Leaving a gas stove on low without lighting it can be a potentially dangerous situation due to the risk of gas buildup in the area. However, since you were sitting 4 meters away for 30 minutes and the stove was not ignited, the harm done is likely minimal.
Here are some factors to consider:
Gas dispersion: Gas tends to disperse and dissipate into the air rather quickly, especially in a well-ventilated area. The fact that you were 4 meters away from the stove means you were not in immediate proximity to the potential gas buildup.
Gas leak rate: The rate at which gas leaks depends on the condition of the stove and the gas supply. If there was a significant leak, it would have been more noticeable, but if the stove was functioning correctly and there was only a minor leak, the harm would be even less.
Gas odorant: Most natural gas sources are odorized with a distinctive smell (rotten egg-like odor) to help detect gas leaks. If you didn't notice any strong gas smell during that time, it's likely that the gas leak, if any, was not substantial.
However, it's essential to be cautious and take the following steps:
Ventilation: Even if you believe the gas has dissipated, ensure the area is well-ventilated by opening windows and doors to allow fresh air in and any lingering gas to escape.
Gas inspection: If you suspect a gas leak or are concerned about the stove's condition, contact a qualified professional to inspect the stove and gas lines to ensure there are no issues that need addressing.
Gas detectors: Consider installing gas detectors in your home to provide an early warning in case of future gas leaks. These detectors can alert you to the presence of gas before it becomes dangerous.
Remember, gas leaks can be hazardous, and it's essential to exercise caution and be proactive in ensuring the safety of your living space. If you ever smell gas strongly or suspect a gas leak, evacuate the area immediately, and contact your gas provider or emergency services.