Indoor Particulate Matter during HOMEChem: Concentrations, Size Distributions, and Exposures

It is important to improve our understanding of exposure to particulate matter (PM) in residences because of associated health risks. The HOMEChem campaign was conducted to investigate indoor chemistry in a manufactured test house during prescribed everyday activities, such as cooking, cleaning, and opening doors and windows. This paper focuses on measured size distributions of PM (0.001-20 mu m), along with estimated exposures and respiratory-tract deposition. Number concentrations were highest for sub-10 nm particles during cooking using a propane-fueled stovetop. During some cooking activities, calculated PM2.5 mass concentrations (assuming a density of 1 g cm(-3)) exceeded 250 mu g m(-3), and exposure during the postcooking decay phase exceeded that of the cooking period itself. The modeled PM respiratory deposition for an adult residing in the test house kitchen for 12 h varied from 7 mu g on a day with no indoor activities to 68 mu g during a simulated day (including breakfast, lunch, and dinner preparation interspersed by cleaning activities) and rose to 149 mu g during a simulated Thanksgiving day.