteristics and building parameters. At all three sites, the fraction of particles entering from outdoor air that deposit onto surfaces varies strongly with particle size, ranging from a minimum of 0.1-0.5% for particles having a diameter in the vicinity of 0.15 um to greater than 90% for particles larger than 20 um in diameter. Deposition calculations indicate that, at the rates determined for the study days, enough elemental carbon (soot) would accumulate on vertical surfaces in the museums to yield perceptible soiling in as little as one year at one site to as long as 10-40 years at the other two sites.
Lynn Garry Salmon <>{