Source Strengths of Ultrafine and Fine Particles Due to Cooking With a Gas Stove
L A. Wallace, Steven Emmerich, Cynthia H. Reed
Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes produced during cooking. In this study, particles in 124 size bins from 0.01 mm to 2.5 mm were measured continuously over two years in an occupied home. Tracer gas measurements were made every 10 minutes in 10 rooms of the house to establish air change rates. Specific cooking episodes (N = 39) were selected and the number and volume of particles produced was determined for each size category. For each episode, the particle decay rate was determined and used to determine the source strength for each size category. Deep frying in oil was capable of producing about 1014 particles, more than 90% of them in the ultrafine (<0.1 mm) range, with an estimated whole-house volume concentration of 50 (mm/cm)3, more than 60% of this volume occurring in the 0.1-0.3 mm range. Frying produced peak numbers of particles at about 0.06 mm, with a secondary peak at 0.01 mm. The peak volume occurred at about 0.16 mm. Particle production from frying in oil appeared to be nonlinear, with the largest contribution occurring just as the oil reached its highest temperature. This phenomenon limits the utility of the source strength estimates since slightly different types of cooking might yield very different particle concentrations. Cooking episodes during the morning and evening were compared to non-cooking episodes at the same times over a period of one year. Breakfast cooking (mainly heating water for coffee and using an electric toaster) produced concentrations less than half those produced from more complex dinnertime cooking. However, even breakfast cooking produced ultrafine particle number concentrations up to an order of magnitude higher than those times when no cooking occurred.
Environmental Science & Technology
air change rates, continuous air monitors, deposition reates, indoor air quality