How many meters can gasoline evaporate before it loses its odor?

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Hello, I asked about the safe concentration a couple of days ago but didn’t receive a reply. That’s what I think ； I’d like to discuss this with my colleagues ； In areas close to the interfaces for filling with oil or benzene at the tank farm, there is a very strong odor. Additionally, the evaporation from the vents on the oil tanks results in a high concentration of oil and gas in the area around them, giving off a strong smell; as the distance increases, the smell becomes weaker. At a certain distance, the oil and gas essentially have no odor. At this point, it might be the case that although the human sense of smell cannot detect any smell, the oil and gas are still evaporating to some extent. Being exposed to such concentrations for an extended period can be harmful to the body, even though no odor is perceptible. Therefore, a detector is needed to ensure safety. Beyond this distance, the concentration of oil and gas becomes very low; it’s not because the human sense of smell isn’t that sharp, but rather because the oil and gas have not spread that far. So it can’t be smelled. The question I want to ask is ； At a distance of around 100 meters, is it such a distance where the sense of smell is less sensitive and nothing can be detected, or is it still a distance at which there is a certain concentration of the vapor, or has it become too far away for the vapor to reach that area? Of course, there is another situation in which hydrocarbons are not detectable despite having a high concentration: the hydrocarbons themselves have no odor, so no matter how high the concentration, they cannot be smelled. In our facility, when blending gasoline, we connect the pipes directly to the oil tank and then use those pipes to transfer the mixture out. The storage capacity of the oil depot is 1,000 tons, and not all of the raw materials are used for blending each time. During the harmonization process, the sealing operation prevents the raw materials from coming into contact with air, aside from any volatilization through pores. Based on this, may I ask what situation it is when I can’t smell anything? Thank you so much!