Household air pollution has adverse effects on cardiovascular health. One of the major sources of household air pollutants is the combustion of cooking oils during cooking. Trans, trans-2,4-decadienal (tt-DDE) is a type of dienaldehyde that is present in a wide range of food and food products. It is a byproduct of the peroxidation of linoleic acid following the heating of oil during cooking. The mechanisms of the associations between household air pollution and cardiac arrhythmias are currently unclear. The purpose of this study was to determine effects of tt-DDE on the ion currents in H9c2 cells. The I K and I Ca,L in H9c2 cells treated with and without tt-DDE were measured using the whole-cell patch clamp method. Expressions of Kv2.1 and Cav1.2 in H9c2 cells treated with and without tt-DDE were measured by western blot analysis. After the H9c2 cells had been exposed to tt-DDE, the I K and i Ca,L were significantly decreased. The expression of Kv2.1, unlike that of Cav1.2, was also significantly decreased in these cells. These changes in I K and I Ca,L that were induced by tt-DDE may help to explain the association between cardiac arrhythmogenesis and cooking-oil fumes.Epidemiological studies have revealed that exposure to air pollutants, especially particulate matter (PM), is associated with an increased incidence of respiratory diseases, as well as of cardiovascular morbidity and mortality 1,2 . Exposure to air pollution could increase the risks of ischemic heart disease, heart failure, cerebrovascular disease, and cardiac arrhythmias 3,4 . In the Air Pollution and Cardiac Risk and its Time Course (APACR) study, 60 minutes of exposure to PM 2.5 (particles with a diameter of ≤2.5 μm) was associated with increased premature ventricular contractures 5 . Another study demonstrated that brief exposure to air pollution could trigger atrial fibrillation 6 . The mechanisms of the associations between air pollution and cardiovascular diseases are currently unclear. It has been proposed that increased systemic inflammatory responses, systemic oxidative stress, systemic and pulmonary artery blood pressure, and risks of atherosclerosis, as well as changes in autonomic function indicate increased cardiovascular morbidity and mortality caused by air pollution 7-9 .As comprehensively demonstrated in previous studies, household air pollution also has adverse effects on cardiovascular health 10 . Indoor exposures to PM 2.5 is associated with alternation of heart rate variability that could in turn increase vulnerability to cardiac arrhythmias 11 . One of the major sources of household air pollutants is the combustion of cooking oils during cooking. A longitudinal study conducted by Chinese military cooks showed that exposure to compounds derived from cooking-oil fumes could cause oxidative DNA damage and lipid peroxidation 12 . However, the effects of the contents of cooking-oil fumes on vulnerability to cardiac arrhythmias is unknown. Trans, trans-2,4-decadienal (tt-DDE) is a type of dienaldehyde that is present in a wide ran...