Which of the following increases density altitude?

Density altitude is a measure that combines the effects of temperature, pressure, and humidity to indicate air density at a specific elevation. When discussing factors that increase density altitude, it refers to conditions that contribute to lower air density, which is critical for aircraft performance.

Increased temperature contributes to a higher density altitude because warmer air is less dense than cooler air. When temperature rises, the air expands, leading to a decrease in air density. Similarly, an increase in elevation carries with it a decrease in air pressure, which also leads to a reduction in air density. This combination of higher temperature and increased elevation effectively raises the density altitude, as the air becomes less dense than it would be at lower elevations or at cooler temperatures.

This option captures both critical concepts—temperature and elevation—highlighting that higher values of both result in increased density altitude, making it the correct answer. Conditions such as decreased pressure and increased humidity do influence air density and performance, but they do not directly determine density altitude increases in the same comprehensive manner as temperature and elevation combined do.