Cooking Oil Mixed with Residential Wood Burning Particles: A Wintertime Indoor Air Quality Study

Indoor air quality is important as humans spend significant time indoors, especially in colder climates. Household activities, including cooking and home heating, and infiltration of outdoor air contribute to gases and aerosols indoors. To study interactions of indoor aerosol sources, a single-particle mass spectrometer measured the size and chemical composition of individual aerosol particles inside a residential home in the winter in Fairbanks, Alaska. We focus on indoor measurements during nine cooking experiments, including five experiments with indoor home heating pellet stove burning. The three main single-particle types identified from the 70,384 individual particles (0.07–2 μm) measured during cooking were cooking oil-dominant, smoke (from indoor and infiltrated outdoor home heating), and smoke + cooking oil. Smoke + oil was the most abundant particle type (9–76%, by number, across the cooking experiments). Fatty acids and tocopherols from cooking oil were present in 71%, by number, of all measured particles during cooking. Indoor number mode diameters increased following cooking, supporting particle growth via coagulation of cooking oil particles with pre-existing wood smoke particles indoors and condensation of semivolatile cooking oil onto these particles. The physical mixing of smoke and cooking oil indoors demonstrates the interactions of aerosol sources in the indoor environment.