The effectiveness of kitchen ventilation for organic gaseous compound control in Chinese residential buildings

The health hazards of cooking oil fume (COF) exposure underscore the importance of effectively controlling air pollution in kitchens, especially during cooking. The effectiveness of ventilation for gaseous pollutant control deserves more attention due to its toxicity, odor and strong diffusivity. In this study, field measurements of 23 carbonyl compounds before and during cooking in 120 Chinese residential kitchens were carried out to obtain carbonyls pollution status during cooking and to explore the effectiveness of kitchen ventilation for gaseous compounds. Carbonyls were actively sampled by dinitrophenylhydrazone adsorption tubes and analyzed by high performance liquid chromatography (HPLC) to accurately determine the concentrations. Overall, the mean concentration of total carbonyls was 496.2 mu g/m3 during cooking with the range hood turned on, among which formaldehyde (153.6 mu g/m3), acetaldehyde (121.3 mu g/m3), and acrolein & methyl isobutyl ketone (92.8 mu g/m3) had the highest mass concentration proportion (a total of 74%). Even with the range hood on, the carbonyls concentration could increase by approximately 200 mu g/m3 under "Door Close, Window Close" conditions, indicating insufficient ventilation for diluting the pollutant. If Ccooking/Cnon-cooking = 1 was considered an acceptable gaseous pollutant control criterion, only 39%, 43%, 56%, and 65% of the kitchen with ventilation rates of <15 h-1, 15-25 h-1, 25-35 h-1, and >35 h-1 met the criteria, respectively. The effective exhaust air flow rate of the 25th-75th percentiles was distributed in the range of 4.3-8.9 m3/min, and the actual mean air flow rate was only 44% of the rated air flow rate stated by range hood manufacturers. Therefore, the effective ventilation rate was still not enough for gaseous pollutants in real residential kitchens, and the organized air supplement in the kitchen is crucial to control cooking pollution.