There is a high lung cancer prevalence in females in Taiwan with a relatively low number of smokers. Exposure to air pollution from cooking (APC) has been suspected as one of the major risk factors for lung cancer since cooking is one of the major sources of particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) in household buildings. Many studies have demonstrated that occupational exposure (40h per week) to APC in commercial kitchens and restaurants could cause a cancer risk higher than 10-6. However, currently the data of exposure to APC in household kitchens are relatively few in Taiwan. Therefore, we conducted a health risk assessment for exposure to APC in five household kitchens in northern Taiwan during 2010-2011.Twenty-four-hour monitoring of the particle concentration shows that particle number concentrations during non-cooking hours ranged from 1220 to 6200particles/cm3 and increased to 1,400,000particles/cm3 during cooking hours, and most of these particles are ultrafine ones. Some of the measurement results (PM10>80μg/m3 at 3 kitchens) exceed the current indoor air quality standards of Taiwan. The gas-particle partitioning of PAHs in household APC indicates that most of the low molecular PAHs (2 and 3 rings) are in the gas phase, while the high molecular PAHs (more than 4 rings) are particle-bound. The particulate-phase PAHs contribute more than 95% of the benzo[a]pyrene equivalent concentration. The incremental lifetime cancer risk resulting from exposure to the household APC could be higher than the acceptable level of 10-6, and thus of health concerns.