What impact does altitude have on engine performance?

Altitude has a significant impact on engine performance primarily due to changes in air density. As altitude increases, the density of the air decreases, which means that there is less oxygen available for combustion in the engine. This reduced oxygen availability directly affects the amount of fuel that can be effectively burned, leading to less overall power output from the engine.

Engines are designed to operate optimally at a specific air density, usually found at lower altitudes. At higher altitudes, the air becomes thinner, resulting in a leaner fuel-air mixture. This means that even though the engine may still run, it is unable to produce the same amount of power as it would at sea level. Consequently, it typically decreases engine power due to lower air density, making it more challenging for vehicles to perform optimally in high-altitude conditions.

In contrast, the other options suggest misconceptions about altitude's effects on engine performance. Some might think that altitude could increase engine power, but this is misleading because the lower density leads to less oxygen and, subsequently, less power. Similarly, stating that altitude has no effect on engine power ignores the fundamental principles of combustion and air density. The idea that higher altitude would result in higher emissions is also inaccurate, as the reduced power output often