oil fire on the stove. Japan, South Korea and China have regulated the addition of electronic safety devices to prevent pan overheating. The devices use a thermistor to monitor the temperature close to the pan, and cut off the gas supply if the heat is too high. Fire loss statistics for Japanese gas stoves showed a reduction in house fires caused by gas stoves in the years following 2008, when the safety devices were mandated. Efficiency The U.S. Department of Energy (DOE) ran tests in 2014 of cooktop energy transfer efficiency, simulating cooking while testing what percentage of a cooktop's energy is transferred to a test block. Gas had an efficiency of 43.9%, with ±0.5% repeatability in the measurement. This level of efficiency is only possible if the pan is big enough for the burner. Japanese gas flames are angled upwards towards the pot to increase efficiency. The efficiency of gas appliances can be raised by using special pots with heatsink-like fins. Jetboil manufactures pots for portable stoves that use a corrugated ribbon to increase efficiency. Health concerns Carbon monoxide, formaldehyde, and nitrogen dioxide from gas stoves contribute to indoor air pollution. Nitrogen dioxide can exacerbate respiratory illnesses, such as asthma or chronic obstructive pulmonary disease. Studies have been performed correlating childhood asthma and gas stoves. A 1999–2004 study published in The Lancet Respiratory Medicine found "no evidence of an association between the use of gas as a cooking fuel and either asthma symptoms or asthma diagnosis". A 2013 meta-analysis concluded that gas cooking increases the risk of asthma in children. A 2020 Lancet systematic review surveyed 31 studies on gas cooking or heating, finding a pooled risk ratio of 1.17 for asthma. One study found that in households with gas stoves those that report using ventilation had lower rates of asthma than those that did not. A 2023 meta-analysis estimated that in the United States, one in eight cases of asthma in children are due to pollution from gas stoves. The asthma risk caused by gas stove exposure is similar in magnitude to that caused by secondhand smoke from tobacco. Stoves can cause levels of nitrogen dioxide that can exceed outdoor safety standards. A 2020 RMI report found pollution from gas stoves causes exacerbation of asthma symptoms in children. Cooking, especially high heat frying, releases smoke (measured as fine particulate matter), acrolein and polycyclic aromatic hydrocarbons. Mitigating indoor particulate