What is meant by “fuel volatility”?

Fuel volatility refers to the tendency of a fuel to evaporate, which is significant because it impacts both combustion efficiency and emissions. When fuel has high volatility, it can vaporize more readily, which is crucial for effective combustion in engines. This vaporization helps to create the necessary air-fuel mixture that ensures smooth engine operation and optimal power output. Volatility also plays a role in emissions; fuels that evaporate easily can lead to higher emissions of volatile organic compounds (VOCs) during combustion, contributing to air pollution and affecting environmental regulations.

In contrast, the other options focus on different properties of fuel that, while relevant in their own contexts, do not specifically define volatility. Fuel stability at varying temperatures is important for safe handling and storage but does not directly describe volatility. Transport speed addresses logistical considerations of moving fuel rather than its chemical characteristics. The presence of contaminants is a matter of fuel quality, but it does not relate to how readily the fuel evaporates under certain conditions.