Characterization of cooking-related ultrafine particles in a US residence and impacts of various intervention strategies

Abstract

Interventions that improve air exchange or filter the air have the potential to reduce particle exposures from residential cooking. In this study, we evaluated the effect of using a range hood, opening kitchen windows, and using portable air cleaners (PACs) in various home locations on the concentrations of ultrafine particles (UFPs) at different times and in different rooms during and after cooking. All experiments were conducted using a standardized cooking protocol in a real-world naturally-ventilated apartment located in the northwest United States. Real-time UFP measurements collected from the kitchen, living room, and bedroom locations were used to estimate parameters of a dynamic model, which included time-varying particle emission rates from cooking and particle decay. We found that 1-min mean UFP number concentrations in the kitchen and living room mostly peaked within 0-10 min after cooking ended at levels of 150,000-500,000 particles/cm³. In contrast, the bedroom UFP concentrations were consistently low except for the window-open scenario. While varying considerably with time, the 1-min UFP emission rates were comparable during and within 5-min after cooking, with means (standard deviations) of 0.8 (1.1) × 10¹² and 1.1 (1.2) × 10¹² particles/min, respectively. Compared with the no-intervention scenario, keeping the kitchen windows open and using a kitchen range hood reduced the mean indoor average UFP concentrations during and 1 h after cooking by ~70% and ~35%, respectively. Along with the range hood on, utilizing a PAC in the kitchen during and after cooking further reduced the mean indoor average UFP levels during and 1 h after cooking by an additional 53%. In contrast, placing the PAC in the living room or bedroom resulted in worse efficacy, with additional 2-13% reductions. These findings provide useful information on how to reduce cooking-related UFP exposure via readily accessible intervention strategies.

Keywords: Cooking; Emission; Portable air cleaner; Range hood; Ultrafine particle; Window opening.

Fig. 1.

Timeline of the cooking protocol.

Fig. 2.

Time-series plots of 1-min indoor ultrafine particle number concentrations for each scenario. “S1–7” represents Scenarios 1–7. “Average” refers to indoor mean concentration. Note that the living-room UFPs in Scenario 1 were not measured due to the instrument unavailability.

Fig. 3.

Means (standard deviations) of 1-min indoor ultrafine particle concentration increases during and 1-h after cooking compared with before-cooking levels in each scenario. “S1–7” represents Scenarios 1–7. “During”, “After”, and “D&A” refer to during cooking, 1-h after cooking, and pooled period, respectively. “Average” refers to indoor mean concentration. Note that the living-room UFPs in Scenario 1 were not measured due to the instrument unavailability.

Fig. 4.

Time-series plots of 1-min cooking-related ultrafine particle emission rates for each scenario. “S1–7” represents Scenarios 1–7. Dishes 1 and 2 refer to the steak and asparagus, respectively.