Several recent studies have indicated signi cant health risks associated with exposure to ne particles as measured outdoors. However, much of the exposure is believed to have occurred indoors. Consequently, there is considerable interest in the relationship between indoor and outdoor ne particles. This paper describes some results from a study in which the processes of particle removal from in ltrating air by building envelopes are simulated in a chamber. The chamber consists of two compartments, each having a volume of 19 m 3 . Particles with aerodynamic diameters in the range of 0.05 to 5 ¹m are generated in one compartment and then transported through simulated leakage paths to the other compartment under the action of applied pressure differentials. The simulated leakage paths described in this paper consist of horizontal slits (0.508 mm high, 102 mm deep, and 433 mm wide) between aluminum plates. The penetration factor for each size particle is determined by simultaneously measuring the concentrations in the two compartments as a function of time. The penetration factor is obtained through a mathematical solution of the mass balance equations. The measured values of penetration are compared to predictions of a mathematical model describing deposition by the mechanisms of settling and diffusion. At applied pressures of 2 Pa, only 2% of 2 ¹m particles and 0.1% of 5 ¹m particles pass through the 0.508 mm high slits. At a pressure of 5 Pa, 40% of 2 ¹m particles and <1% of 5 ¹m particles pass through the slits. At 10 Pa, 85% of 2 ¹m particles and <1% of 5 ¹m particles pass through the slits. At 20 Pa, 90% of 2 ¹m particles and 9% of 5 ¹m particles pass through the slits. Measured deposition rate constants for particles spanning the range 0.015 to 5 ¹m in diameter are shown.

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The surface oil burns conducted by the U.S. Coast Guard from April to July 2010 during the Deepwater Horizon disaster in the Gulf of Mexico were simulated by small scale burns to characterize the pollutants, determine emission factors, and gather particulate matter for subsequent toxicity testing. A representative crude oil was burned in ocean-salinity seawater, and emissions were collected from the plume by means of a crane-suspended sampling platform. Emissions included particulate matter, aromatic hydrocarbons, polychlorinated dibenzodioxins/dibenzofurans, elements, and others, the sum of which accounted for over 92% by mass of the combustion products. The unburned oil mass was 29% of the original crude oil mass, significantly higher than typically reported. Analysis of alkanes, elements, and PAHs in the floating residual oil and water accounted for over 51% of the gathered mass. These emission factors, along with toxicity data, will be important toward examining impacts of future spill burning operations.