Particulate emissions from cooking activities: emission factors, emission dynamics, and mass spectrometric analysis for different preparation methods

Abstract. As most people, especially in developed countries, spend most of their time indoors, they are strongly exposed to indoor aerosol, which potentially can lead to adverse health effects. A major source of indoor aerosols are cooking activities releasing large amounts of particulate emissions, both number and mass wise, with often complex composition. To investigate the characteristics of cooking emissions and parameters, which influence these characteristics, we conducted a comprehensive study in form of a measurement series cooking 19 dishes with different ingredients and preparation methods. The emissions were monitored in real time with multiple online instruments measuring physical and chemical particle properties as well as trace gas concentrations. With the same instrumentation, the influence of cooking emissions on the ambient aerosol load was studied at two German Christmas markets.

For six variables, we observed changes during the cooking: particle number concentration of smaller (particle diameter d_p > 5 nm) and larger particles (d_p > 250 nm), PM (PM₁, PM_2.5, PM₁₀), BC, PAH and organics mass concentrations. Generally, similar emission characteristics were observed for dishes with the same preparation method mainly due to similar cooking temperature and use of oil. The emission dynamics of the above-mentioned variables as well as the sizes of emitted particles were mostly influenced by the cooking temperature and activities during cooking. The emissions were quantified via emission factors, with the highest values for grilled dishes, one to two orders of magnitude smaller ones for oil-based cooking (baking, stir-frying, deep-frying) and the smallest for boiled dishes.

For the identification of cooking emissions with the Aerodyne aerosol mass spectrometer (AMS) and generally the identification of new AMS markers, we propose a new diagram type where the variability of the mass spectra of different aerosols is considered. Combining our results and those from previous studies for quantification of cooking-related organic aerosol with the AMS, we recommend using values for the relative ionization efficiency which are larger than the default value for organics (RIE_Org = 1.4): for rapeseed oil-based cooking 2.17 ± 0.48 and for soy oil-based cooking 5.16 ± 0.77.