Cooking emissions have long been seen as an odor problem. Howeverrecent studies showed that Particulate Matter (PM) is the main health risk ofindoor air and cooking can be a major source. A small field study within 9Dutch dwellings indicates that depending on the conditions cooking can have arelatively large effect on the indoor exposure to PM2.5. Four determiningvariables have been identified. First the cooking method: lids on or off, cookingon gas or induction and the type of food has a large effect. In general meatfrying seems to generate significant PM. Second the type of range hood and theexhaust flowrate. Based on this limited study the best are motorized hoods witha high exhaust flow, followed by recirculation hoods, motorless hoods with ahigh exhaust flow and lastly motorless hoods just complying with the building standard.The third parameter is the amount of ventilation compared to the volume of thekitchen / livingroom in relation to the exhaust flowrate. In some of the largerrooms the exposure was quite high even though the peak concentration was not,due to the fact that it took several hours to reduce the concentration toacceptable levels. The fourth parameter is the infiltration of ambient PM2.5,by the ventilation system.